SupplementsHair, skin & nailsNail strength
Silicon is the third most abundant trace element in the human body, and it concentrates exactly where you would want it for this topic: connective tissue, the hair shaft and the nail plate. The whole question with silica supplements is bioavailability — most of the silicon in a cheap tablet passes straight through you. Get the form right and there is a real, if modest, signal.
Key takeaways
- The body form that matters is orthosilicic acid; the studied supplement is choline-stabilised orthosilicic acid (ch-OSA), which keeps it soluble and absorbable.
- In women with fine hair, ch-OSA improved hair tensile strength and thickness over 9 months (Wickett 2007); an earlier trial found less nail brittleness and better hair (Barel 2005).12
- Horsetail and bamboo are naturally silica-rich but have almost no direct hair-trial evidence — and raw horsetail carries a thiaminase (vitamin B1-destroying) caveat.
- Effect is real but small; give it 5–9 months, since you are waiting for new growth.
The forms — and why they are not equal
This is where most silica products fall down. Colloidal silica and silicon dioxide are poorly absorbed. Horsetail (Equisetum) and bamboo extract are genuinely high in silica (bamboo can be ~70% silica), but that silica is largely bound and its absorption in humans is not well characterised, and no decent hair trial has been run on either. Choline-stabilised orthosilicic acid (ch-OSA) is the outlier: it delivers silicon as the absorbable orthosilicic-acid form, and it is the version used in the actual clinical trials. If you are going to bother, this is the one to look for on the label.
What the trials found
Two randomised, placebo-controlled trials carry the case. Barel and colleagues (2005) gave women with photo-damaged skin ch-OSA for 20 weeks and recorded improvements in skin, plus reduced nail brittleness and better hair.1 Wickett and colleagues (2007) ran ch-OSA for 9 months in women with fine hair and measured a genuine increase in hair tensile strength (elasticity and break load) and shaft thickness versus placebo.2 Both are on the small side and the ingredient has a commercial backer, so read them as “modest but real” rather than transformational.
Dose & patience
Trials used ch-OSA supplying roughly 10 mg of elemental silicon per day. Because you are waiting on the growth cycle, judge it at five to nine months, not five weeks. Silicon is also supplied by the diet — whole grains, oats, bananas, green beans and some mineral waters are decent sources.
Horsetail, bamboo and the caveats
If you prefer a botanical, choose a horsetail product that is explicitly thiaminase-free (heat- or ethanol-treated) — raw horsetail contains an enzyme that breaks down vitamin B1, a real concern with long-term use, and it has diuretic activity. Bamboo silica is popular in combination formulas but rests on its silica content rather than any hair trial. None of these carry the evidence ch-OSA does.
References
Adult research summary for education, not a prescription. These are food supplements, not treatments for disease.
- Barel A, Calomme M, Timchenko A, et al. Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin. Arch Dermatol Res 2005;297(4):147–53. pubmed.ncbi.nlm.nih.gov
- Wickett RR, Kossmann E, Barel A, et al. 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. pubmed.ncbi.nlm.nih.gov
This article summarises nutrition science for education. It is not a substitute for individual medical advice; consult a professional before starting a supplement, in pregnancy, or alongside medication.