Collagen for Hair and Nails: What Has Been Measured

Collagen has been measured for nails in one open-label study, and for hair as one outcome among several in two placebo-controlled trials. In an open-label study of 25 people, 2.5 g of collagen peptides a day for 24 weeks increased the nail growth rate by 12% and cut the frequency of broken nails by 42%; there was no placebo group. No randomised trial has tested collagen on its own with hair growth or shedding as its main outcome.¹ Shedding has common causes a GP can check.⁷ This page sits beneath the Wellgard collagen guide.

Sources checked on 29 October 2026.

Does collagen help nails?

One study has measured it directly. In 2017, 25 people with brittle nails took 2.5 g of bovine collagen peptides once a day for 24 weeks, then stopped for four weeks. Growth rate rose by 12% and the frequency of broken nails fell by 42%; 64% were judged improved overall, 88% were still improved four weeks after stopping.¹

It was open-label and single-centre, with no placebo group, and the peptides came from a manufacturer. Collagen itself carries no authorised health claim in Great Britain, a statement about the register rather than a verdict on the study; the authorised nail wording, for a product that qualifies, is "Zinc contributes to the maintenance of normal nails".¹²

In a second trial, 85 healthy women aged 43 to 65 were randomised to 5 g of collagen peptides or placebo for 84 days, with skin as the main question; nail colour improved in the collagen group within 28 days and in the placebo group only at 84 days.² Colour is not strength or growth: a controlled signal that nails respond, not the missing growth trial.

How long before nails change?

The study measured at 24 weeks, so its figures are six-month figures.¹ What you can notice after taking collagen puts nails alongside the other timelines.

Does collagen help hair growth?

Hair is keratin: the strand is a dead keratin fibre, and swallowed collagen does not become it. Follicles, which make the strand, sit in the dermis, which is largely collagen, and their stem cells depend on a collagen of their own, type XVII. A 2016 study in mice and human scalp samples found that as follicles age, their stem cells break down type XVII collagen, the follicle shrinks and hair thins; keeping that collagen in place in mice held the process back.³

Three human trials come close. In a 2026 randomised, placebo-controlled trial run by its maker, 114 women aged 20 to 50 with thigh cellulite and self-reported hair thinning took 1,000 mg a day of low-molecular-weight fish collagen peptides or placebo for 24 weeks. The trial measured cellulite severity, skin roughness and elasticity alongside hair shaft diameter, which increased significantly at week 24 in the collagen group.⁴ A 2025 placebo-controlled trial in 80 menopausal women found 5 g a day of fish collagen alone slowed hair shedding against placebo over six months, as did calcium with vitamin D, one outcome among several.⁵

The third, run by its maker, is not collagen evidence on its own. In 2023, 83 people with pattern hair loss or chronic telogen effluvium, all on a hair-loss medicine chosen by their clinician, were randomised to add a daily tablet of 300 mg fish collagen with taurine, cysteine, methionine, iron and selenium, or not. After 12 weeks a blinded assessor's photographic score was 1.67 with the tablet against 0.66 without.⁶

Why is my hair falling out?

The NHS hair-loss page: "It's normal to lose hair. We can lose between 50 and 100 hairs a day, often without noticing." Hair loss "is not usually anything to be worried about, but occasionally it can be a sign of a medical condition." Some types are permanent, "like male and female pattern baldness", which "usually runs in the family". Others "may be temporary" and "can be caused by: an illness, stress, cancer treatment, weight loss, iron deficiency." The advice: see a GP "if you're worried about your hair loss". On recovery: "Hair loss caused by a medical condition usually stops or grows back once you've recovered."⁷

The temporary pattern has a name and a delay. Telogen effluvium is the commonest cause of diffuse shedding, and it appears three to four months after the trigger.⁸ Hair loss on Mounjaro covers the fast-weight-loss version.

Two checkable causes sit on NHS symptom lists. Iron deficiency anaemia lists "hair loss, you notice more hair coming out when brushing or washing it" among its less common symptoms, and is "often because of blood loss or pregnancy".⁹ An underactive thyroid lists "dry skin, dry hair or hair loss"; an overactive one lists "patchy hair loss or thinning".^{10, 11} Patchy loss, scarring, soreness or shedding that does not settle are reasons to see a GP, who can order the blood tests and check your medicines.

Shedding after having a baby follows the same telogen pattern, and the NHS rule for temporary hair loss applies: it grows back, with a GP if you are worried.^{7, 8} Collagen in pregnancy and breastfeeding covers that time.

Biotin or collagen for thinning hair?

Collagen is a protein with two controlled hair measurements, diameter and shedding, each one endpoint among several, and no trial of its own for hair.^{4, 5} Biotin is a B vitamin with an authorised wording: "Biotin contributes to the maintenance of normal hair", for a food that supplies enough to qualify.¹² That describes biotin's role in normal hair, not growth. Is biotin good for hair growth has the evidence and the blood-test rule. The NHS says biotin is needed "in very small amounts", that a varied and balanced diet should supply it, and that "taking 0.9mg or less a day of biotin in supplements is unlikely to cause any harm."¹³

Zinc and copper carry the other wordings: "Zinc contributes to the maintenance of normal hair" and "to the maintenance of normal nails"; "Copper contributes to normal hair pigmentation".¹² The NHS puts daily needs at about 9.5 mg of zinc for men, 7 mg for women and 1.2 mg of copper, and says not to exceed 25 mg of zinc a day unless a doctor advises it, because high zinc intakes reduce copper absorption.¹⁴ A product that also contains biotin or zinc at a qualifying level may carry that nutrient's wording. What to take with collagen goes through the co-nutrients; does zinc help with hair loss covers the zinc trials.

Which collagen is best for hair and nails?

No trial has compared collagen sources on a hair or nail result. The nail study used bovine peptides at 2.5 g; the hair measurements came from fish peptides at 1 g and 5 g; the combination tablet used 300 mg of fish collagen.^{1, 4, 5, 6} No source has been shown to outperform another, so "best for hair" has no evidence behind it as a type. Men will find the muscle, tendon and hair evidence in collagen for men.

What we don't know

Whether collagen peptides taken alone change hair growth or shedding: no trial has asked that first, though both controlled measurements went in collagen's favour.^{4, 5} Whether eating collagen changes the type XVII collagen the follicle makes for itself: no study has tested it.³ Whether nails grow or break differently against a placebo: the one growth study had none, and the controlled trial measured colour.^{1, 2} Each is a gap in the evidence, not a finding that collagen does not work.

Frequently asked questions

Will taking collagen make my nails stronger?

The measured result: in 25 people taking 2.5 g a day for 24 weeks, broken nails fell by 42% and growth rate rose by 12%, with no placebo group.¹

Is a salon collagen hair treatment the same as a collagen supplement?

No. A salon "collagen treatment" is a smoothing or conditioning product painted onto the hair and usually sealed with heat: a protein coating on the dead keratin strand that wears off with washing. Swallowed collagen peptides are digested and absorbed as protein; they do not coat the strand.

Does silica help hair or nails?

Silicon has no authorised hair or nail claim in Great Britain.¹⁵ In 48 women with fine hair, 10 mg of silicon a day for nine months limited the fall in hair-fibre break load (2.2% against 10.8% on placebo) and thickened the fibre; growth and shedding were not measured.¹⁶ In 50 women with photodamaged skin, 20 weeks at the same dose cut self-rated nail and hair brittleness against baseline, not against placebo.¹⁷ No trial has tested any form of silicon for hair loss. What is silica good for has the rest.

Biotin or silica for thinning hair?

Neither has a hair-growth trial in people with normal levels; biotin's wording is biotin's alone, and silicon's one hair trial measured fibre strength, not growth.^{12, 15, 16}

Sources

1. Hexsel D, et al. Journal of Cosmetic Dermatology, 2017. Open-label study, 25 people, 2.5 g for 24 weeks; supplier-linked authors. PubMed 28786550.
2. Vleminckx S, et al. Journal of Cosmetic Dermatology, 2024. Randomised trial, 85 women aged 43 to 65, 5 g for 84 days; run by the peptide manufacturer's own scientists. PubMed 39143887.
3. Matsumura H, et al. Hair follicle aging is driven by transepidermal elimination of stem cells via COL17A1 proteolysis. Science, 2016. Laboratory study, mice and human scalp samples; funding not stated on PubMed. PubMed 26912707.
4. Hwang S, et al. Journal of Medicinal Food, 2026. Randomised trial, 114 women aged 20 to 50, 1 g for 24 weeks; authors employed by the maker. PubMed 41788055.
5. Duangjai A, et al. Clinics and Practice, 2025. Randomised trial, 80 menopausal women in four groups, 6 months; publicly funded, no conflicts declared. PubMed 41002783.
6. Milani M, Colombo F. Skin Research and Technology, 2023. Randomised, assessor-blinded trial, 83 people, 12 weeks; authors employed by the supplement's maker. PubMed 37357646.
7. NHS. Hair loss. Page last reviewed 24 January 2024. nhs.uk.
8. Malkud S. Telogen effluvium: a review. Journal of Clinical and Diagnostic Research, 2015. Narrative review; funding not stated on PubMed. PubMed 26500992.
9. NHS. Iron deficiency anaemia. Page last reviewed 26 January 2024. nhs.uk.
10. NHS. Underactive thyroid: symptoms. Page last reviewed 28 April 2025. nhs.uk.
11. NHS. Overactive thyroid: symptoms. Page last reviewed 11 April 2023 (review overdue). nhs.uk.
12. Regulation (EU) No 432/2012 (assimilated GB law), Annex: permitted health claims (checked 29 October 2026). legislation.gov.uk.
13. NHS. B vitamins and folic acid (biotin). Page last reviewed 3 August 2020 (review overdue). nhs.uk.
14. NHS. Others: vitamins and minerals (zinc, copper). Page last reviewed 3 August 2020 (review overdue). nhs.uk.
15. Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register. Page last updated 19 May 2026. gov.uk.
16. Wickett RR, et al. Archives of Dermatological Research, 2007. Randomised trial, 48 women with fine hair, 10 mg silicon for 9 months; supplier-linked authors. PubMed 17960402.
17. Barel A, et al. Archives of Dermatological Research, 2005. Randomised trial, 50 women, 10 mg silicon for 20 weeks; supplier-linked authors. PubMed 16205932.

Spotted something out of date? Email support@wellgard.co.uk with the page address and the sentence.