Which supplements for hair loss have evidence?

This entry is part of the Nutri Tailor Health Reference Library — cited research on supplements, nutrients and adjacent areas of health.

Summary

Testing comes before buying, because hair-loss supplements only work where something is low. Iron carries the most consistent signal in diffuse shedding, with ferritin corrected under 50 in menstruating women or under 30 otherwise. Zinc and vitamin D are corrected where low, with no benefit where replete. Biotin helps only in rare biotin deficiency, and high doses distort thyroid and heart blood tests. Silicon as ch-OSA has small trials on hair strength. Protein at 1.2 g per kg matters more than any capsule. Receding or crown thinning is pattern loss, hormonal and a GP or pharmacist matter, while shedding two to three months after an illness, birth or crash diet is telogen effluvium and usually recovers.

Supplements mentioned in this articleAll supplements in the Nutri Tailor store are GMP-certified, practitioner-grade & made in the UK

Iron & Vitamin C →£26.40Iron bisglycinate, the gentler chelated form, taken once daily with a meal. The vitamin C supports same-meal absorption, and as the evidence shows, iron corrects deficiency with or without it. 90 capsules matches the three month retest interval.
Zinc Picolinate →£22.31Zinc picolinate, the well absorbed form, for the mineral behind over 200 enzymatic reactions including immune function and skin repair.
Biosilica →£29.5025 mg silicon as choline stabilised orthosilicic acid (ch-OSA), the most bioavailable silicon form, relevant to hair, skin and connective tissue.

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How it works

Hair follicles are among the fastest-dividing tissues in the body and are the first to be down-regulated when the body senses a shortfall, which is why shedding follows a stressor by two to three months. The follicle shifts to the resting phase at the time of the insult and the hair falls when the next cycle starts. Iron, zinc, protein and vitamin D all feed that division, and correcting a deficit lets the next cycle grow normally, which is why results take months. Biotin is a cofactor in keratin production, but deficiency is rare and extra biotin in a replete person does nothing except interfere with laboratory assays. Silicon supports collagen cross-linking in the hair shaft, which is a strength effect rather than a growth effect. Pattern hair loss runs on androgens at the follicle and no nutrient changes that.

Timing

Shedding lags its trigger by two to three months and recovery lags correction by three to six. Ferritin rebuilds over three to six months. Judge any intervention at six months. Biotin is stopped for at least three days before any thyroid or cardiac blood test.

Safety profile

Patchy loss, loss with scalp pain or scarring, loss with fatigue, weight change or a neck swelling, or sudden loss in a child needs a GP. Iron is not taken blind; test first. High-dose biotin distorts thyroid and troponin assays and has produced missed heart attacks; it is declared before any blood test. Zinc above 25 mg long-term depletes copper. Pattern hair loss does not respond to nutrients and delay costs follicles. Nutri365 checks for interactions and contraindications before suggesting any nutritional step and refers the scalp conditions.

Special populations

Postpartum shedding at three months is normal and recovers. Menstruating women and vegans are the iron and zinc groups. Perimenopause thins hair hormonally and is on the [perimenopause page](/apps/learn/perimenopause-symptoms-and-what-actually-helps). Men with receding temples have pattern loss and the nutrient list does not apply unless something is also low. Anyone who has crash-dieted has a protein and iron problem first.

Guideline positions

Almohanna 2019, review of vitamins and minerals in hair loss: iron deficiency associated with telogen effluvium with conflicting trial results; zinc and vitamin D deficiency associated with hair loss and correction reasonable where low; biotin supplementation beneficial only in deficiency; no evidence for supplementing replete individuals. NIH Office of Dietary Supplements on biotin: adequate intake about 30 micrograms; high-dose biotin interferes with assays including thyroid and troponin. Wickett 2007 and Barel 2005: choline-stabilised orthosilicic acid improved hair tensile strength and skin and nail measures in small trials. BSG 2021 on ferritin thresholds. The iron-hair question in full is on the [hair shedding and ferritin page](/apps/learn/hair-shedding-and-ferritin-what-the-evidence-and-tests-say).

Practical framework

The loss is classified first. Diffuse shedding two to three months after a trigger is telogen effluvium, receding temples or a widening parting is pattern loss, and patches are alopecia areata, which needs a GP. The tests come next, meaning ferritin, full blood count, zinc, vitamin D and TSH, with protein intake and any crash diet noted. What is low is corrected. Iron bisglycinate runs with vitamin C where ferritin is under 50 in a menstruating woman or under 30 otherwise, read on the [ferritin hub](/apps/learn/ferritin-blood-test-results-explained-uk-what-your-number-means). Zinc picolinate runs at 15 to 25 mg for three months where low. Vitamin D3 brings the level above 50 nmol/L, on the [vitamin D hub](/apps/learn/vitamin-d-blood-test-results-explained-uk-what-your-number-means). Protein reaches 1.2 g per kg. Where everything is normal and the loss is diffuse, silicon as ch-OSA is the one supplement with a strength effect worth a six-month trial, per the [silica page](/apps/learn/is-silica-worth-taking-for-hair-skin-nails-which-form-works), and biotin is not, per the [biotin page](/apps/learn/biotin-vitamin-b7-high-dose-and-the-blood-test-warning). Pattern loss goes to the pharmacist or GP, where minoxidil and other options exist. The judgement comes at six months, because that is one hair cycle. Nutri365 reads whether the shedding tracks the ferritin, the protein or the stress across those months, checks for interactions and contraindications, and refers questions outside scope to a health specialist.

Common misconceptions

Biotin does not grow hair in people who are not deficient. Hair gummies are mostly biotin. Collagen supplements have no hair-growth trials. Shedding a few months after a stressful period is not a deficiency, because it is the hair cycle, and it recovers.

Sources

Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A 2019. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatology and Therapy. PMID: 30547302
2025. Biotin Fact Sheet for Health Professionals. NIH Office of Dietary Supplements.
Wickett RR, Kossmann E, Barel A, et al 2007. Effect of oral intake of choline-stabilized orthosilicic acid on hair tensile strength and morphology in women with fine hair. Archives of Dermatological Research. PMID: 17960402
Barel A, Calomme M, Timchenko A, et al 2005. Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin. Archives of Dermatological Research. PMID: 16205932
Snook J, Bhala N, Beales ILP, et al 2021. British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults. Gut. PMID: 34497146