Do collagen supplements actually help hair? A London trichologist reviews the evidence
Collagen supplementation for hair sits somewhere between overhyped and worth-a-try. Here is the honest evidence.
Dr. Amara Okafor
Consultant Trichologist · Harley Street
In short
- Hair is keratin, not collagen — direct mechanism weak.
- Amino acid substrate (glycine, proline) may help via nutrition.
- 10–20g/day marine or bovine collagen; results at 3–6 months.
- Not a substitute for iron, protein or medical therapy.
Collagen has become the wellness supplement of the decade. For hair specifically, the mechanism is indirect and the evidence is thinner than the marketing. Here is what a London trichologist actually thinks.
The mechanism, honestly
Hair shafts are keratin, not collagen. But keratin synthesis requires amino acids — glycine, proline, cystine — some of which are enriched in collagen peptides. Supplementation may support the amino acid pool, particularly in people with low protein intake.
What the evidence shows
Small trials show modest improvement in hair thickness and skin hydration over 8–12 weeks with 10–15g daily hydrolysed collagen. Not comparable to minoxidil or finasteride effects. Best evidence is in post-menopausal women and those with borderline protein intake.
How to try it (if you want to)
- 10–20g/day hydrolysed collagen peptides
- Marine or bovine — no meaningful difference
- Take with vitamin C for absorption
- Give it 3–6 months
- Don't skip actual protein: 1.2g/kg/day minimum
Frequently asked
Common questions
Is one brand better?+
No. Look for third-party testing (Informed Sport) and low sugar/additive content.
Can it replace protein intake?+
No — total protein still matters. Collagen is a supplement, not a source.
Any risks?+
Very low. Marine collagen — allergy risk if seafood allergic.
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