Best Peptides for Hair Growth, Ranked by Human Evidence

Peptides for hair growth ranked by human trials: oral collagen and GHK lead with one small trial each. What was measured, legal status, and what has no data.

Written bySebastian Hunter, Founder and EditorI'm a 42-year-old senior advisor and distance runner who came to peptides as a sceptic. I'm not a doctor: I read the research, run my own experiment and keep honest notes. Read full bio

Published October 3, 2026

The short version

Two peptides have a placebo-controlled human trial that measured hair. Oral collagen peptides gave thicker hair shafts in 114 women. GHK, the peptide in GHK-Cu, combined with another ingredient gave more hairs at one strength in 45 men. Each rests on one small trial. TB-500's parent protein, thymosin beta-4, has only rat and mouse data on its own. I found no hair study of BPC-157 or the growth-hormone peptides. The approved hair-loss drugs, minoxidil and finasteride, are not peptides.

Oral collagen peptides have the largest placebo-controlled peptide hair trial: 114 women, 24 weeks, thicker hair shafts.
I found no trial of GHK-Cu alone on hair. The one trial paired copper-free GHK with 5-aminolevulinic acid.
Thymosin beta-4, the protein TB-500 comes from, grew hair in rats and mice. I found no human hair study of either on its own.
I found no hair study of BPC-157, CJC-1295, ipamorelin or MK-677.
FDA treats a claim to "restore hair growth" as a drug claim, so a cosmetic serum cannot legally promise regrowth.

Oral collagen peptides have the most human evidence for hair growth, and it is one trial. In it, 114 women took a collagen supplement or placebo for 24 weeks, and their hair shafts grew thicker on collagen Hwang 2026 - Hwang S, Won J, Kim S et al. Low-Molecular-Weight Collagen Peptide Supplementation Improves Cellulite Severity, Skin Elasticity, and Hair Shaft Diameter: A Clinical Study with Pharmacokinetic Evaluation. J Med Food. 2026;29(4):187-195., in the references below. GHK, the peptide in GHK-Cu, comes next with one 45-person trial in a combination. I found no human hair study of the injected research peptides sold for hair.

The ranking below orders compounds by how much human hair data they have and how good it is. A higher rank means better evidence, not that a compound will regrow your hair. None of them is approved to treat hair loss. The approved hair-loss drugs, minoxidil and finasteride, are not peptides Fan 2026 - Fan C, Chen Y, Huang Q et al. Overview of Short Peptides for Hair Loss. Biomedicines. 2026;14(4)., in the references below. For skin, see peptides for skin.

Peptides for hair growth compared

Rank	Compound	Human evidence on hair	What was measured	US legal status	Our page
1	Collagen peptides (oral)	1 placebo-controlled trial (114 women, 24 weeks); 1 trial of a multi-ingredient supplement	Hair shaft diameter; photo scores	Dietary supplement	Collagen for hair
2	GHK / GHK-Cu (topical)	1 placebo-controlled trial of copper-free GHK with 5-ALA (45 men, 6 months); uncontrolled mixtures	Hair count up at one strength; thickness and length unchanged	Cosmetic ingredient	GHK-Cu
3	Acetyl tetrapeptide-3 (hair serums)	1 trial of a 3-ingredient blend against minoxidil (32 people)	Terminal hair count	Cosmetic ingredient	None yet
4	TB-500 (thymosin beta-4)	None on its own; rat and mouse studies; 1 uncontrolled mixture	Hair growth in rodents	Research chemical	TB-500
5	BPC-157	None found, in people or animals	Nothing on hair	Research chemical	BPC-157
6	CJC-1295, ipamorelin, MK-677	None found	Nothing on hair	Research chemicals	MK-677 and hair loss

1. Collagen peptides: one trial measured hair thickness

The main collagen trial enrolled 114 women aged 20 to 50 with cellulite and self-reported hair thinning. They took 1,000 mg a day of a low-molecular-weight fish collagen peptide or placebo for 24 weeks. By week 24, hair diameter had increased significantly on collagen, and more women on collagen than on placebo showed measurable thickening Hwang 2026 - Hwang S, Won J, Kim S et al. Low-Molecular-Weight Collagen Peptide Supplementation Improves Cellulite Severity, Skin Elasticity, and Hair Shaft Diameter: A Clinical Study with Pharmacokinetic Evaluation. J Med Food. 2026;29(4):187-195., in the references below.

The trial measured how thick each hair was, not how many hairs grew. It tested one product, and I found no second trial that repeated it. Two of the five authors work for NEWTREE, a Korean health-food company, and the paper declares no competing interests.

A second trial enrolled 83 people with pattern hair loss or chronic shedding (telogen effluvium). Some took a tablet of fish collagen, amino acids, iron and selenium on top of their hair-loss drugs. Blinded photo scores improved more than on the drugs alone at 12 weeks Milani 2023 - Milani M, Colombo F. 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. Skin Res Technol. 2023;29(6):e13381., in the references below. There was no placebo, collagen was one ingredient of several, and two authors worked for the company selling the tablet.

Collagen peptides are sold as dietary supplements, which FDA does not approve before sale. More on the collagen evidence: collagen peptides for hair.

2. GHK-Cu and copper peptides: one trial, in a combination

The one placebo-controlled trial gave 45 men with male pattern hair loss a scalp spray to use once a day for 6 months. The spray combined copper-free GHK with 5-aminolevulinic acid (5-ALA). Hair counts rose by about 53 and 72 hairs in the two strength groups and by about 10 on placebo. Only the lower strength differed significantly from placebo, and hair length and thickness did not differ between groups Lee 2016 - Lee WJ, Sim HB, Jang YH et al. Efficacy of a Complex of 5-Aminolevulinic Acid and Glycyl-Histidyl-Lysine Peptide on Hair Growth. Ann Dermatol. 2016;28(4):438-43., in the references below.

Because GHK came paired with 5-ALA, and without its copper, the trial cannot say what GHK-Cu itself does. I found no trial of GHK-Cu on its own for hair. The rest is mixtures and lab work:

An open-label study injected a growth-factor mixture containing copper tripeptide-1 and thymosin beta-4 into the scalps of 1,000 patients. It had no comparison group, so no single ingredient can be credited Kapoor 2018 - Kapoor R, Shome D. Intradermal injections of a hair growth factor formulation for enhancement of human hair regrowth - safety and efficacy evaluation in a first-in-man pilot clinical study. J Cosmet Laser Ther. 2018;20(6):369-379., in the references below.
In the lab, AHK-Cu, a close copper-peptide relative of GHK-Cu, lengthened human hair follicles kept alive in a dish Pyo 2007 - Pyo HK, Yoo HG, Won CH et al. The effect of tripeptide-copper complex on human hair growth in vitro. Arch Pharm Res. 2007;30(7):834-9., in the references below.

GHK-Cu is a cosmetic ingredient, listed as Copper Tripeptide-1. FDA lists “restore hair growth” as a claim that makes a product a drug, so a cosmetic serum cannot legally promise regrowth. More: GHK-Cu (copper peptides) and what people who use GHK report.

3. Acetyl tetrapeptide-3: tested only in a blend

Acetyl tetrapeptide-3 is a signal peptide added to hair serums. The one trial I found tested it in a blend with biochanin A and ginseng extract. The blend was compared with 3% minoxidil in 32 men and women with mild to moderate pattern hair loss. After 24 weeks, terminal hair counts rose 8.3% on the blend and 8.7% on minoxidil, with no significant difference Lueangarun 2020 - Lueangarun S, Panchaprateep R. An Herbal Extract Combination (Biochanin A, Acetyl tetrapeptide-3, and Ginseng Extracts) versus 3% Minoxidil Solution for the Treatment of Androgenetic Alopecia: A 24-week, Prospective, Randomized, Triple-blind, Controlled Trial. J Clin Aesthet Dermatol. 2020;13(10):32-37., in the references below.

There was no placebo group, and the peptide was one of three actives. The result says the blend kept pace with 3% minoxidil in a small group, not that the peptide grows hair.

4. TB-500: hair growth in rats and mice only

Thymosin beta-4 stimulated hair growth in normal rats and mice, partly by helping hair-follicle stem cells migrate Philp 2004 - Philp D, Nguyen M, Scheremeta B et al. Thymosin beta4 increases hair growth by activation of hair follicle stem cells. FASEB J. 2004;18(2):385-7., in the references below. That work used the full thymosin beta-4 protein. TB-500 is a short synthetic fragment sold as a research chemical. I found no human hair study of either on its own. The only human study that included thymosin beta-4 was the uncontrolled scalp-injection mixture above. More: TB-500.

5. BPC-157: no hair studies found

A PubMed search on 3 October 2026 for BPC-157 with hair, alopecia or follicles returned one mouse burn-wound study and nothing on hair. The case for it rests on its blood-vessel effects in rats. It is a research chemical, not approved for human use. More: BPC-157.

6. CJC-1295, ipamorelin and MK-677: no hair data

The argument for growth-hormone peptides is indirect: they raise growth hormone and IGF-1, and sellers infer a hair effect from that. I found no study that measured hair with CJC-1295, ipamorelin or MK-677.

For MK-677 the worry usually runs the other way: see does MK-677 cause hair loss?. All three are research chemicals. More: CJC-1295 and ipamorelin.

How to check a hair-peptide claim

Did the study measure hair (count, thickness, standard photos), or only skin?
Was there a placebo group?
Was the peptide tested alone, or in a blend?
Is the product the one that was tested, at the same strength?

Of the human studies above, only the 114-woman collagen trial passes the first three.

Common questions

Does BPC-157 help hair growth?

I found no evidence either way. A PubMed search on 3 October 2026 found no study of BPC-157 and hair in people or animals. The closest result was a mouse burn-wound study. Claims that it helps hair borrow from its blood-vessel effects in rats, not from any hair result. It is a research chemical, not approved for human use.

Does GHK-Cu really regrow hair?

That has not been shown. I found no trial testing GHK-Cu on its own for hair. The one placebo-controlled trial used a scalp spray of copper-free GHK and 5-aminolevulinic acid in 45 men with pattern hair loss for 6 months. Hair counts rose more than on placebo at the lower strength, but hair thickness and length did not differ. In the lab, a related copper peptide lengthened hair follicles kept alive in a dish, which is not regrowth in people.

Do peptides for hair loss really work?

The human evidence is thin. Two peptides have one placebo-controlled hair trial each. Oral collagen peptides gave thicker hair shafts in 114 women. A GHK combination spray gave more hairs at one strength in 45 men. Neither result has been repeated in a second trial. The approved hair-loss drugs, minoxidil and finasteride, are not peptides.

What is the best peptide for hair loss?

I found no peptide approved to treat hair loss. Ranked by human evidence, oral collagen peptides and topical GHK products come first, each on the strength of one small trial. TB-500's parent protein has only rodent data, and I found no hair study of BPC-157, CJC-1295, ipamorelin or MK-677. Hair loss has many causes, so it is worth having a doctor check yours first.

Are injectable peptides better for hair than topical ones?

I found no trial comparing them. The placebo-controlled peptide hair trials used a supplement taken by mouth and a spray applied to the scalp. The injected mixtures studied for hair held several growth factors at once and had no comparison group, so they cannot show what any one peptide does. Injectable research peptides also carry purity and sterility questions that no regulator checks.

Do peptides help female hair thinning?

The largest peptide hair trial was in women. It enrolled 114 women aged 20 to 50 with self-reported thinning, who took a collagen peptide supplement or placebo for 24 weeks. Their hair shafts grew thicker on collagen. It measured thickness, not regrowth, and tested one product. The GHK trial enrolled only men.

What is the downside of taking peptides for hair?

For topical and oral products, the main cost is paying for claims no trial has tested. The GHK trial reported no side effects in any group. Injected research peptides such as BPC-157 and TB-500 have no human safety data for hair use, and no regulator checks that a vial matches its label.

References (12 sources)

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.