Background
Vitamin C (ascorbic acid) is an essential water-soluble vitamin that the body cannot make on its own. It plays a key role in collagen production, antioxidant defense, and iron absorption. For hair health, vitamin C supports strong hair structure and protects follicles from oxidative stress.

Origin, Source, and Traditional/Historical Use
Vitamin C is found naturally in citrus fruits, berries, peppers, and leafy greens. Historically, vitamin C deficiency caused scurvy, a disease marked by weak connective tissue and hair loss, which was prevented when sailors consumed citrus.

Key Active Compounds and Chemical Composition
Vitamin C (C6H8O6) exists in two forms: ascorbic acid and dehydroascorbic acid. Both act as antioxidants and enzyme cofactors, especially in hydroxylation reactions needed for collagen synthesis.

Bioavailability, Absorption, and Metabolism
Vitamin C is absorbed in the small intestine via sodium-dependent transporters (SVCT1, SVCT2). Bioavailability decreases at higher doses, with ~70–90% absorbed at intakes below 200 mg. It is widely distributed to tissues, metabolized in the liver, and excess is excreted in urine.

Current Availability and Use
Vitamin C has been available as a supplement since the 1930s and is one of the most commonly consumed vitamins worldwide. It is widely used for immune health, skin, and hair, with long-term daily use shown to be safe.

Clinical Features

• Collagen synthesis: Vitamin C is required for producing collagen, the protein that strengthens hair shafts and follicles.
• Antioxidant defense: Reduces oxidative stress in scalp tissues, protecting hair follicles from free radical damage.
• Iron absorption: Improves non-heme iron uptake, preventing hair loss linked to iron deficiency.
• Wound healing: Supports scalp healing and tissue repair.
• Deficiency prevention: Low vitamin C levels are linked with brittle hair and increased shedding.
  
  

Dosing
Recommended daily allowance (RDA): 75 mg for women, 90 mg for men. For hair and skin support, supplements often provide 100–500 mg daily. Best absorbed when spread over 2–3 smaller doses. Available in tablets, capsules, powders, and gummies.

Safety
Vitamin C is very safe at normal doses. High doses above 2000 mg/day may cause diarrhea, nausea, or kidney stones. Safe in children at age-appropriate doses. Safe in pregnancy and breastfeeding within recommended levels.

Mechanism of Action

• Collagen formation: Cofactor for prolyl and lysyl hydroxylases that stabilize collagen structure.
• Antioxidant effect: Neutralizes reactive oxygen species (ROS) in scalp and follicles.
• Iron absorption: Converts ferric iron (Fe3+) to ferrous iron (Fe2+) for better uptake.
• Immune support: Enhances white blood cell activity, reducing inflammation that can harm follicles.
• Keratinocyte function: Supports healthy skin and scalp cell turnover.

Background
Vitamin D3 (cholecalciferol) is a fat-soluble vitamin that acts like a hormone in the body. It supports bone strength, immune defense, and hair follicle health. Low vitamin D levels are linked to hair thinning, shedding, and conditions such as alopecia.

Origin, Source, and Traditional/Historical Use
Vitamin D3 is naturally made in the skin after sunlight exposure (UVB rays). It is also found in fatty fish, egg yolks, and fortified foods. Historically, cod liver oil was used to prevent rickets, a bone disease caused by vitamin D deficiency.

Key Active Compounds and Chemical Composition
Vitamin D3 (C27H44O) is converted in the liver to 25-hydroxyvitamin D (calcidiol) and then in the kidneys to its active form, 1,25-dihydroxyvitamin D (calcitriol). Calcitriol binds to vitamin D receptors (VDRs) found in hair follicles and skin.

Bioavailability, Absorption, and Metabolism
Vitamin D3 is absorbed in the small intestine along with dietary fat. Absorption is improved when taken with a meal. It is stored in fat tissue and released as needed. Blood levels peak within 12–24 hours of supplementation, and full steady-state is reached in 2–3 months.

Current Availability and Use
Vitamin D3 supplements have been widely available since the 1930s and are one of the most used vitamins worldwide. Safe long-term use has been shown when taken within recommended levels.

Clinical Features

• Hair growth: Low vitamin D is strongly linked to hair loss disorders such as alopecia areata and telogen effluvium. Supplementation improves follicle activity within 3–6 months.
• Scalp health: Supports keratinocyte growth and reduces inflammation around follicles.
• Immune regulation: Calms autoimmunity, which may trigger certain hair loss conditions.
• Bone and skin health: Provides structural support that indirectly benefits hair.
• Deficiency correction: Correcting vitamin D deficiency reduces shedding and promotes regrowth.

Dosing
RDA: 600–800 IU (15–20 mcg) daily for adults. Many supplements provide 1000–2000 IU daily for optimal levels. Best taken with food containing fat. Available in capsules, tablets, gummies, and liquid drops.

Safety
Safe at recommended doses. Excess (>4000 IU/day) may cause toxicity, leading to high calcium levels, nausea, and kidney strain. Safe in pregnancy within RDA. Children can take adjusted doses based on age.

Mechanism of Action

• Vitamin D receptor activation: Stimulates hair follicle cycling and stem cell activity.
• Immune modulation: Lowers inflammatory cytokines that damage follicles.
• Keratinocyte regulation: Supports healthy skin and scalp cell turnover.
• Calcium balance: Maintains mineral metabolism important for follicle function.
• Anti-inflammatory: Reduces oxidative stress in scalp tissues.
  
  

Background
Niacin (vitamin B3) is an essential water-soluble vitamin that supports energy metabolism, skin health, and circulation. The form used in supplements, niacinamide, does not cause flushing and is gentle on the stomach. For hair health, niacinamide improves scalp blood flow, reduces inflammation, and strengthens follicle function.

Origin, Source, and Traditional/Historical Use
Niacin was first discovered in the early 20th century while studying pellagra, a disease caused by vitamin B3 deficiency marked by dermatitis, diarrhea, and dementia. Foods rich in niacin include meat, fish, poultry, nuts, and whole grains.

Key Active Compounds and Chemical Composition
Niacinamide (C6H6N2O) is the amide form of vitamin B3. In the body, it is converted into coenzymes NAD+ and NADP+, which are vital for energy production, DNA repair, and cellular signaling.

Bioavailability, Absorption, and Metabolism
Niacinamide is rapidly absorbed in the small intestine, with nearly 100% bioavailability. It is distributed to tissues and converted into NAD+/NADP+ for metabolic reactions. Excess is excreted in urine. Unlike niacin, niacinamide does not cause flushing.

Current Availability and Use
Niacinamide has been widely available in supplements and skin care products since the 1940s. It is used for cardiovascular support, skin health, and hair growth. Safe long-term use has been documented in clinical trials.

Clinical Features

• Hair growth: Improves scalp circulation and supports keratin synthesis, reducing thinning over 3–6 months.
• Skin barrier support: Enhances scalp hydration and lowers scalp irritation.
• Anti-inflammatory: Reduces oxidative stress and inflammation around follicles.
• DNA repair: Supports repair of UV-damaged cells, protecting hair and skin from environmental stress.
• Deficiency correction: Prevents pellagra-related hair loss and dermatitis.

Dosing
RDA: 14 mg daily for women, 16 mg for men. Hair and skin supplements often contain 15–30 mg of niacinamide. Available in capsules, tablets, multivitamins, and topical serums.

Safety
Niacinamide is generally safe. High doses above 500 mg/day may cause nausea or liver strain. Safe in pregnancy and breastfeeding within RDA. Safe in children with age-appropriate dosing. Niacinamide avoids the flushing effect caused by niacin.

Mechanism of Action

• NAD+/NADP+ production: Supports cellular energy needed for hair follicle growth.
• Improves circulation: Enhances blood flow to scalp and follicles.
• Anti-inflammatory: Lowers cytokines (IL-6, TNF-α) linked to follicle damage.
• Antioxidant defense: Reduces oxidative stress in scalp cells.
• Keratinocyte support: Improves scalp skin turnover and follicle structure.
  
  

Background
Biotin, also known as vitamin B7 or vitamin H, is a water-soluble B-vitamin that helps the body convert food into energy. It plays a key role in keratin production, the main protein in hair, skin, and nails. For this reason, biotin is one of the most popular nutrients used for hair strength and growth.

Origin, Source, and Traditional/Historical Use
Biotin is found naturally in foods such as eggs, nuts, seeds, and whole grains. Deficiency is rare but can cause brittle nails, skin rashes, and hair loss. Historically, egg yolks were considered beneficial for hair and skin, partly due to their high biotin content.

Key Active Compounds and Chemical Composition
Biotin (C10H16N2O3S) functions as a coenzyme for carboxylase enzymes, which are essential in fatty acid synthesis, amino acid metabolism, and glucose production. These processes supply energy and building blocks for growing hair follicles.

Bioavailability, Absorption, and Metabolism
Biotin is absorbed in the small intestine by sodium-dependent transporters. It circulates freely in blood and is stored in small amounts in the liver. D-biotin, the natural form, is highly bioavailable. Excess is excreted in urine, making toxicity rare.

Current Availability and Use
Biotin has been sold as a supplement for decades and is widely included in hair, skin, and nail formulas. It is available as capsules, tablets, and gummies. Long-term daily use has been shown to be safe.

Clinical Features

• Hair growth: Supports keratin structure, leading to thicker hair over 3–6 months.
• Deficiency correction: Restores hair growth in people with biotin deficiency.
• Nail strength: Improves brittle nails after 2–6 months of daily use.
• Skin health: Helps reduce rash and dryness linked to deficiency.
• Metabolic support: Aids energy metabolism, indirectly supporting healthy hair follicles.

Dosing
RDA: 30 mcg daily for adults. Hair supplements often contain 2,500–10,000 mcg (2.5–10 mg). Best absorbed with food. Available in capsules, tablets, powders, and gummies.

Safety
Biotin is very safe, even at high doses, because excess is excreted. No upper intake limit has been established. Main caution: very high doses can interfere with some lab tests (such as thyroid or heart markers). Safe in pregnancy and breastfeeding at RDA levels.

Mechanism of Action

• Keratin production: Activates keratin genes for stronger hair shafts.
• Fatty acid metabolism: Provides essential lipids for scalp and follicle health.
• Enzyme cofactor: Supports carboxylases involved in energy and amino acid metabolism.
• Gene regulation: Influences DNA expression in skin and hair cells.

Cell growth: Supports rapid turnover of follicle and nail cells.

Background
Iodine is an essential trace mineral needed for healthy thyroid function. The thyroid gland produces hormones (T3 and T4) that regulate metabolism, energy, and hair growth. Low iodine levels can lead to hair thinning, brittle hair, and shedding.

Origin, Source, and Traditional/Historical Use
Iodine is naturally found in seaweed, seafood, and iodized salt. Organic kelp (a type of seaweed) is one of the richest natural sources. Historically, coastal communities consuming seaweed had fewer thyroid problems compared to inland populations. Iodine-rich kelp has been used in traditional Asian medicine for thyroid and skin health.

Key Active Compounds and Chemical Composition
The active form is iodide (I−), which is taken up by the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3). Kelp also provides other minerals such as calcium, magnesium, and iron, which support overall health.

Bioavailability, Absorption, and Metabolism
Iodine from kelp is absorbed efficiently in the stomach and small intestine. It circulates in the blood as iodide and is concentrated in the thyroid. Excess iodine is excreted in urine. Bioavailability from kelp is high, though absorption may vary slightly depending on seaweed type.

Current Availability and Use
Iodine has been supplemented in diets since the early 20th century to prevent goiter. Organic kelp-based iodine supplements are widely available today. Long-term use within safe limits has been shown to support thyroid and hair health.

Clinical Features

• Hair growth: Correcting iodine deficiency improves hair regrowth within 3–6 months.
• Thyroid function: Maintains normal T3/T4 hormone levels that support follicle activity.
• Metabolism support: Ensures proper energy supply to scalp and hair roots.
• Deficiency prevention: Prevents goiter, fatigue, dry skin, and hair loss caused by low iodine.
• Skin and nail health: Supports keratin structure and hydration.

Dosing
RDA: 150 mcg/day for adults, 220–290 mcg/day in pregnancy and lactation. Hair and thyroid supplements often provide 150–300 mcg. Best taken with food. Available in capsules, tablets, and kelp powders.

Safety
Safe at recommended levels. Excess iodine (>1100 mcg/day) may cause thyroid imbalance (hypo- or hyperthyroidism). People with thyroid disorders should use caution and consult a doctor. Generally safe in pregnancy within RDA.

Mechanism of Action

• Thyroid hormone production: Iodide combines with tyrosine to form T3 and T4.
• Hair follicle stimulation: Thyroid hormones regulate follicle cycling and hair shaft growth.
• Cell metabolism: T3 increases energy production in follicle cells.
• Protein synthesis: Supports keratin production in hair and nails.
• Immune regulation: Prevents autoimmune thyroid inflammation that can cause hair loss.
  
  

Background
Zinc is an essential trace mineral needed for over 300 enzyme reactions in the body. It supports immune defense, skin health, and cell repair. For hair, zinc is critical for follicle growth, protein synthesis, and hormone balance. Deficiency often leads to hair loss, brittle hair, and delayed growth.

Origin, Source, and Traditional/Historical Use
Zinc is found in foods such as red meat, shellfish, beans, nuts, and whole grains. Since the 1960s, zinc supplements have been used to treat skin conditions, hair thinning, and delayed wound healing. Zinc picolinate, a highly absorbable form, is often used in modern supplements.

Key Active Compounds and Chemical Composition
Zinc picolinate is zinc bound to picolinic acid (C6H4NO2). This chelated form improves absorption compared to zinc oxide or sulfate. Once absorbed, zinc ions participate in enzyme reactions that regulate cell growth, DNA repair, and protein production.

Bioavailability, Absorption, and Metabolism
Zinc absorption occurs in the small intestine and is influenced by dietary factors. Zinc picolinate has higher bioavailability than other forms, as picolinic acid enhances uptake. Zinc is transported in blood bound to albumin and stored in muscles and bones. Excess zinc is excreted in feces.

Current Availability and Use
Zinc supplements have been on the market for decades. Zinc picolinate is a preferred form due to its superior absorption. It is widely available in capsules and tablets and often included in hair, skin, and nail formulas.

Clinical Features

• Hair loss prevention: Corrects zinc deficiency, improving hair regrowth within 3–6 months.
• Scalp health: Reduces dandruff and seborrheic dermatitis symptoms.
• Immune support: Maintains immune balance, reducing inflammation that can damage follicles.
• Wound healing: Speeds scalp and skin repair.
• Hormone regulation: Supports thyroid and sex hormones, both important for hair growth.

Dosing
RDA: 8 mg daily for women, 11 mg for men. Hair supplements usually provide 10–15 mg zinc picolinate. Best absorbed on an empty stomach but may be taken with food if stomach upset occurs.

Safety
Safe within RDA. Excess intake (>40 mg/day) may cause nausea, diarrhea, or copper deficiency. Safe in children at adjusted doses. Pregnant and breastfeeding women should not exceed 40 mg/day without medical supervision.

Mechanism of Action

• Enzyme cofactor: Supports enzymes for DNA and protein synthesis in follicles.
• Keratin production: Stimulates keratinocyte activity for strong hair shafts.
• Antioxidant defense: Stabilizes cell membranes and reduces oxidative stress.
• Immune regulation: Balances cytokines (IL-2, TNF-α) to protect follicles.
• Hormone support: Helps regulate thyroid and androgen activity linked to hair growth.
  
  

Background
Selenium is an essential trace mineral that protects cells from damage, supports thyroid health, and boosts immunity. For hair, selenium helps regulate follicle growth and prevents oxidative stress that can weaken hair strands.

Origin, Source, and Traditional/Historical Use
Selenium is naturally found in Brazil nuts, seafood, eggs, and whole grains. It was discovered in the early 19th century and later recognized as essential for health in the 1950s. Populations with selenium-rich diets were observed to have better immune function and healthier hair and skin.

Key Active Compounds and Chemical Composition
The supplement form L-selenomethionine is selenium bound to the amino acid methionine (C5H11NO2Se). This organic form is highly bioavailable and easily incorporated into body proteins, serving as a reservoir of selenium.

Bioavailability, Absorption, and Metabolism
L-selenomethionine is absorbed in the small intestine using the same pathways as methionine. It is stored in tissues such as the liver, muscles, and hair follicles. Selenium is later released and converted into selenoproteins, which act as antioxidant enzymes.

Current Availability and Use
Selenium supplements have been available since the 1970s, with L-selenomethionine considered one of the most effective and safe forms. It is widely used in multivitamins and hair, skin, and nail formulas.

Clinical Features

• Hair health: Selenium deficiency has been linked to hair loss, which improves when levels are corrected over 3–6 months.
• Antioxidant defense: As part of glutathione peroxidase, selenium reduces free radical damage in scalp and follicle cells.
• Thyroid function: Supports production of thyroid hormones (T3 and T4) that regulate follicle cycling.
• Immune support: Enhances immune balance, reducing autoimmune conditions that may trigger hair loss.
• Scalp health: Works with zinc to control dandruff-causing fungi.

Dosing
RDA: 55 mcg daily for adults; 60–70 mcg in pregnancy and breastfeeding. Hair supplements often provide 50–200 mcg. Best taken with food for improved absorption.

Safety
Safe at recommended levels. Excess intake (>400 mcg/day) may cause selenosis, with symptoms like brittle nails, hair loss, and digestive upset. Safe in children at adjusted doses. Pregnant women should avoid high doses.

Mechanism of Action

• Selenoprotein activity: Forms part of antioxidant enzymes (glutathione peroxidase, thioredoxin reductase)
• Thyroid hormone metabolism: Converts T4 into active T3, regulating hair follicle function.
• Immune regulation: Balances inflammatory cytokines, protecting follicles.
• Keratin protection: Prevents oxidative damage to hair proteins.
• Antifungal effects: Helps reduce dandruff by inhibiting Malassezia growth.
  
  

Background
Amla, also known as Indian gooseberry (Emblica officinalis or Phyllanthus emblica), is a fruit long used in Ayurvedic medicine. It is rich in vitamin C, antioxidants, and polyphenols that support hair, skin, and overall health. For hair, amla is known to strengthen follicles, promote growth, and prevent premature graying.

Origin, Source, and Traditional/Historical Use
Amla trees are native to India and Southeast Asia. In Ayurveda, amla has been used for over 3,000 years as a “rasayana,” or rejuvenating herb, for longevity and vitality. Traditionally, amla oil and powders were applied to the scalp to thicken hair and improve shine.

Key Active Compounds and Chemical Composition
Amla fruit contains high levels of vitamin C, tannins (emblicanin A and B), gallic acid, ellagic acid, and flavonoids. These compounds provide antioxidant, anti-inflammatory, and hair-nourishing effects.

Bioavailability, Absorption, and Metabolism
Vitamin C and polyphenols from amla are absorbed in the small intestine. Once in circulation, they reduce oxidative stress and support collagen formation. Amla tannins help stabilize vitamin C, allowing longer-lasting antioxidant effects compared to citrus fruits.

Current Availability and Use
Amla is widely used in dietary supplements, hair oils, and powders across Asia and globally. It is included in many hair formulas for growth and scalp health. Human studies support safe daily use for up to 6 months.

• Hair growth: Animal and human studies show increased hair density and thickness after 3–6 months.
• Anti-graying: Antioxidants protect hair follicles from oxidative stress linked to premature graying.
• Scalp health: Reduces dandruff, itching, and scalp inflammation.
• Collagen support: High vitamin C strengthens connective tissues around hair roots.
• Immune function: Boosts immunity, indirectly supporting hair growth during stress or illness.
  
  

Background
Bhringraj (Eclipta alba), also called “False Daisy,” is a traditional Ayurvedic herb best known for promoting strong hair and preventing premature graying. It is called the “king of hair” in Ayurveda because of its powerful effects on scalp health and hair growth.

Origin, Source, and Traditional/Historical Use
Bhringraj grows in India, China, Thailand, and other tropical regions. For centuries, its leaves have been used in Ayurveda for liver health, skin conditions, and especially for hair oils and pastes. Traditional use included applying bhringraj oil to the scalp to thicken hair and prevent shedding.

Key Active Compounds and Chemical Composition
Bhringraj contains wedelolactone, ecliptine, flavonoids, and phytosterols. These compounds have antioxidant, anti-inflammatory, and hair follicle–stimulating properties.

Bioavailability, Absorption, and Metabolism
When taken orally, wedelolactone and flavonoids are absorbed in the small intestine and metabolized in the liver. Topical application delivers compounds directly to the scalp, where they act on follicles. Animal studies confirm both oral and topical bioactivity.

Current Availability and Use
Bhringraj is available as extracts, capsules, teas, and hair oils. It has been marketed in India and Asia for centuries and is now popular worldwide in natural hair care formulas.

Clinical Features

• Hair growth: Animal studies show faster follicle regrowth compared to minoxidil after 30 days.
  
  
• Anti-graying: Protects pigment cells (melanocytes), delaying premature graying.
  
  
• Scalp health: Reduces dandruff and itching due to antifungal and anti-inflammatory activity.
  
  
• Stress-related hair loss: Adaptogenic effects help reduce shedding linked to stress.
  
  
• Liver support: Traditional use improves detoxification, indirectly supporting healthy hair.
  
  

Dosing
Typical oral dose: 250–500 mg extract daily. Topical application: bhringraj oil massaged into the scalp several times per week. Available in capsules, powders, oils, and teas.

Safety
Bhringraj is generally safe. Mild side effects may include stomach upset when taken in large doses. Safe for topical use in most people. Avoid use in pregnancy unless under medical guidance.

Mechanism of Action

• Hair follicle stimulation: Wedelolactone promotes follicle growth phase (anagen).
  
  
• Melanin support: Protects melanocytes, delaying graying.
  
  
• Anti-inflammatory: Reduces scalp inflammation by lowering cytokines (IL-6, TNF-α).
  
  
• Antioxidant defense: Neutralizes free radicals in scalp tissues.
  
  
• Antimicrobial action: Inhibits fungi and bacteria linked to dandruff.
  
  

Background
Black pepper (Piper nigrum) is a common spice with strong medicinal value. Its main active compound, piperine, is known for improving nutrient absorption, boosting metabolism, and providing antioxidant support. In hair health supplements, black pepper extract enhances the bioavailability of vitamins, minerals, and herbs that promote stronger hair growth.

Origin, Source, and Traditional/Historical Use
Native to India, black pepper has been used in Ayurvedic and traditional Chinese medicine for thousands of years to improve digestion, circulation, and overall vitality. Historically, it was valued as “black gold” in trade. Modern extracts standardize piperine at 95% for consistent effects.

Key Active Compounds and Chemical Composition
The key compound is piperine (C17H19NO3). Piperine is an alkaloid responsible for pepper’s pungency and its bioenhancing effects. It works by slowing down drug-metabolizing enzymes and increasing nutrient absorption in the gut.

Bioavailability, Absorption, and Metabolism
Piperine is absorbed in the intestine and rapidly reaches the bloodstream. It inhibits liver enzymes (CYP3A4, P-glycoprotein), which normally break down nutrients and drugs. This allows higher blood levels of vitamins, minerals, and herbal compounds. Its half-life is about 6 hours.

Current Availability and Use
Black pepper extract with standardized piperine has been sold as a supplement since the 1990s. It is commonly added to multivitamins, herbal formulas, and hair and skin products to increase effectiveness of other ingredients.

Clinical Features

• Nutrient absorption: Piperine boosts absorption of vitamin C, vitamin D, selenium, and beta-carotene by 30–200%.
• Hair growth support: By improving bioavailability, piperine enhances delivery of hair nutrients such as biotin, zinc, and amla.
• Antioxidant defense: Reduces oxidative stress in scalp tissues and protects follicles.
• Anti-inflammatory effects: Lowers inflammatory cytokines linked to scalp irritation.
• Metabolic support: Improves circulation and thermogenesis, indirectly supporting follicle activity.

Dosing
Typical dose: 5–10 mg standardized piperine daily, often combined with vitamins and herbs. Available as capsules, tablets, and included in complex supplements.

Safety
Piperine is generally safe at recommended doses. High doses may cause stomach upset or interact with certain medications by raising drug levels. Avoid during pregnancy unless advised by a doctor. Safe for adults and children at low supplemental levels.

Mechanism of Action

• Enzyme inhibition: Blocks CYP3A4 and P-glycoprotein, slowing nutrient breakdown.
• Enhanced absorption: Increases intestinal permeability to vitamins and minerals.
• Antioxidant action: Neutralizes free radicals in scalp and hair follicles.
• Anti-inflammatory activity: Reduces NF-κB pathway activation, lowering inflammation.
• Circulatory effects: Stimulates blood flow, supporting nutrient delivery to follicles.
  
  

Background
Curcumin is the main active compound in turmeric (Curcuma longa), a yellow root widely used as a spice and medicine. It is well known for its antioxidant and anti-inflammatory properties. For hair, curcumin supports follicle health, reduces scalp inflammation, and may help slow hair thinning.

Origin, Source, and Traditional/Historical Use
Turmeric has been used in Indian and Chinese medicine for over 2,000 years to treat wounds, digestive problems, and skin conditions. In Ayurveda, turmeric was also applied to the scalp to promote strong, shiny hair. Today, curcumin is extracted and standardized for use in supplements.

Key Active Compounds and Chemical Composition
Turmeric contains curcuminoids—curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Curcumin (C21H20O6) is the most studied. It gives turmeric its bright color and healing effects.

Bioavailability, Absorption, and Metabolism
Curcumin is absorbed in the gut but has low natural bioavailability. When combined with piperine (from black pepper), absorption increases by up to 2000%. Once absorbed, it is metabolized in the liver and distributed to tissues, including the scalp.

Current Availability and Use
Curcumin extracts have been sold worldwide since the 1990s in capsules, tablets, and functional foods. It is commonly added to joint, brain, skin, and hair supplements.

Clinical Features

• Anti-inflammatory effects: Curcumin lowers scalp inflammation and may reduce hair loss linked to stress or autoimmune conditions
• Antioxidant defense: Protects follicles from oxidative stress, a key factor in hair thinning.
• Hormonal balance: Animal studies suggest curcumin may reduce excess DHT, a hormone linked to pattern hair loss.
• Wound and scalp healing: Supports faster healing of scalp irritation and dandruff.
• Immune support: Helps balance immune activity, protecting follicles from overactive immune attacks.
  
  

Dosing
Typical oral dose: 500–1000 mg daily of standardized curcumin, often combined with piperine for absorption. Available in capsules, tablets, teas, and topical creams.

Safety
Curcumin is generally safe. High doses may cause mild stomach upset or diarrhea. Safe for long-term use at recommended levels. Pregnant women should consult a healthcare provider before high-dose supplementation.

Mechanism of Action

• NF-κB pathway inhibition: Reduces inflammatory signaling in scalp tissues.
• Antioxidant activity: Boosts enzymes like superoxide dismutase and catalase to fight free radicals.
• DHT modulation: May lower 5-alpha reductase activity, reducing hair loss risk.
• Immune regulation: Balances cytokines (IL-6, TNF-α), protecting follicles.
• Stem cell support: Encourages follicle stem cells to enter growth phase (anagen).
  
  

Background
Ginkgo biloba is one of the oldest living tree species, often called a “living fossil.” Extracts from its leaves are widely used to improve circulation, memory, and brain health. For hair, ginkgo supports scalp blood flow, reduces oxidative stress, and helps protect follicles from damage.

Origin, Source, and Traditional/Historical Use
Native to China, ginkgo has been used in traditional medicine for over 2,000 years. Ancient texts describe it as a remedy for asthma, cough, and brain health. Today, standardized ginkgo leaf extracts (containing 24% flavone glycosides and 6% terpene lactones) are among the most researched herbal supplements worldwide.

Key Active Compounds and Chemical Composition
The main compounds are flavonoids (quercetin, kaempferol, isorhamnetin) and terpene lactones (ginkgolides A, B, C, and bilobalide). These provide antioxidant, anti-inflammatory, and circulation-boosting effects.

Bioavailability, Absorption, and Metabolism
Ginkgo flavonoids are absorbed in the small intestine and circulate in the bloodstream within 1–2 hours. Terpene lactones cross the blood–brain barrier, improving microcirculation. Compounds are mainly metabolized in the liver and excreted through urine.

Current Availability and Use
Standardized ginkgo extract (24%) has been sold worldwide since the 1960s. It is widely available in capsules, tablets, and liquid extracts. It is often combined with other nutrients in formulas for brain, vision, and hair health.

Clinical Features

• Scalp circulation: Human studies show ginkgo improves peripheral blood flow by 20–30%, supporting follicle nourishment.
• Hair growth: Animal studies report thicker and denser hair after 6–8 weeks of extract use.
• Antioxidant defense: Reduces oxidative stress markers (MDA levels) in scalp tissues.
• Anti-inflammatory: Suppresses pro-inflammatory cytokines that can damage follicles.
• Cognitive and stress support: By improving mental focus and reducing stress, ginkgo indirectly benefits hair health.

Dosing
Typical daily dose: 120–240 mg standardized extract (24%) divided into 2–3 doses. Often taken with meals for better absorption.

Safety
Generally safe at recommended doses. Side effects are mild and may include stomach upset or headache. Avoid use with blood thinners due to increased bleeding risk. Pregnant women should consult a doctor before use.

Mechanism of Action

• Vasodilation: Increases nitric oxide, improving scalp blood circulation.
• Antioxidant activity: Neutralizes free radicals with flavonoids.
• Neuroprotection: Terpene lactones protect nerve and follicle cells from oxidative damage.
• Anti-inflammatory: Inhibits NF-κB pathway, lowering scalp inflammation.
• Mitochondrial support: Improves energy production in follicle cells.
  
  

Background
Grape seed extract comes from the small seeds of grapes and is rich in antioxidants called proanthocyanidins. These compounds are powerful protectors against free radicals, which damage cells and speed up aging. For hair, grape seed extract helps protect follicles, improves scalp circulation, and supports stronger, healthier growth.

Origin, Source, and Traditional/Historical Use
Grapes have been used in Mediterranean diets and medicine for thousands of years. Ancient Greeks and Egyptians valued grapes for health and healing. Modern grape seed extract is standardized to 95% proanthocyanidins, giving it strong antioxidant activity much higher than vitamins C and E.

Key Active Compounds and Chemical Composition
The main compounds are oligomeric proanthocyanidins (OPCs), along with catechins, gallic acid, and resveratrol. OPCs are known for improving circulation, protecting collagen, and supporting skin and hair health.

Bioavailability, Absorption, and Metabolism
Proanthocyanidins are absorbed in the small intestine, with peak plasma levels seen within 2 hours. They are metabolized in the liver and excreted in urine. Studies show grape seed polyphenols cross into tissues, including skin and scalp.

Current Availability and Use
Standardized grape seed extract (95% OPCs) has been sold worldwide since the 1980s. It is widely available in capsules, tablets, and functional drinks. It is commonly used in supplements for circulation, skin, and hair.

Clinical Features

• Hair growth: Animal studies show OPCs stimulate hair follicles and improve hair density within 4–6 weeks.
• Circulation support: Increases scalp blood flow, delivering nutrients to follicles.
• Antioxidant protection: OPCs are 20x stronger than vitamin C in neutralizing free radicals.
• Collagen support: Protects and strengthens collagen in scalp tissues, supporting follicle anchoring.
• Skin and scalp health: Reduces oxidative stress and irritation linked to dandruff and inflammation.

Dosing
Typical dose: 100–300 mg standardized grape seed extract daily. Available as capsules, tablets, powders, and combined formulas.

Safety
Generally safe at recommended doses. Mild side effects may include nausea or headache. Safe for long-term use. Pregnant and breastfeeding women should consult a doctor before use.

Mechanism of Action

• Antioxidant defense: Neutralizes free radicals with OPCs.
  
  
• Vasodilation: Enhances nitric oxide production, improving scalp circulation.
  
  
• Collagen stabilization: Protects collagen and elastin in follicle structures.
  
  
• Anti-inflammatory: Inhibits NF-κB signaling, lowering cytokines.
  
  
• Follicle stimulation: Encourages follicle stem cells into active growth phase (anagen).
  
  

Background
Green tea comes from the leaves of the Camellia sinensis plant and is rich in natural antioxidants called catechins. The most powerful is epigallocatechin gallate (EGCG), which protects cells, improves circulation, and supports healthy hair growth. For hair, EGCG may reduce hormone-driven thinning and protect follicles from stress and damage.

Origin, Source, and Traditional/Historical Use
Green tea has been used in China and Japan for over 4,000 years as a daily drink and medicine. Traditionally, it was valued for boosting energy, digestion, and longevity. Today, standardized extracts with 45% EGCG are widely used in supplements for metabolism, skin, and hair health.

Key Active Compounds and Chemical Composition
The main compounds are catechins, especially EGCG, along with epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin (EGC). EGCG is the strongest antioxidant, giving green tea its health benefits.

Bioavailability, Absorption, and Metabolism
EGCG is absorbed in the small intestine, with peak levels seen in blood within 1–2 hours. Its absorption improves when taken without food. It is metabolized in the liver and excreted in urine. Studies show it can reach skin and scalp tissues.

Current Availability and Use
Green tea extract has been sold as a supplement since the 1990s. It is available in capsules, tablets, teas, and powders. It is often added to formulas for weight, skin, and hair health.

Clinical Features

• Hair growth support: Animal studies show EGCG stimulates follicles and prolongs the hair growth (anagen) phase.
  
  
• Hormonal balance: Human and lab studies suggest EGCG reduces activity of 5-alpha reductase, an enzyme that produces DHT, a hormone linked to hair loss.
  
  
• Antioxidant defense: EGCG reduces oxidative stress and lowers markers of scalp damage.
  
  
• Anti-inflammatory effects: Inhibits cytokines and pathways that inflame hair follicles.
  
  
• Circulation improvement: Catechins enhance blood vessel relaxation, improving nutrient delivery to follicles.
  
  

Dosing
Typical daily dose: 250–500 mg standardized green tea extract (45% EGCG). Best taken in the morning or early afternoon. Available as capsules, tablets, and teas.

Safety
Generally safe at recommended doses. High intakes may cause stomach upset or, rarely, liver irritation. Pregnant and breastfeeding women should consult a doctor before use. Avoid taking late in the evening due to mild caffeine content.

Mechanism of Action

• 5-alpha reductase inhibition: Lowers DHT, reducing hair follicle shrinkage.
• Antioxidant action: Neutralizes free radicals, protecting scalp cells.
• Anti-inflammatory: Blocks NF-κB and COX-2 pathways, lowering inflammation.
• Cell cycle regulation: Encourages follicle stem cells to stay in growth phase.
• Vasodilation: Boosts nitric oxide, improving scalp blood flow.
  
  

Background
Horsetail (Equisetum arvense) is an ancient plant that has existed for over 100 million years. It is well known for its high mineral content, especially silica, which supports hair, skin, and nail strength. In hair health, horsetail extract may improve shine, reduce breakage, and support stronger follicle growth.

Origin, Source, and Traditional/Historical Use
Native to Europe, Asia, and North America, horsetail has been used in traditional medicine for centuries. Ancient Romans and Greeks used it to stop bleeding, heal wounds, and strengthen bones. In folk remedies, it was brewed as tea to improve hair and nail health. Today, standardized extracts are used in supplements.

Key Active Compounds and Chemical Composition
The main compounds are silica (up to 25% of dry weight), flavonoids (quercetin, kaempferol), phenolic acids, and small amounts of alkaloids. Silica is the key mineral linked to stronger connective tissue and follicle support.

Bioavailability, Absorption, and Metabolism
Silica from horsetail is absorbed in the small intestine and enters the bloodstream as orthosilicic acid. It is then used in collagen and keratin production in skin, hair, and nails. Excess is excreted in urine.

Current Availability and Use
Horsetail extract is widely available in capsules, tablets, and teas. It is often included in beauty formulas for hair, skin, and nails.

Clinical Features

• Hair strength: A small clinical trial showed reduced hair breakage and stronger strands after 90 days of horsetail extract.
• Shine and thickness: Users reported shinier and denser hair with regular use.
• Collagen support: Animal studies suggest horsetail boosts collagen formation in connective tissues.
• Mineral support: Provides natural silica to support keratin, the protein that builds hair.
• Nail and skin benefits: Improves nail hardness and skin elasticity, indirectly supporting hair health.z

Dosing
Common dose: 300–600 mg daily of standardized horsetail extract. Often taken in capsule or tablet form, though teas are also used.

Safety
Generally safe when standardized for use. Raw horsetail can contain thiaminase, which breaks down vitamin B1, but commercial extracts are processed to remove this risk. Not recommended for people with kidney disease. Pregnant and breastfeeding women should consult a doctor before use.

Mechanism of Action

• Silica delivery: Provides silica for keratin and collagen synthesis in follicles.
• Antioxidant effects: Flavonoids reduce oxidative stress in scalp tissues
• Collagen stimulation: Supports structural proteins in skin and follicles.
• Anti-inflammatory action: Lowers cytokines that damage follicle health.
• Vascular support: Mild diuretic effect may improve circulation and nutrient delivery.
  
  

Background
L-Cysteine is a sulfur-containing amino acid that plays an important role in building proteins, especially keratin, the main protein in hair, skin, and nails. It is considered a “semi-essential” amino acid because the body can make some, but extra from diet or supplements may improve hair health.

Origin, Source, and Traditional/Historical Use
L-Cysteine is found naturally in protein-rich foods like eggs, poultry, dairy, legumes, and seeds. While not a traditional medicine, foods rich in cysteine were long recognized for supporting strength, vitality, and healthy growth of hair and nails.

Key Active Compounds and Chemical Composition
L-Cysteine (C3H7NO2S) contains a thiol (-SH) group, which gives it antioxidant activity and allows it to form disulfide bonds. These bonds are critical for the strong structure of keratin in hair.

Bioavailability, Absorption, and Metabolism
L-Cysteine is absorbed in the small intestine and transported to tissues through the bloodstream. It can be converted into glutathione, one of the body’s most powerful antioxidants, which protects hair follicles from damage. Excess amounts are broken down in the liver.

Current Availability and Use
L-Cysteine has been available as a dietary supplement since the 1970s. It is often included in hair, skin, and nail formulas because of its keratin-boosting effects. It is also used in some medications and as a food additive.

Clinical Features

• Keratin production: Strengthens hair shafts by supporting keratin protein bonds.
• Hair growth: Studies show cysteine, when combined with other nutrients, improves hair density and thickness within 3–6 months.
• Antioxidant defense: Through glutathione, cysteine protects follicles from oxidative stress.
• Nail and skin benefits: Strengthens nails and supports healthy skin turnover.
• Deficiency correction: Prevents brittle, weak hair linked to low sulfur amino acids.

Dosing
Typical supplemental dose: 200–500 mg daily, often provided as N-acetyl-L-cysteine (NAC) for better stability. Best taken with meals. Available in capsules, tablets, and combined hair health formulas.

Safety
Generally safe at recommended doses. High doses (>1000 mg/day) may cause nausea, diarrhea, or abdominal pain. Not recommended for people with cystinuria, a rare kidney condition. Safe in pregnancy and breastfeeding when consumed from normal diet levels.

Mechanism of Action

• Keratin structure: Forms disulfide bonds that give hair shafts strength and elasticity.
• Glutathione precursor: Boosts glutathione levels, reducing oxidative stress in follicles.
• Collagen support: Contributes sulfur for connective tissue proteins.
• Detoxification: Helps bind and remove toxins that may damage scalp tissues.
• Cellular protection: Maintains redox balance in rapidly growing follicle cells.

Rosemary (Rosmarinus officinalis) is a fragrant Mediterranean herb known for its culinary and medicinal uses. As an extract, rosemary is valued for its antioxidant, anti-inflammatory, and circulation-boosting effects. For hair, it is used to stimulate growth, strengthen follicles, and reduce scalp irritation.

Origin, Source, and Traditional/Historical Use
Rosemary has been used for more than 2,000 years in Europe, North Africa, and Asia. Ancient Greeks and Romans used it for memory and vitality, while traditional medicine applied rosemary oil to the scalp to thicken hair and prevent dandruff. Today, standardized rosemary leaf extract is widely used in supplements and topical hair products.

Key Active Compounds and Chemical Composition
Rosemary extract contains rosmarinic acid, carnosic acid, carnosol, and essential oils such as cineole and camphor. These compounds provide strong antioxidant and antimicrobial effects while supporting circulation.

Bioavailability, Absorption, and Metabolism
Rosmarinic acid and carnosic acid are absorbed in the intestine and circulate in the blood within 1–2 hours. They are metabolized in the liver and excreted mainly in urine. Studies show these compounds reach skin and hair follicles, where they exert protective effects.

Current Availability and Use
Rosemary leaf extract is sold globally in capsules, tablets, tinctures, teas, and hair oils. Clinical and animal studies support its role in hair regrowth and scalp health, making it popular in modern hair supplements.

Clinical Features

• Hair regrowth: A human study found rosemary oil applied for 6 months improved hair count as effectively as 2% minoxidil in people with androgenetic alopecia.
• Scalp circulation: Enhances blood flow to follicles, improving nutrient delivery.
• Anti-dandruff: Antifungal activity reduces Malassezia, a fungus linked to dandruff.
• Antioxidant support: Lowers oxidative stress in follicles, protecting against thinning.
• Anti-inflammatory: Soothes scalp irritation and reduces redness.

Dosing
Typical oral dose: 250–500 mg standardized extract daily. Topical use: diluted rosemary oil applied to the scalp 2–3 times weekly. Available as capsules, teas, tinctures, and oils.

Safety
Rosemary extract is generally safe. High oral doses may cause stomach upset. Essential oil should always be diluted before topical use. Not recommended in pregnancy at high doses due to possible uterine stimulation. Safe in children at dietary levels.

Mechanism of Action

• Circulation boost: Increases nitric oxide and vasodilation, improving follicle nutrition.
• Antioxidant action: Neutralizes ROS (reactive oxygen species) that damage follicles.
• Anti-androgen effect: Inhibits 5-alpha reductase, reducing DHT levels linked to hair loss.
• Antimicrobial: Fights bacteria and fungi that irritate the scalp.
• Anti-inflammatory: Blocks NF-κB pathway, lowering inflammatory markers.

Background
Saw palmetto (Serenoa repens) is a small palm native to the southeastern United States. Its berries have long been used for urinary and reproductive health. Today, saw palmetto extract is also valued for supporting hair health, especially in reducing hormone-related hair loss.

Origin, Source, and Traditional/Historical Use
Native American tribes, such as the Seminoles, traditionally ate saw palmetto berries to boost strength, treat urinary problems, and support reproductive health. In modern times, the extract has become popular for prostate support and, more recently, for hair growth formulas.

Key Active Compounds and Chemical Composition
The main active compounds are fatty acids (lauric, oleic, and linoleic acids) and phytosterols (beta-sitosterol, stigmasterol). These compounds are thought to reduce the activity of 5-alpha reductase, the enzyme that converts testosterone into dihydrotestosterone (DHT), a hormone strongly linked to hair thinning.

Bioavailability, Absorption, and Metabolism
Saw palmetto’s fatty acids are absorbed in the small intestine and carried in the bloodstream bound to lipoproteins. Standardized extracts (4:1 concentration) provide consistent levels of active compounds. The body metabolizes them in the liver, and they are excreted through bile and urine.

Current Availability and Use
Saw palmetto supplements have been widely available since the 1990s, mostly in prostate and men’s health products. It is now included in many hair growth and anti-thinning formulas for both men and women.

Clinical Features

• Hormonal hair loss: Human studies show saw palmetto improves hair density and count after 24 weeks, particularly in androgenetic alopecia.
• DHT reduction: Supplementation lowered scalp DHT levels by up to 32% in some trials.
• Hair quality: Users reported thicker, stronger hair within 4–6 months of daily use.
• Scalp health: Anti-inflammatory effects help reduce irritation and support follicle function.
• Comparative studies: While not as strong as finasteride (a prescription DHT blocker), saw palmetto shows mild to moderate benefits with fewer side effects.

Dosing
Typical oral dose: 160–320 mg daily of standardized extract, often divided into 2 doses. Available in capsules, tablets, oils, and softgels.

Safety
Generally safe at recommended doses. Mild side effects may include stomach upset or headache. Rare reports of dizziness. Not recommended in pregnancy or breastfeeding. May interact with blood thinners or hormone therapies.

Mechanism of Action

• 5-alpha reductase inhibition: Lowers DHT production in scalp tissues.
• Anti-androgen effect: Reduces DHT binding to hair follicle receptors.
• Anti-inflammatory: Lowers cytokines (IL-6, TNF-α) that damage follicles.
• Circulation support: Fatty acids improve blood flow and follicle nourishment.

Antioxidant activity: Protects follicle cells from oxidative stress.

Background
Spirulina (Arthrospira platensis) is a blue-green algae known as a nutrient-dense “superfood.” It is packed with protein, vitamins, minerals, and antioxidants. For hair, spirulina provides amino acids for keratin, iron for follicle strength, and antioxidants to protect against damage and thinning.

Origin, Source, and Traditional/Historical Use
Spirulina grows naturally in alkaline lakes in Africa, Asia, and Central America. The Aztecs harvested spirulina from Lake Texcoco, using it as a protein-rich food. In Africa, people near Lake Chad have eaten spirulina cakes for centuries. Today, it is cultivated worldwide in freshwater farms.

Key Active Compounds and Chemical Composition
Spirulina contains ~60–70% protein, rich in all essential amino acids. It also provides iron, B vitamins, beta-carotene, phycocyanin (a blue antioxidant pigment), gamma-linolenic acid (GLA), and trace minerals like zinc and magnesium—all vital for hair health.

Bioavailability, Absorption, and Metabolism
Nutrients in spirulina are highly bioavailable. Its proteins and vitamins are easily digested, and phycocyanin is absorbed into the bloodstream where it exerts antioxidant and anti-inflammatory effects. Iron from spirulina is well absorbed and supports oxygen delivery to follicles.

Current Availability and Use
Spirulina has been sold as a supplement since the 1970s and is recognized by the World Health Organization as a valuable food source. It is available in powders, tablets, capsules, and smoothies.

Clinical Features

• Hair growth support: Provides amino acids and iron needed for keratin and follicle activity.
• Anti-thinning: Corrects iron deficiency, which is a common cause of hair shedding.
• Antioxidant protection: Phycocyanin reduces oxidative stress that damages scalp and follicles.
• Anti-inflammatory: Helps calm scalp irritation and dandruff.

Nutrient boost: Supplies essential vitamins (B12, A, E) linked to stronger, shinier hair.

Dosing
Common daily dose: 1–3 g for general health; up to 5–8 g for therapeutic use. Available as powders, tablets, and capsules.

Safety
Generally safe and well tolerated. Mild digestive upset may occur in sensitive individuals. Should be sourced from safe, uncontaminated waters to avoid heavy metals or toxins. Safe for most adults, but pregnant and breastfeeding women should consult a doctor before high-dose use.

Mechanism of Action

• Keratin support: Supplies amino acids for building hair protein.
• Iron delivery: Enhances hemoglobin and oxygen supply to follicles.
• Antioxidant defense: Phycocyanin neutralizes ROS (reactive oxygen species).
• Immune balance: Reduces inflammation through cytokine regulation.
• Scalp nourishment: Provides essential fatty acids and micronutrients for follicle health.

Background
Lactobacillus plantarum (UALp-05) is a well-studied probiotic strain that supports gut, immune, and skin health. It is known for its ability to survive stomach acid, colonize the intestines, and produce compounds that improve digestion and lower inflammation. For hair, L. plantarum may reduce stress, improve nutrient absorption, and create a healthier environment for follicle growth.

Origin, Source, and Traditional/Historical Use
L. plantarum occurs naturally in fermented foods like sauerkraut, pickles, kimchi, and sourdough. Cultures that consumed these foods regularly often enjoyed better gut and skin health. UALp-05 is a specific, clinically tested strain developed for supplements.

Key Active Compounds and Chemical Composition
This probiotic produces lactic acid, antimicrobial peptides, and short-chain fatty acids (SCFAs). These compounds strengthen the gut barrier, fight harmful microbes, and regulate immune and stress pathways that influence scalp and hair health.

Bioavailability, Absorption, and Metabolism
After ingestion, UALp-05 survives stomach acid and temporarily colonizes the intestines. It interacts with gut cells, producing SCFAs and signaling molecules that travel through the bloodstream. Its effects continue as long as supplementation is maintained.

Current Availability and Use
UALp-05 is widely used in probiotic blends for digestive, immune, and skin support. It is included in capsules, powders, and multi-strain probiotic products.

Clinical Features

• Gut health: Improves digestion and absorption of nutrients like iron and zinc, which are key for hair growth.
• Immune balance: Lowers inflammatory cytokines (IL-6, TNF-α) within 6–8 weeks.
• Stress support: Probiotic supplementation reduced cortisol levels by ~18% in clinical studies, which may help prevent stress-related hair loss.
• Skin and scalp health: Improves barrier function, reducing dryness and irritation.
• Hair connection: Animal studies show probiotics like L. plantarum increase hair density and thickness.

Dosing
Typical dose: 10–20 billion CFU daily. Best taken with food for improved survival through the stomach. Available in capsules, powders, and multi-strain blends.

Safety
Generally safe for adults and children. May cause mild gas or bloating in the first few days. Safe during pregnancy and breastfeeding. Use caution in severely immunocompromised individuals.

Mechanism of Action

• Gut–hair axis: Improves absorption of vitamins and minerals needed for follicles.
• SCFA production: Creates butyrate and acetate, which lower inflammation.
• Immune modulation: Increases regulatory T cells and reduces inflammatory cytokines.
• Stress reduction: Produces metabolites that influence the gut–brain axis, lowering cortisol.

Microbiome balance: Competes with harmful bacteria and restores healthy gut flora.

Background
Lactobacillus reuteri (UALre-16) is a probiotic strain naturally found in the human gut, breast milk, and oral cavity. It is one of the most studied probiotics for immune balance, skin health, and hormone support. For hair, L. reuteri helps through its effects on the gut–skin–hair axis by reducing inflammation, enhancing nutrient absorption, and influencing hormones associated with hair growth.

Origin, Source, and Traditional/Historical Use
First discovered in the 1960s, L. reuteri is naturally present in healthy breastfed infants and is also found in fermented foods. While not used traditionally as an isolated probiotic, cultures that consumed fermented foods containing L. reuteri experienced improved digestive and skin health.

Key Active Compounds and Chemical Composition
L. reuteri produces lactic acid, short-chain fatty acids (SCFAs), reuterin (an antimicrobial compound), and bioactive peptides. These regulate the gut microbiome, support immunity, and influence systemic processes like inflammation and hormone regulation.

Bioavailability, Absorption, and Metabolism
UALre-16 survives stomach acid and temporarily colonizes the intestines. Its metabolites, including reuterin and SCFAs, are absorbed and circulate throughout the body, where they impact immune balance, oxidative stress, and hormone activity.

Current Availability and Use
UALre-16 is available in probiotic supplements worldwide, often included in blends for digestive, skin, and immune health. Clinical studies show benefits for skin clarity, hormone balance, and overall well-being.

Clinical Features

• Hair growth link: Animal studies show L. reuteri increases hair follicle number and thickness, with visible improvements in 8–12 weeks.
• Hormone support: Helps balance testosterone and estrogen, both important for hair cycle regulation.
• Anti-inflammatory: Reduces systemic inflammation, protecting scalp follicles from damage.
• Immune balance: Increases anti-inflammatory cytokines and lowers harmful bacteria in the gut.
• Skin benefits: Human studies show reduced acne and better skin hydration, indirectly supporting scalp health.

Dosing
Typical daily dose: 1–10 billion CFU. Often found in capsules or multi-strain probiotic blends. Best taken with food for improved survival through the digestive tract.

Safety
Generally safe for adults and children. Mild digestive changes (gas, bloating) may occur at first. Safe in pregnancy and breastfeeding. Caution in severely immunocompromised individuals.

Mechanism of Action

• Gut–hair axis: Improves nutrient absorption (iron, zinc, biotin) for hair growth.
• Reuterin production: Inhibits harmful bacteria, restoring microbiome balance.
• SCFA activity: Produces butyrate and acetate, lowering inflammation and oxidative stress.
• Hormonal regulation: Modulates sex hormone pathways associated with the hair cycle.

Immune modulation: Shifts cytokine balance toward anti-inflammatory profiles (↑IL-10, ↓TNF-α).

Background
Lactobacillus rhamnosus (UALr-06) is a clinically studied probiotic strain known for its strong survival in the digestive system. It is widely researched for digestive, immune, and skin benefits. For hair, this strain supports the gut–skin–hair axis by improving nutrient absorption, lowering stress and inflammation, and supporting a healthier scalp environment.

Origin, Source, and Traditional/Historical Use
L. rhamnosus was first identified in the 1980s and has since become one of the most commonly used probiotics in supplements. While not used in ancient medicine, foods containing natural probiotics like yogurt, kefir, and fermented vegetables were long recognized for improving digestion and vitality. UALr-06 is a carefully selected, standardized strain for supplement use.

Key Active Compounds and Chemical Composition
This strain produces lactic acid, bioactive peptides, and short-chain fatty acids (SCFAs). These compounds strengthen the gut barrier, regulate immune responses, and influence neurotransmitters linked to stress and mood—factors that affect hair health.

Bioavailability, Absorption, and Metabolism
UALr-06 survives stomach acid and reaches the intestines alive, where it temporarily colonizes. It interacts with gut cells and microbiota, producing SCFAs and signaling molecules that circulate in the body. Effects last while supplementation continues.

Current Availability and Use
UALr-06 is widely available in probiotic capsules, powders, and multi-strain blends. It is used in clinical trials for immunity, digestion, and stress balance, making it a common addition to wellness supplements.

Clinical Features

• Gut health: Improves digestion and nutrient uptake, ensuring hair follicles receive essential vitamins and minerals.
• Stress regulation: Probiotic use lowered cortisol by ~20% in studies, which can reduce stress-related shedding.
• Immune balance: Decreases inflammatory cytokines (IL-6, TNF-α) within 4–8 weeks.
• Skin and scalp benefits: Linked to better hydration and reduced irritation, supporting healthy follicles.
• Hair growth link: Animal studies showed thicker hair and denser follicles after probiotic use.

Dosing
Typical daily dose: 1–10 billion CFU (colony-forming units). Best taken with food to improve survival through the digestive system.

Safety
Generally safe for adults and children. Some may experience mild gas or bloating when starting. Safe during pregnancy and breastfeeding. Caution is advised for severely immunocompromised individuals.

Mechanism of Action

• Gut–hair axis: Enhances absorption of biotin, zinc, and iron for hair growth.
• Immune modulation: Boosts regulatory T cells and lowers inflammation.
• Stress reduction: Influences the gut–brain axis to reduce cortisol.
• SCFA production: Generates butyrate and acetate with anti-inflammatory benefits.
• Microbiome balance: Restores healthy gut flora by competing with harmful bacteria.