Encyclopedia · protein or peptide
Collagen peptides
A protein powder with modest skin evidence and very little for hair.
What it is
Collagen peptides are broken-down collagen protein from cows or fish, sold as powders, drinks and capsules mainly for skin and joints.
How it works
Once swallowed they are digested into amino acids like any protein. In cell and mouse work, a fish collagen peptide acted on signalling pathways in dermal papilla cells, which sit at the base of the hair follicle. Whether this happens in people is unknown.
What the studies show
- In human dermal papilla cells and mice, a tilapia collagen peptide increased cell growth and regrowth, raising Wnt/beta-catenin and lowering BMP signalling. This is animal and cell evidence only. Hwang 2022
- A 12-week placebo-controlled trial of hydrolysed collagen plus vitamin C improved skin hydration and elasticity. Trichoscopy hair count was 27.6% higher than placebo but not statistically significant, while a grading of healthy hair appearance was 31.9% higher (p<0.01). The study was run by the product company. Reilly 2024
- In 83 people, a tablet with marine collagen, amino acids, iron and selenium added to drug treatment gave a better global assessment than drugs alone. The share due to collagen cannot be separated. Milani 2023
- A review found social-media and company claims about oral collagen outrun the evidence. Rustad 2022
Side effects and safety
Generally well tolerated. Marine collagen is unsuitable with fish allergy, and bovine collagen if you avoid beef. Monthly cost is moderate to high for the amounts used in studies.
Bottom line
If you take collagen for skin, any hair effect is a bonus, not a reason to buy it. Eating enough protein matters more; see diet and hair. Discuss with a doctor.
Studies 4
Hwang SB et al. Hair-Growth-Promoting Effects of the Fish Collagen Peptide in Human Dermal Papilla Cells and C57BL/6 Mice Modulating Wnt/β-Catenin and BMP Signaling Pathways. 2022
Tested: tilapia collagen peptide
Result: Increased cell proliferation and regrowth in mice, with Wnt/beta-catenin up and BMP down.
Read the study ↗Reilly DM et al. A Clinical Trial Shows Improvement in Skin Collagen, Hydration, Elasticity, Wrinkles, Scalp, and Hair Condition following 12-Week Oral Intake of a Supplement Containing Hydrolysed Collagen. 2024
Tested: hydrolysed collagen plus vitamin C vs placebo
Result: Skin hydration and elasticity improved; trichoscopy hair count up 27.6% but not significant; healthy-appearance grading up 31.9% (p<0.01); product-company study.
Read the study ↗Milani M et al. Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study. 2023
Tested: tablet with marine collagen, amino acids, iron and selenium added to drugs vs drugs alone
Result: Global assessment 1.67 vs 0.66; assessor-blinded; contribution of individual ingredients cannot be separated.
Read the study ↗Rustad AM et al. Myths and media in oral collagen supplementation for the skin, nails, and hair: A review. 2022
Result: Social-media and company claims about oral collagen outstrip the evidence.
Read the study ↗Related
- Marine protein supplements (Viviscal, Nourkrin)Branded fish- and shellfish-extract pills with positive but small, manufacturer-linked trials.
- Oral keratin supplementsKeratin capsules with one small company-linked trial and no sign that swallowed keratin reaches your hair.
- L-cysteineAn amino acid that makes up much of hair keratin, with no controlled hair trial on its own.
- Hair supplement blends (Nutrafol, Viviscal and similar)Branded multi-ingredient hair vitamins that beat placebo in small, mostly company-linked trials.
- Diet and hairCrash diets and rapid weight loss cause shedding, ordinary diets rarely do, and testing beats guessing before you buy supplements.