Home›The Library›Copper peptides
Copper peptides (GHK-Cu)
A copper-carrying peptide used in skincare to help skin rebuild collagen. One of about three peptides on the market with real human trial data behind it — and one of the most over-claimed.
On this page
In brief
Should you care? Probably yes, if firmness and fine lines are your concern. In one comparative trial, topical GHK-Cu increased collagen deposition in 70% of participants after a month — more than vitamin C or retinoic acid applied the same way in the same study.1 That's a measured result in real people, not a promise about your face.The short version
- What it does: signals skin to produce more collagen and elastin.
- Evidence: grade A — human trials, not just laboratory work.
- What it won't do: regrow hair, work as an injection, or survive being mixed with pure vitamin C.
What it actually is
GHK-Cu is three amino acids — glycine, histidine and lysine — holding onto a copper ion. Your body already makes it: it circulates in blood plasma, and levels fall substantially with age. That decline is where the interest comes from. The idea is that putting it back on skin restores a signal that used to be there.
On an ingredient list it appears as copper tripeptide-1. If a product lists that, this is what it is. Functionally it’s classed as a carrier peptide — see how that differs from signal and neurotransmitter peptides.
What the evidence supports
In one comparative human trial, topical GHK-Cu increased collagen deposition in 70% of participants after one month of daily use — versus 50% for vitamin C and 40% for retinoic acid applied under the same conditions.1 A separate 12-week trial in 67 women found twice-daily GHK-Cu cream significantly thickened the epidermis and dermis, stimulated keratinocyte proliferation, and improved skin density, elasticity and moisture.1
That is a stronger base than almost anything else sold as a "peptide" in skincare, which is why it carries our top grade. It is not, however, a large body of independently repeated trials — which is why the grade is A and not something stronger. We would rather say that than imply more certainty than exists.
How to read these numbers
Collagen deposition and skin thickness are measurements taken in skin. That is not the same as a visible change in the mirror, and how much you see depends on the concentration used, how the product is formulated, how well it penetrates and how long you keep going. Grade A means the evidence is real and it is in humans — not that the result is guaranteed for you.
How long it takes
| Timeframe | What people typically report |
|---|---|
| 2–4 weeks | Texture and hydration begin to shift — the earliest thing you would notice |
| 8–12 weeks | Firmness and fine lines; this is the window the collagen research covers |
| 12–16 weeks | Results generally plateau. Longer is not better; consistent is better |
If you are going to judge whether it works for you, judge it at twelve weeks. Three weeks is not a trial, it is an opinion.
What it does not do
Claims the evidence does not carry
- Regrow hair. Widely claimed, and the trail leads back to animal work and patent filings rather than human trials.3 Treat hair claims as marketing.
- Work as an injection. All the human data here is topical. Injectable GHK-Cu is not an approved medicine and we do not recommend or sell it.
- Survive pure vitamin C in the same layer. This is chemistry rather than caution — see how to use it.
- Replace sunscreen. Nothing in this category does. Collagen built overnight can be undone at lunchtime.
Is it safe?
Topical copper peptides are generally well tolerated, with little reported irritation — one reason they are often suggested for people who cannot get on with retinoids. As with any new active, patch test first: a small amount on the inner forearm for a few days before it goes near your face.
They suit most skin types, and are most often used by people with dry to mature skin noticing a loss of firmness. Read the full breakdown of possible side effects →
Where it's legal
As a topical cosmetic ingredient, GHK-Cu is lawful in the US, UK and EU under the usual cosmetic safety and labelling rules.4 Products may make appearance claims — "reduces the appearance of fine lines" — but not claims to treat a condition. Injectable forms fall outside that framework entirely.
What to look for in a product
- The percentage on the label. Not "peptide complex". If a brand will not state it, assume it is low.
- A stated pH between 5.0 and 6.5. Why this matters.
- No EDTA or strong chelators in the same formula — they strip the copper out and inactivate it.
- A batch certificate of analysis you can actually look at.
References
- "Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data" — review summarising the comparative collagen-deposition trial (GHK-Cu vs vitamin C vs retinoic acid, one month) and a 12-week, 67-participant twice-daily cream trial. pmc.ncbi.nlm.nih.gov/articles/PMC6073405
- Badenhorst T, Svirskis D, Merrilees M, Bölke L, Wu Z (2016), "Effects of GHK-Cu on MMP and TIMP Expression, Collagen and Elastin Production, and Facial Wrinkle Parameters," Journal of Aging Science 4:166. DOI: 10.4172/2329-8847.1000166
- US Patents 5,120,831, 5,177,061, 5,538,945 and 5,550,183 (Pickart) — patent filings connecting GHK-Cu to hair follicle activity in mice, cited here as the origin of the hair-growth marketing claim, not as evidence the claim holds in humans. See do peptides work for hair growth?
- US FDA cosmetic labelling and claims guidance; EU Cosmetic Products Regulation 1223/2009.