Biotin is the nutrient most people name when they think of a hair vitamin. There is a good reason for that. Hair needs biotin, and when the body runs low, hair is one of the places where it shows.
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From Anirva, the maker of Hair Radiance. This article is general information, not medical advice. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
- Hair needs biotin. Thinning hair is one of the signs of low biotin, along with brittle nails and a scaly rash [1].
- Regulators accept the link. In Europe, labels may say that biotin contributes to the maintenance of normal hair [2][3].
- Low biotin is common in women with hair shedding. In one study of 541 women, 38% had a low level of biotin in the blood [5][6].
- When biotin was given, hair and nails improved. In 18 published case reports, each person had an underlying cause, and every one of them improved [4].
- Hair Radiance contains 3,000 mcg of biotin, as D-biotin. That is in line with the 2,500 mcg a day used in three studies of nails [1][9].
Here we explain what biotin does for hair, what the studies found, and who tends to run low. We also cover the amount in Hair Radiance, food sources and safety.
Facts at a glance
| Fact | Detail |
|---|---|
| Ingredient and form | Biotin (vitamin B7), as D-biotin [9] |
| Amount in Hair Radiance | 3,000 mcg (3 mg) a day, in 3 capsules [9] |
| Percent of Daily Value | 10,000% [9] |
| Adequate Intake for adults | 30 mcg a day [1] |
| Amounts used in studies | 2,500 mcg (2.5 mg) a day, in three studies of nails [1] |
| Kinds of evidence | Case reports; small human studies of nails; one study of blood levels; a regulator review [1][2][4][6] |
| Human studies cited here | 3 nail studies, 18 case reports and 1 study of blood levels in 541 women |
| Adult upper limit | None has been set [1] |
| Last reviewed | October 13, 2026 |
What is biotin?
Biotin is a B vitamin. It is also called vitamin B7 [5]. It is found in many foods and is sold as a supplement [1].
The body uses biotin as a helper for five enzymes. These enzymes handle key steps in how the body uses fats, sugars and amino acids, the building blocks of protein [1].
Adults need about 30 mcg of biotin a day. This figure is called the Adequate Intake. The Daily Value printed on US labels is also 30 mcg [1].
How does biotin support hair?
The clearest sign comes from what happens when the body runs low. The signs of low biotin include thinning hair, which can progress to loss of hair across the body. They also include a scaly red rash and brittle nails [1].
This is the plainest evidence there is. When a nutrient is missing and hair thins, hair depends on that nutrient. In 2010, the European Food Safety Authority reviewed health claims for biotin, including the claim about normal hair [2]. European law now allows labels to say that biotin contributes to the maintenance of normal hair [3].
Researchers point to the enzymes that need biotin. These enzymes help the body make fatty acids and process amino acids. One hair researcher describes this role as important for healthy skin and hair [6].
Does biotin help hair growth? What the research shows
The research on biotin and hair is still growing. Three findings matter most.
More than one in three women with hair shedding had low biotin (2016)
A study published in 2016 measured biotin in the blood of 541 women who complained of hair shedding. A low level, under 100 ng/L, was found in 38% of them [5][6].
That is a striking number. More than one in three of these women were short of a nutrient that hair needs. The study measured blood levels. It did not give the women biotin.
In every reported case, hair or nails improved (2017)
In 2017, a review searched the medical literature for reports of biotin use for hair and nails. It found 18 reported cases [4].
In every case, the person had an underlying cause of poor hair or nail growth. Every case showed improvement after biotin. The authors wrote that biotin may be of benefit for people with low biotin and for people with brittle nails [4].
Nails grew firmer in three studies
Biotin has also been studied for nails. The National Institutes of Health describes three small studies of biotin for brittle nails. Each used 2.5 mg a day, which is 2,500 mcg [1].
Study summary
| Source | Type of evidence | People | Main finding |
|---|---|---|---|
| 2016 study [5][6] | Blood test; no biotin given | 541 women with hair shedding | 38% had a low biotin level |
| 2017 review [4] | Case reports | 18 people with an underlying cause | Hair or nails improved in all 18 |
| Nail study 1 [1] | By mouth, 2.5 mg a day, 6–15 months | 22 women with brittle nails, 10 controls | Nails 25% thicker in 8 women measured twice |
| Nail study 2 [1] | By mouth, 2.5 mg a day, 5.5 months on average | 45 people with brittle nails | Firmer, harder nails in 41 (91%) |
| Nail study 3 [1] | By mouth, 2.5 mg a day, 6–15 months | 35 people with brittle nails | Improvement in 22 (63%) |
How much biotin is in Hair Radiance compared with the studies?
| Source | Amount a day | Notes |
|---|---|---|
| Hair Radiance (3 capsules) | 3,000 mcg (3 mg), as D-biotin | 10,000% of the Daily Value, from the label [9] |
| Three nail studies | 2,500 mcg (2.5 mg) | For about 5 to 15 months [1] |
| Adequate Intake for adults | 30 mcg | Set by US nutrition experts [1] |
| Usual intake from food | About 35 to 70 mcg | In western populations [1] |
Hair Radiance provides 3,000 mcg of biotin a day. This is a little more than the 2,500 mcg used in the nail studies, and it is 100 times the Adequate Intake. Those studies tested biotin by itself, so their results do not describe Hair Radiance as a whole.
The body absorbs biotin well when it is taken by mouth. Absorption of free biotin is 100%, even at amounts up to 20 mg a day [1].
22 ingredients, including 3,000 mcg of biotin
Hair Radiance is a daily three-capsule supplement that pairs biotin with vitamins, minerals, plant extracts and probiotic strains. Every ingredient and amount is listed on the label.
See Hair RadianceWhich foods contain biotin?
Many foods contain some biotin. Organ meats, eggs, fish, meat, seeds and nuts have the most [1]. Here are some examples:
- Beef liver, 3 ounces, cooked: 30.8 mcg [1]
- One whole cooked egg: 10 mcg [1]
- Canned pink salmon, 3 ounces: 5 mcg [1]
- Roasted sunflower seeds, a quarter cup: 2.6 mcg [1]
- Almonds, a quarter cup: 1.5 mcg [1]
Raw egg white contains a protein that binds biotin, so the body cannot absorb it. Cooking changes this protein. For this reason, cooked eggs are a good source of biotin [1].
Who is more likely to be low in biotin?
Severe biotin deficiency is rare in healthy people who eat a mixed diet [1]. A mild shortage is another matter. The National Institutes of Health names several groups in which it is more likely:
- Pregnant and breastfeeding women. At least a third of pregnant women develop a mild shortage of biotin [1].
- People with long-term heavy alcohol use. Blood levels of biotin are low in about 15% of this group [1].
- People who have taken certain seizure medicines for a year or more [1].
- People born with a rare condition in which the body cannot release biotin from food [1].
If you are in one of these groups and your hair has changed, biotin deserves your attention.
Is biotin safe? Safety and interactions
No upper limit has been set for biotin. The reason is that there is no evidence in people that biotin is toxic at high intakes [1]. Studies have found no adverse effects at 10 mg to 50 mg a day [1]. Mayo Clinic says that side effects have not been reported at amounts up to 10 mg a day [7]. Hair Radiance has 3 mg [9].
Biotin can change the results of some lab tests. These include tests for thyroid hormones and vitamin D [1]. They also include some tests for troponin, a marker that doctors use to check for heart damage [8]. The reports reviewed by the National Institutes of Health involved 10 mg a day or more [1]. The FDA advises doctors to ask patients about supplements that contain biotin [1].
Some seizure medicines are linked with lower biotin levels when they are taken for a year or more. They include carbamazepine, primidone, phenytoin and phenobarbital [1].
Biotin is one part of Hair Radiance
Hair Radiance is a daily three-capsule hair growth supplement with 22 ingredients: vitamins, minerals, plant extracts, an amino acid and three probiotic strains. They were chosen to support healthy hair growth, to help promote silky, smooth hair, and to strengthen and maintain healthy hair. Biotin is one of them.
Hair Radiance has not been clinically tested as a finished product. For this reason, we cannot say how its ingredients work together. The studies in this article tested biotin by itself.
If you take Hair Radiance, you are not relying on biotin alone. It is one of 22 ingredients in each serving. Every ingredient and amount is listed on the label [9].
If you are deciding
Here is the case in brief. Biotin deficiency can cause thinning hair, but thinning hair alone does not establish a deficiency [1][3]. In one study, more than one in three women with hair shedding had low biotin [5][6]. At least a third of pregnant women run low too [1]. No upper intake limit has been established, but biotin can interfere with some laboratory tests [1]. Hair Radiance covers it with 3,000 mcg a day, in line with the amount used in the nail studies [1][9]. The directions are three capsules a day with food [9].
The short version
Biotin deficiency can cause thinning hair, but thinning hair alone does not establish a deficiency. In one study, 38% of women with hair shedding had a low level. In every one of 18 published case reports, hair or nails improved with biotin in people who had an underlying cause. Hair Radiance provides 3,000 mcg of biotin a day.
Frequently asked questions
Does biotin help hair growth?
How much biotin is used for hair?
Is 5,000 mcg of biotin a lot?
5,000 mcg is the same as 5 mg. Studies have found no adverse effects at 10 mg to 50 mg a day, and no upper limit has been set. Hair Radiance has 3,000 mcg, which is 3 mg [9].
Is biotin good for men?
Is biotin good for the skin?
How long does it take biotin to work on hair?
There is no set time. The studies of biotin and nails lasted from about 5 months to 15 months [1].
Which foods have biotin?
Beef liver, eggs, salmon, sunflower seeds and almonds all contain biotin. One cooked egg has about 10 mcg [1].
How much biotin is in Hair Radiance?
Each serving of three capsules has 3,000 mcg of biotin, as D-biotin. This is 10,000% of the Daily Value [9].
References
- National Institutes of Health, Office of Dietary Supplements. Biotin: Fact Sheet for Health Professionals. Updated January 10, 2022. https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/ (accessed October 6, 2026).
- EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on the substantiation of health claims related to biotin and maintenance of normal skin and mucous membranes, maintenance of normal hair, maintenance of normal nails and other functions. EFSA Journal. 2010;8(10):1728. doi:10.2903/j.efsa.2010.1728.
- European Commission. Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. https://eur-lex.europa.eu/eli/reg/2012/432 (accessed October 3, 2026).
- Patel DP, Swink SM, Castelo-Soccio L. A review of the use of biotin for hair loss. Skin Appendage Disord. 2017;3(3):166-169. doi:10.1159/000462981. PMID: 28879195.
- Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The role of vitamins and minerals in hair loss: a review. Dermatol Ther (Heidelb). 2019;9(1):51-70. doi:10.1007/s13555-018-0278-6. PMID: 30547302.
- Trüeb RM. Serum biotin levels in women complaining of hair loss. Int J Trichology. 2016;8(2):73. doi:10.4103/0974-7753.188040. PMID: 27601860.
- Mayo Clinic. Biotin (oral route). Last updated February 1, 2026. https://www.mayoclinic.org/drugs-supplements/biotin-oral-route/description/drg-20062359 (accessed October 6, 2026).
- US Food and Drug Administration. Biotin Interference with Troponin Lab Tests: Assays Subject to Biotin Interference. Content current as of June 21, 2022. https://www.fda.gov/medical-devices/in-vitro-diagnostics/biotin-interference-troponin-lab-tests-assays-subject-biotin-interference (accessed October 6, 2026).
- Anirva. Hair Radiance Supplement Facts label and product page. https://anirva.com/pages/hair-growth-supplement-with-probiotics (accessed October 6, 2026).
