Peptides for Hair Loss: AHK-Cu vs GHK-Cu vs PTD-DBM

AHK-Cu, GHK-Cu and PTD-DBM: the evidence compared

A hair follicle growing longer in a culture dish is a useful experimental result. It does not tell us whether a compound will restore hair density on a person's scalp. That gap matters when reading about AHK-Cu, GHK-Cu and PTD-DBM, because the names often appear beside claims that go further than the papers.

The comparison below separates the material tested, the experimental model and the outcome measured. It also distinguishes GHK-Cu from a related compound that has reached a small human study. As of October 25, 2026, our source search identified no published controlled human hair-loss trial establishing the effect of AHK-Cu, GHK-Cu itself or PTD-DBM.

These are different research questions. AHK-Cu was examined directly in isolated follicles. GHK-Cu needs careful separation from neighbouring copper-peptide and GHK literature. PTD-DBM was designed to interfere with a specific protein interaction. The available evidence does not support ranking them by how much hair a person would regrow.

AHK-Cu: what the 2007 study found

AHK-Cu is the copper complex of alanine, histidine and lysine. Pyo and colleagues tested it in isolated human hair follicles and cultured dermal papilla cells, which help regulate follicle growth. The study reported greater follicle elongation and cell proliferation under its experimental conditions.^[1]

The authors also examined cell-death markers. Some molecular measurements changed in a direction consistent with reduced apoptosis. However, the reduction in the measured number of apoptotic cells was not statistically significant. Describing the study simply as proof that AHK-Cu prevents follicle-cell death would lose that qualification.

This was human-derived tissue research, not a trial in people with hair loss. It did not establish scalp hair density, a durable cosmetic outcome or a patient safety profile. The wording “human hair growth” in the paper's title describes the origin of the follicles; it should not be read as evidence that volunteers received the compound.

For this review, the 2007 paper is the direct AHK-Cu follicle study we could verify. A wider evidence base would need replication and studies that answer the clinical questions left open.

GHK-Cu: check which molecule the citation tested

GHK-Cu contains glycine, histidine and lysine bound to copper. AHK-Cu starts with alanine instead of glycine. Those names differ by one letter, but a paper about one compound cannot serve as direct evidence for the other.

This is the first check to make when a GHK-Cu hair-growth claim links to Pyo's 2007 paper. The abstract explicitly identifies AHK-Cu. The citation may be relevant background on copper peptides, but its follicle results belong to AHK-Cu.

The human study used ALAVAX, not GHK-Cu

A 2016 paper in Annals of Dermatology evaluated ALAVAX, a compound combining 5-aminolevulinic acid (5-ALA) with GHK. Its reported chemical structure contains no copper. The study was randomised, double-blind and placebo-controlled, and followed men with pattern hair loss for six months.^[2]

The abstract reports 45 participants. Hair-count measurements improved in the active groups, and one active group differed significantly from placebo on the reported ratio of hair-count change. Hair length and thickness did not differ significantly among the groups at six months.

There are reporting details worth retaining. The methods list group sizes of 15, 14 and 14, while the baseline table lists 15 per group. Counts were taken within a circle 1 cm in diameter; repeating those figures as hairs per square centimetre would change the unit. This small paper deserves to be read on its own terms.

ALAVAX provides human evidence for the tested compound and formulation. It does not isolate the contribution of GHK, establish a GHK-Cu effect, or validate a different finished product. Calling it “the GHK-Cu hair-loss trial” would erase the most important detail in the comparison.

Why mixed protocols cannot settle the GHK-Cu question

The same attribution problem applies whenever a report combines several ingredients or procedures. A change observed after the whole programme belongs to that programme. Without an appropriate comparison group, the contribution of one ingredient remains unresolved.

For a GHK-Cu-specific claim, look for the exact copper complex in the methods, a comparator that isolates its contribution, and a hair outcome measured in patients. A general skin study, an isolated-follicle experiment and a multi-ingredient treatment report answer different questions.

Our separate GHK-Cu research vial and copper-peptide serum comparison explains why ingredient evidence also needs to be distinguished from finished-product evidence.

PTD-DBM: CXXC5 and the Wnt pathway

PTD-DBM takes a different approach. Its name refers to a protein transduction domain joined to a Dishevelled-binding motif. The peptide is designed to interfere with the interaction between CXXC5 and Dishevelled, a protein involved in Wnt signalling.

The 2017 experiments

Lee and colleagues reported higher CXXC5 expression in miniaturised follicles and associated tissue from human balding scalps. Their work then examined the pathway in human dermal papilla cells and mice. Disrupting the CXXC5–Dishevelled interaction increased Wnt/β-catenin signalling and promoted hair regrowth and wound-induced follicle formation in the experimental models.^[3]

The human scalp observations helped connect the target to hair-loss biology. They were not a treatment trial. Likewise, new follicles appearing in wounded mouse skin do not establish that an adult human scalp with pattern hair loss would respond in the same way.

The 2023 follow-up and a separate small molecule

A follow-up paper examined the relationship between prostaglandin D2 (PGD2), CXXC5 and reduced Wnt signalling. PTD-DBM countered PGD2-associated suppression in cell and mouse experiments. The authors also studied wound-induced follicle formation.^[4]

The paper includes experiments with KY19382, a separate small molecule that inhibits both CXXC5-related and GSK-3β functions. Its DHT-model results should not be presented as though they were all obtained with PTD-DBM. Sharing a pathway does not make two experimental agents interchangeable.

These papers give PTD-DBM a specific mechanistic rationale. They leave open whether it reaches the relevant target in a suitable human formulation, what exposure would be tolerable, and whether any response persists. A pathway result cannot answer those questions by itself.

Research independence and commercial interests

The 2017 and 2023 papers come from an overlapping Yonsei-linked research programme. The 2023 disclosure states that Kang-Yell Choi is CEO of CK Regeon, which holds a licence to develop the pathway activator described in that publication. It also states that the company had no role in the study's design, analysis or publication decision.^[4]

That relationship belongs in an evidence review. It does not invalidate the experiments, but it makes independent replication particularly useful. Two papers from an overlapping programme should not be counted as two independent clinical confirmations.

Human trials and the claimed PTD-DBM–minoxidil comparison

We could not verify the claimed “40-patient PTD-DBM versus minoxidil” randomised trial. The searches used for this review did not produce a matching primary paper or a ClinicalTrials.gov record. We have therefore excluded its alleged results from the comparison.

A traceable report would need enough information to identify the study: authors, journal or registry identifier, the actual intervention, participant numbers and outcomes. A repeated percentage or before-and-after image does not supply that information.

The October 25, 2026 ClinicalTrials.gov search for AHK-Cu, GHK-Cu and PTD-DBM returned three records concerning ageing, circulating peptide levels or skin wounds. None was a hair-loss efficacy trial. This search is a dated check of one registry, not proof that every possible unpublished or differently named study has been excluded.^[5]

It is also important to distinguish a registered trial from published results. A record can describe work that is planned or recruiting. Even a completed study needs accessible results before it can support a claim about hair regrowth.

On the evidence reviewed here, there is no basis for saying that any of these three compounds matches or outperforms minoxidil in people. That comparison requires a human trial designed to test it.

How to read a peptide hair-growth claim

Start with the methods rather than the headline. The following checks help separate a useful experimental finding from a claim the study never tested.

• Match the substance. AHK-Cu, GHK, GHK-Cu, ALAVAX and KY19382 are different materials. Keep the name in the claim aligned with the name in the experiment.
• Identify the model. Cultured cells, an isolated human follicle, mouse skin and a treated patient provide different kinds of evidence.
• Read the outcome and comparator together. Hair length, hair count, shaft thickness and a signalling marker are separate outcomes. Improvement from baseline is not automatically superiority to placebo.
• Check who produced the evidence. Follow-up work adds information, while independent replication tests whether the result holds outside the originating programme.

For laboratory procurement, the material's identity and analytical documentation are separate from the biological claim. A purity result addresses the sample analysed. It cannot demonstrate hair regrowth, clinical safety or effectiveness. Our COA reference guide explains how to read those documents.

Remy Research supplies materials for in-vitro laboratory research only, not for human or veterinary use. The published experiments discussed here are studies of their own test materials. They are not results obtained with products sold by Remy Research. Catalogue listings and a research-use label do not establish a human treatment.

The useful conclusion is specific: AHK-Cu has a directly relevant follicle experiment; the GHK-Cu claim needs careful citation checking; and PTD-DBM has a defined preclinical mechanism with follow-up work. Controlled human hair-loss evidence remains the missing step for the three compounds themselves.