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Best peptides for hair growth: what the evidence in people shows.

Peptide Chooser editorial team. Checked 2 Nov 2026.

Short answer

No peptide has been shown to grow hair in large trials in people. Finasteride and minoxidil, which are not peptides, are the FDA-approved options.12 Copper peptides have a lab study on hair follicles behind them, PTD-DBM has mouse and cell studies, and biotin has helped only people with a condition behind their hair loss.345 Injectable research-use peptides have no hair evidence in people that we could find.

Which peptides are sold for hair?

Four kinds of product come up when you search for hair peptides.

  • Copper peptides (GHK-Cu) in serums and shampoos, sold as cosmetics.7
  • PTD-DBM, a lab-made peptide that some scalp serums now list.
  • Biotin, often sold next to peptides. It is vitamin B7, not a peptide.8
  • Injectable peptides. Research-use shops sell vials of BPC-157, GHK-Cu and TB-500 that are meant to be injected. 78 shops we track list BPC-157; the middle price across their listings is $5.95 per mg.6 76 shops we track list GHK-Cu; the middle price across their listings is $0.65 per mg.6 75 shops we track list TB-500; the middle price across their listings is $6.65 per mg.6

The question for each one is the same: was it tested on hair in people, and what did the test measure?

What do copper peptides have behind them?

The study that hair pages quote, ours included, is from 2007. Researchers kept human hair follicles alive in a dish and added a copper peptide; the follicles grew longer.3 The peptide in that study was AHK-Cu, a close relative of GHK-Cu, not GHK-Cu itself.3

A 2026 review of the GHK-Cu research found four decades of lab and animal work, but called the studies in people thin: most trials were small and tested face creams.9 We found no large trial of GHK-Cu for hair loss in people. Our GHK-Cu guide goes through it in more detail.

What is PTD-DBM?

PTD-DBM is a peptide built in a lab to block a protein called CXXC5, which slows a signal that hair follicles need to grow. In a 2017 study, mice treated with it regrew hair faster, and cells from human balding scalps showed more of the CXXC5 protein.4

That is a study in mice and in cells. We found no published trial in people that shows PTD-DBM grows hair.

Does biotin help hair grow?

Only in people who lack it. A lack of biotin can cause hair loss, skin rashes and brittle nails.8 A 2017 review found 18 reported cases where biotin helped hair or nails, and every one of those people had an underlying condition. The authors found no good evidence for biotin in healthy people.5

What about injectable peptides?

None of the vials sold for hair is FDA approved for any use, and we found no study in people that shows any of them grows hair. Our guide on injectable peptides for hair growth has the FDA status of each one.

Why do finasteride and minoxidil come first?

Because they were tested on hair in people, in large trials. In two one-year trials with 1,553 men, those who took finasteride had 107 more hairs than the placebo group after one year, and 138 more after two years. The men on placebo kept losing hair.10

Minoxidil, put on the scalp, helps hair grow and slows balding, most in people under 40 whose hair loss is recent.2 Both work only while you use them.12

What does "and thickness" mean in hair studies?

Product pages say "thicker hair". Trials measure something you can check. The finasteride trials counted the hairs in a marked circle of scalp one inch across, compared photos judged by a panel of experts and asked the men and the doctors to rate the change.10

So when a product promises thicker hair, ask three things:

  • Was it tested in people, in animals or in a dish?
  • What was measured: a hair count, photos or only how people felt?
  • How many people took part, and was there a group that got a dummy product?

A cosmetic does not have to answer any of these before it is sold.7 None of this is medical advice. A doctor or dermatologist can tell you which option fits your hair loss.

What to do next

Compare hair optionsPeptides for hair loss guide

Sources

  1. MedlinePlus, Finasteride, revised 15 Jun 2026: https://medlineplus.gov/druginfo/meds/a698016.html
  2. MedlinePlus, Minoxidil Topical: https://medlineplus.gov/druginfo/meds/a689003.html
  3. Pyo HK et al., The effect of tripeptide-copper complex on human hair growth in vitro, Arch Pharm Res 30(7), 2007, PubMed 17703734: https://pubmed.ncbi.nlm.nih.gov/17703734/
  4. Lee SH et al., Targeting of CXXC5 by a competing peptide stimulates hair regrowth and wound-induced hair neogenesis, J Invest Dermatol 137(11), 2017, PubMed 28595998: https://pubmed.ncbi.nlm.nih.gov/28595998/
  5. Patel DP et al., A review of the use of biotin for hair loss, Skin Appendage Disord 3(3), 2017, PubMed 28879195: https://pubmed.ncbi.nlm.nih.gov/28879195/
  6. Peptide Chooser database: the research-use and cosmetic peptide shops we check, 2 Nov 2026. Their prices and checks are in the seller windows on our goal pages
  7. FDA, FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated: https://www.fda.gov/cosmetics/laws-regulations/fda-authority-over-cosmetics-how-cosmetics-are-not-fda-approved-are-fda-regulated
  8. MedlinePlus Medical Encyclopedia, Pantothenic acid and biotin, reviewed 21 Jan 2025: https://medlineplus.gov/ency/article/002410.htm
  9. Najafi N et al., A systematic review of the mechanisms and therapeutic applications of GHK-Cu in topical microneedle delivery, Arch Intern Med Res 9(3), 2026, PubMed 42787770: https://pubmed.ncbi.nlm.nih.gov/42787770/
  10. Kaufman KD et al., Finasteride in the treatment of men with androgenetic alopecia, J Am Acad Dermatol 39(4), 1998, PubMed 9777765: https://pubmed.ncbi.nlm.nih.gov/9777765/