Horsetail is a plant with a long history of use, and it is in hair formulas for one reason: silicon. Horsetail is a plant source of silicon, a mineral found in hair, skin and nails.
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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.
- Horsetail is a plant source of silicon. Silicon is the third most abundant trace element in the human body [2].
- Silicon by mouth made hair strands stronger and thicker in a trial. In 48 women with fine hair, 10 mg of silicon a day for 9 months improved both measures [2][3].
- A supplement with horsetail silica raised hair diameter. In 40 women, average hair diameter rose from 0.060 to 0.067 mm over 6 months [4].
- Horsetail extract has not been tested by itself for hair. The trials used another form of silicon, or a blend [3][4].
- Hair Radiance contains 50 mg of horsetail extract. Horsetail has been used safely by mouth for at least 30 years [1][5].
The hair research is about silicon more than about horsetail itself. In a 9-month trial, women who took silicon by mouth had stronger and thicker hair strands. In a 6-month trial, a supplement that contained horsetail silica raised hair diameter. This article explains both, and what they mean for the 50 mg in Hair Radiance.
Facts at a glance
| Fact | Detail |
|---|---|
| Ingredient and form | Horsetail (Equisetum arvense) extract, stem and leaf [5] |
| Amount in Hair Radiance | 50 mg a day, in 3 capsules [5] |
| Percent of Daily Value | No Daily Value has been set [5] |
| Amounts used in studies | 10 mg of silicon a day in the silicon trial. The blend trial does not give its horsetail amount [3][4] |
| Kinds of evidence | A regulator review; a review of silicon; one human trial of silicon; one human trial of a blend with horsetail silica [1][2][3][4] |
| Human studies cited here | 2 trials: 48 women (silicon) and 40 women (a blend). None of horsetail extract by itself |
| Adult upper limit | None has been set |
| Last reviewed | [DATE] |
What is horsetail?
Horsetail is a plant whose botanical name is Equisetum arvense. The parts used are the stems and leaves that grow above the ground [1]. In Europe, horsetail has a long record of use by mouth, usually as a tea [1].
Horsetail is used in supplements as a plant source of silicon [2]. On labels, silicon from plants is often called silica. Hair Radiance contains 50 mg of horsetail extract [5].
How might horsetail support hair?
Silicon is part of hair, skin and nails
Silicon is the third most abundant trace element in the human body [2]. A 2016 review suggests that a higher silicon content in the hair fiber goes with a lower rate of hair loss and more brightness [2]. In skin, silicon is thought to matter for making collagen [2].
The body absorbs some forms of silicon better than others
The body takes in silicon in a simple form called orthosilicic acid. How much is absorbed depends on the form, from under 1% to nearly 50% [2].
For horsetail, the data are thin. In one healthy volunteer, horsetail extract tablets raised the silicon passed in the urine, a sign that some was absorbed [2].
Does horsetail help hair growth? What the research shows
The research on horsetail and hair is still growing. Two human trials are relevant. One tested silicon in another form. One tested a blend that contained horsetail silica. No trial has tested horsetail extract by itself for hair.
In 48 women, silicon by mouth made hair strands stronger and thicker (2007)
This trial enrolled 48 women with fine hair. Half took 10 mg of silicon a day, in a form called choline-stabilized orthosilicic acid. Half took a placebo. The trial ran for 9 months [2][3].
In the silicon group, hair strands resisted breaking better, and their cross-section grew significantly. The placebo group showed no significant change [2].
In 40 women, a supplement with horsetail silica raised hair diameter (2015)
This trial enrolled 40 women with thinning hair. Half took a supplement twice a day for 180 days, and half took a placebo. The supplement combined a marine protein complex with silica from horsetail, vitamin C and other ingredients [4].
In the supplement group, average hair diameter rose from 0.060 mm to 0.067 mm, and the number of full-size hairs increased. The placebo group showed no significant change. No adverse events were reported [4].
The supplement was a blend, so the result cannot be credited to horsetail alone. Its maker paid for the trial [4].
Study summary
| Study | What was used | Result |
|---|---|---|
| Wickett et al., 2007 [3] | 10 mg of silicon a day by mouth; 48 women; 9 months | Stronger strands with a larger cross-section |
| Ablon and Dayan, 2015 [4] | A blend with horsetail silica by mouth; 40 women; 180 days | Hair diameter up from 0.060 to 0.067 mm |
| Review of silicon, 2016 [2] | Horsetail extract tablets; one volunteer | More silicon passed in the urine |
How much horsetail is in Hair Radiance compared with the studies?
| Source | Amount a day | Notes |
|---|---|---|
| Hair Radiance (3 capsules) | 50 mg of horsetail extract | From the label [5] |
| Silicon trial, 2007 | 10 mg of silicon | As choline-stabilized orthosilicic acid [2][3] |
| Blend trial, 2015 | One tablet twice a day | The horsetail amount is not given [4] |
These amounts cannot be compared directly. The silicon trial counted silicon itself, in another form. Hair Radiance lists its horsetail as 50 mg of extract, and an extract is not all silicon.
22 ingredients, including 50 mg of horsetail extract
Hair Radiance is a daily three-capsule supplement that pairs horsetail extract with vitamins, other plant extracts and probiotic strains. Every ingredient and amount is listed on the label.
See Hair RadianceIs horsetail safe? Safety and interactions
European regulators report that horsetail has been used safely by mouth for at least 30 years [1]. They support its use in adults and in adolescents over the age of 12 [1].
Horsetail has a mild effect on urine production [1]. For that reason, regulators advise against it when a doctor has recommended a reduced fluid intake, for example in severe heart or kidney disease [1].
Side effects reported with horsetail are allergic reactions and mild stomach complaints [1].
Horsetail 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. Horsetail extract 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.
Every ingredient and amount is listed on the label [5].
If you are deciding
Here is the case in brief. Horsetail is a plant source of silicon, a mineral found in hair [2]. In a 9-month trial, silicon by mouth made hair strands stronger and thicker [2][3]. In a 6-month trial, a supplement with horsetail silica raised hair diameter [4]. Horsetail extract has not been tested by itself for hair, so its place in Hair Radiance rests on this silicon research. Hair Radiance supplies 50 mg of horsetail extract a day [5]. The directions are three capsules a day with food [5].
The short version
Horsetail is a plant source of silicon, a mineral found in hair. In one trial, silicon by mouth made hair strands stronger and thicker. In another, a blend with horsetail silica raised hair diameter. Horsetail by itself has not been tested for hair. Hair Radiance provides 50 mg of horsetail extract a day.
Frequently asked questions
Does horsetail help hair growth?
Is silica good for hair?
What is the difference between silica and silicon?
Silicon is the mineral. Silica is a compound of silicon and oxygen, and labels often use this word for silicon from plants.
How long does silica take to work for hair?
Is horsetail safe?
Who should not take horsetail?
Does horsetail make you urinate more?
Horsetail has a mild effect on urine production [1].
How much horsetail is in Hair Radiance?
Each serving of three capsules has 50 mg of horsetail extract [5].
References
- European Medicines Agency. Horsetail herb: summary for the public. EMA/147173/2016. April 5, 2016. https://www.ema.europa.eu/en/medicines/herbal/equiseti-herba (accessed October 7, 2026).
- Araújo LA, Addor F, Campos PMBGM. Use of silicon for skin and hair care: an approach of chemical forms available and efficacy. An Bras Dermatol. 2016;91(3):331-335. doi:10.1590/abd1806-4841.20163986.
- Wickett RR, Kossmann E, Barel A, Demeester N, Clarys P, Vanden Berghe D, Calomme M. Effect of oral intake of choline-stabilized orthosilicic acid on hair tensile strength and morphology in women with fine hair. Arch Dermatol Res. 2007;299(10):499-505. doi:10.1007/s00403-007-0796-z. PMID: 17960402.
- Ablon G, Dayan S. A randomized, double-blind, placebo-controlled, multi-center, extension trial evaluating the efficacy of a new oral supplement in women with self-perceived thinning hair. J Clin Aesthet Dermatol. 2015;8(12):15-21.
- Anirva. Hair Radiance Supplement Facts label and product page. https://anirva.com/pages/hair-growth-supplement-with-probiotics (accessed October 7, 2026).
