Research / Published Sep 8, 2026 / Reviewed Sep 27, 2026 / 8 min read
Peptides for Hair Growth: GHK-Cu, AHK-Cu, PTD-DBM and PP405
Written by Aaron CuhaReviewed Sep 27, 2026
What happened when people used peptides for hair loss: copper peptide scalp injections in thousands of clinic patients, a GHK hair study in 45 men, what users report, and how that compares with minoxidil and finasteride. Plain English, every study linked.
Key takeaways
- No peptide is an approved hair-loss drug. GHK-Cu and AHK-Cu are sold as skin and hair care ingredients. PTD-DBM has only been tried in mice. PP405 is a new hair drug still being tested, and it is not a peptide.
- The biggest copper peptide results come from hair clinics. In Japan, 18,918 men got monthly scalp injections that included copper peptide, and nearly all were happy with the result. In India, 1,000 people got a similar mix and 83% shed less hair. Both groups were getting other hair treatments too.
- In a Korean study, 45 men used GHK mixed with another ingredient, 5-ALA, on the scalp for six months. Hair counts rose by about 53 to 72 hairs, against about 10 on a dummy treatment.
- Users say copper peptide works best on hair that is thinning but still growing. They report needing about six months, usually alongside minoxidil and microneedling.
- For comparison, the two approved drugs: minoxidil added about 19 hairs per square centimetre in a year-long study of 393 men. Finasteride added about 107 hairs in a one-inch circle in a year, in 1,553 men.
Do peptides regrow hair?
Direct answer
Copper peptides have been used for hair on thousands of people. Most clinic patients given scalp injections that included copper peptide shed less hair, and 45 men using GHK with another ingredient grew more hairs than men on a dummy treatment. In each case other ingredients or drugs were involved. Users report the best results after six months alongside minoxidil.
No peptide is approved as a hair-loss drug anywhere. GHK-Cu and AHK-Cu are sold in serums and shampoos, and skin and hair products don't have to prove they work before they are sold. PTD-DBM is sold as a research peptide. PP405 is a new drug still being tested and can't be bought. Peptides like GHK are natural and can't be patented, so no drug company pays for big studies of them. That is why the best records are hair clinics and what users report.
What happened to people who used them
| What | Who | What they got | What happened | Worth knowing |
|---|---|---|---|---|
| Copper peptide in a scalp injection, Japan | 18,918 men, 2011 to 2017 | Monthly scalp injection including copper peptide, 6 months or more | Every man's photos improved. 96% happy at 6 months, 80% at a year. About 4 in 100 had minor pain or bleeding. | Also taking finasteride and minoxidil |
| Copper peptide in a scalp injection, India | 1,000 men and women, 2018 | Scalp injections every 3 weeks, 8 times | 83% shed less hair. Hair counts still up at a year. 75% felt it helped. | The mix also held growth factors and thymosin beta-4 |
| GHK with 5-ALA, Korea | 45 men, 2016 | Daily scalp treatment for 6 months, two strengths, or a dummy | About 53 and 72 more hairs, against about 10 on the dummy. No change in length or thickness. No side effects. | Mixed with 5-ALA. The weaker strength did better. |
| PP405 (not a peptide) | 78 men and women, 2025 | Scalp treatment once a day for 4 weeks, or a dummy | 31% of men with more hair loss had over 20% more hair at 8 weeks, against none on the dummy | Company announcement, not yet published in a journal |
| Minoxidil 5% (approved) | 393 men, 2002 | Twice a day for 48 weeks | About 19 more hairs per square centimetre, against about 4 on the dummy | The standard to beat |
| Finasteride 1 mg (approved) | 1,553 men, 1998 | One pill a day for 1 to 2 years | About 107 more hairs in a one-inch circle than the dummy at a year, 138 at two years | The standard to beat |
Studies: Japan clinic, 2018, India clinic, 2018, Korea, 2016, minoxidil, 2002, finasteride, 1998. The copper peptide guide has the skin and wound results too.
What users say about GHK-Cu for hair
Direct answer
Users say nothing visible happens in the first four weeks. The people who are happy with it ran it for about six months, usually alongside minoxidil and microneedling, and almost nobody says it worked alone. Experienced users say it helps hair that is thinning but still growing, not bald patches that stopped growing long ago.
- Most people put it on the scalp rather than injecting it, often mixed into water and sprayed on.
- Injecting it is described as painful, with a blue bruise at the spot for two or three days. That is the most common complaint.
- The same people often say their skin improved more than their hair.
- Stories of grey hair darkening again come up, but as single accounts rather than a common pattern.
- Few side effects are reported beyond the injection spot.
These are patterns across many forum posts on ExcelMale, LongeCity and Bluelight, read in September 2026. They are summaries, not quotes.
AHK-Cu, the copper peptide sold for hair
AHK-Cu has one published study. In 2007, researchers kept human hair follicles alive in a dish, and the follicles grew longer with AHK-Cu (Archives of Pharmacal Research, 2007). Nobody has published what happens when a person uses it.
The 1993 rat study often quoted for GHK-Cu
Product sites often say GHK-Cu grew hair like minoxidil in a 1993 study. The peptide in that study was PC1031, a different copper peptide, and it was tested on rats, where it made the hair roots bigger (Journal of Investigative Dermatology, 1993). The monkeys in the same paper were given minoxidil and other drugs, not a peptide. So that study is not about GHK-Cu.
PTD-DBM: mice only so far
Direct answer
PTD-DBM releases a brake on the signal that tells hair roots to grow. In a 2017 study, mice given it regrew hair faster, and with a second drug it grew new hair roots inside healing wounds. The researchers also found more of that brake in balding human scalps. Nobody has published results in people.
The study came from Yonsei University in Korea (Journal of Investigative Dermatology, 2017). It is one of the more interesting ideas in hair research, but it has not been tried on people. Anything sold under the name is a research peptide, so check what is actually in the vial. Our guide to lab certificates explains how.
PP405: a new hair drug, not a peptide
Direct answer
In June 2025, the company Pelage announced that 78 men and women used PP405 or a dummy treatment on the scalp once a day for four weeks. At eight weeks, 31% of men with more hair loss had over 20% more hair, against none on the dummy. None of it showed up in the blood. A bigger study was planned for 2026.
PP405 wakes up resting hair-root cells. It is here because it is the newest hair treatment with results in people. The numbers come from the company's announcement, not yet a journal paper. Four weeks of use is short for hair, so the bigger study will say more.
The bottom line
Copper peptides have a real track record in people for hair, mostly from clinics that combined them with other treatments, plus a steady stream of user reports. Users describe it as a slow helper for thinning hair, used for months alongside minoxidil, rather than a stand-alone fix. AHK-Cu and PTD-DBM have not been published in people yet. The approved drugs, minoxidil and finasteride, remain the ones with the largest records.
Frequently asked questions
Does GHK-Cu work for hair loss?
Thousands of hair clinic patients given scalp injections that included copper peptide shed less hair, and 45 men using GHK with 5-ALA grew about 53 to 72 more hairs in six months. Those people had other ingredients or drugs too. Users say it helps thinning hair over about six months, usually with minoxidil and microneedling.
Is PP405 a peptide?
No. PP405 is a new hair drug from Pelage that wakes up resting hair-root cells. In a 2025 study of 78 people, 31% of men with more hair loss had over 20% more hair at eight weeks, against none on a dummy treatment. A bigger study was planned for 2026.
Has PTD-DBM been tested in humans?
No. The only study is from 2017, in mice. They regrew hair faster, and with a second drug grew new hair roots inside wounds. Nobody has published results in people.
How much hair does minoxidil or finasteride regrow?
In a year-long study of 393 men, 5% minoxidil added about 19 hairs per square centimetre, against about 4 on a dummy. In 1,553 men, finasteride added about 107 hairs in a one-inch circle at a year compared with a dummy, and 138 at two years.
Compound profiles mentioned
- GHK-CuLimited. People have taken it in a published study, but fewer than 100 of them. 2 completed trials, 99 people given it.Healing & Recovery
- AHK-CuAnimal or lab only. Only animal or lab studies on this page. No study in people yet. 1 animal study, 1 lab study, no human study.Cosmetic
- PTD-DBMAnimal or lab only. Only animal or lab studies on this page. No study in people yet. 2 animal studies, no human study.Cosmetic
- MatrixylModerate. At least one finished study in people, and at least 100 people who took it. 2 completed trials, 114 people given it.Cosmetic
- ArgirelineModerate. At least one finished study in people, and at least 100 people who took it. 4 completed trials, 155 people given it.Cosmetic
Sources
- Study in people2018
Androgenetic Alopecia Treatment in Asian Men
Japanese clinic, 18,918 men on finasteride, minoxidil and a monthly scalp injection including copper peptide. Every man's photos improved; 96% happy at 6 months, 80% at a year; minor problems in 4.2%.
Journal of Clinical and Aesthetic Dermatology - Study in people2018
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
Indian clinic, 1000 people given scalp injections of growth factors, thymosin beta-4 and copper peptide. 83% shed less hair; hair counts still up at a year.
Journal of Cosmetic and Laser Therapy - Study in people2016
Efficacy of a Complex of 5-Aminolevulinic Acid and Glycyl-Histidyl-Lysine Peptide on Hair Growth
45 men, GHK with 5-ALA on the scalp daily for 6 months: about 53 and 72 more hairs on two strengths, against about 10 on a dummy. No side effects.
Annals of Dermatology - Study in people2002
A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men
393 men, 48 weeks: about 19 more hairs per square centimetre on 5%, 13 on 2%, 4 on a dummy.
Journal of the American Academy of Dermatology - Study in people1998
Finasteride in the treatment of men with androgenetic alopecia
1,553 men, 1 mg a day: about 107 more hairs in a one-inch circle than a dummy at a year, 138 at two years.
Journal of the American Academy of Dermatology - Study in people2025
Pelage Pharmaceuticals announces positive Phase 2a clinical trial results for PP405 in regenerative hair loss therapy
78 people: 31% of men with more hair loss had over 20% more hair at 8 weeks, against none on a dummy.
Pelage Pharmaceuticals - Lab (cells in a dish)2007
The effect of tripeptide-copper complex on human hair growth in vitro
Human hair follicles kept alive in a dish grew longer with AHK-Cu.
Archives of Pharmacal Research - Animal study1993
Chemical agents and peptides affect hair growth
A copper peptide called PC1031, not GHK-Cu, made hair roots bigger in rats, similar to minoxidil.
Journal of Investigative Dermatology - Animal study2017
Targeting of CXXC5 by a competing peptide stimulates hair regrowth and wound-induced hair neogenesis
Mice given PTD-DBM regrew hair faster; with a second drug, new hair roots grew inside wounds.
Journal of Investigative Dermatology
Read next
Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use. Sellers named on the price pages are ranked by certificate tier, then price, and any affiliate income is disclosed there. Naming a seller is not a recommendation to buy or use anything.