A small randomized split-face study reported eyebrow improvement with GHK-Cu serum in 18 people over 12 weeks [1]. Scalp evidence remains harder to interpret: a GHK blend without copper, a different copper peptide in laboratory follicles, and multi-ingredient regimens [2] [3]. Eyebrows, scalp pattern hair loss and beard growth are different outcomes.
The one human trial used a GHK blend, not GHK-Cu
The only randomized hair trial on the list tested ALAVAX, a complex of 5-aminolevulinic acid (5-ALA) and GHK, in 45 men with male pattern hair loss. The GHK in it had no copper [2].
The men used one of two strengths or a placebo for 6 months. Hair counts went up by 52.6 and 71.5 in the two ALAVAX groups, against 9.6 on placebo. Hair length and thickness didn't differ between the groups at 6 months, and no side effects were reported [2].
Two things to notice. The lower strength did better than the higher one, which a 45-person trial can't explain. And more hairs without thicker hairs is a modest result. The authors call the blend a possible "complementary" option, not a stand-alone treatment [2].
The lab study behind most claims used a different peptide
A 2007 lab study found that AHK-Cu, a related copper tripeptide, lengthened human hair follicles kept alive in culture [3].
AHK-Cu swaps one amino acid in GHK-Cu (alanine for glycine). In the study it also made dermal papilla cells, the cells that drive follicle growth, multiply. It lowered markers of cell death, though the drop in dying cells itself wasn't statistically significant [3]. That's useful biology. It isn't a person growing hair.
| Study | Molecule tested | Who or what | Size and length | Finding |
|---|---|---|---|---|
| Pyo 2007 [3] | AHK-Cu, a related copper tripeptide | Human hair follicles and cells in the lab | Lab only | Follicles lengthened; dermal papilla cells multiplied |
| Lee 2016 [2] | 5-ALA + GHK complex (no copper) | Men with pattern hair loss | 45 people, 6 months, placebo-controlled | Hair count up 52.6 and 71.5 vs 9.6 on placebo; no change in length or thickness |
| Kapoor 2018 [4] | Injected growth-factor mix that included copper tripeptide-1 | 1,000 people with hair loss | Open-label, followed to 1 year, no control group | Hair counts rose; no comparison group, so the copper peptide's part can't be told apart |
| Bertin 2018 [5] | Laser plus topical finasteride, growth factors and copper peptide | 4 people with pattern hair loss | Case series | All 4 improved; finasteride was part of the mix |
| Patel 2024 [6] | Scalp scrub plus a serum with copper tripeptide-1 and other ingredients | Adults with dandruff | Open-label, 15 days, maker-funded | Flaking improved; a dandruff study, not a hair-loss trial |
| Bo 2026 [1] | GHK-Cu serum | 18 participants with sparse eyebrows | Randomized, split-face, 12 weeks | Eyebrow count and diameter improved; small cosmetic study, not scalp or beard evidence |
Kapoor 2018 and Patel 2024 have no placebo group. Patel 2024 was run by a research firm and the serum's maker.
Does GHK-Cu block DHT?
No study shows that GHK-Cu blocks DHT. The proposed hair mechanism is follicle-cell growth and less cell death, and it comes from lab work [3].
PubMed searches for GHK-Cu with DHT, and for GHK with 5-alpha reductase, returned no records [8]. If DHT is what you want to target, finasteride is the drug that does it. Its label describes it as a 5α-reductase inhibitor for male pattern hair loss [9].
What the reviews conclude
A 2026 systematic review of 64 GHK-Cu records lists androgenetic alopecia as an area where well-designed human trials are still needed [7].
The same review calls the human GHK-Cu literature "thin and fragmented," mostly small cosmetic-cream trials. It also notes that about 35% of the primary papers include the peptide's discoverer or a colleague from his company as an author [7]. That's the backdrop for any hair claim you'll read: promising lab work, very little human testing.
Injections for hair: no controlled trial, and no legal route
No controlled human trial of injected GHK-Cu for hair was found. The one injected study on the list used a growth-factor mix with many ingredients and no control group [4].
Injectable GHK-Cu also has no legal compounding route in the US right now. FDA flagged injectable GHK-Cu for possible immune reactions in 2023 [11]. The full record is in injectable GHK-Cu's legal status. The topical form is different: it's in Category 1 of FDA's 503A list, so qualifying compounding may fall within the interim policy when its conditions are met [12].
Among telehealth programs, AgelessRx, Eden and HealthRX list a compounded topical GHK-Cu cream or foam.
The approved options to ask about first
Topical minoxidil (over the counter) and oral finasteride (prescription, for men) are FDA-approved for pattern hair loss. Both have labels that say what to expect and when.
- Minoxidil foam or solution. The men's foam label says it's used to regrow hair on the top of the scalp. It says some men need at least 4 months before they see results [10]. Women's versions are sold too.
- Finasteride (Propecia). The label says it's for male pattern hair loss in men only, and is not for women. It says that, in general, benefit takes three months or more of daily use [9].
A dermatologist or your prescriber can tell you which fits, and whether your hair loss is the pattern kind these labels cover. For timelines on copper peptides specifically, see how long GHK-Cu takes to work. Start with the 30-second match or the skin shortlist if you'd rather compare programs.
Beard growth
The cited clinical studies do not establish a beard-growth benefit. The eyebrow study should not be treated as a beard trial [1].
Curious about skin claims too? Same story, different body part: see GHK-Cu for acne.