Copper and cosmetic peptides

Most of these are cosmetic ingredients made for creams and serums, and the strongest evidence for any of them is small, short skin studies. Injected use, including GHK-Cu and the GLOW and KLOW blends, has never been tested in people.

Compounds: 7
Approved drug: 0
Human studies: 4
Preclinical: 1
Blends: 2

Members

Copper peptides

Copper-carrying tripeptides. GHK occurs naturally in human blood; AHK-Cu is a synthetic relative used in hair serums.

Compound	What it is	Approval	Evidence	How often	Half-life	Sport
GHK-Cu	Copper peptide	Not approved	Human studies	Once daily	Not measured	Likely banned
AHK-Cu	Copper peptide (hair and skin)	Not approved	Preclinical	Once daily (topical)	Not measured	Not banned

Wrinkle peptides used on the skin

Topical-only ingredients: Argireline and SNAP-8 copy part of a nerve-signal protein, and Matrixyl copies a collagen fragment.

Compound	What it is	Approval	Evidence	How often	Half-life	Sport
Argireline	Cosmetic anti-wrinkle peptide	Not approved	Human studies	Twice daily (topical)	Not measured	Not banned
SNAP-8	Cosmetic anti-wrinkle peptide	Not approved	Human studies	Twice daily (topical)	Not measured	Not banned
Matrixyl	Cosmetic collagen-signal peptide	Not approved	Human studies	Twice daily (topical)	Not measured	Not banned

Blends with GHK-Cu

Injectable mixes of GHK-Cu with BPC-157 and TB-500; KLOW adds KPV. Neither blend has been studied.

Compound	What it is	Approval	Evidence	How often	Half-life	Sport
GLOW blend	Skin and repair blend	Blend	Blend	Once daily	See each part	Banned
KLOW blend	Skin, repair and anti-inflammatory blend	Blend	Blend	Once daily	See each part	Banned

Approval, evidence, half-life and sport status restate each compound’s own page, where the sources are listed. Select a name for doses, side effects and studies.

How they work

GHK is a three-amino-acid peptide found in human blood that binds copper tightly and is thought to carry it into cells. In cell and animal studies, GHK-Cu raised collagen production by fibroblasts (the skin’s collagen-making cells), sped wound healing and encouraged new blood vessels. AHK-Cu’s only published study found it lengthened donated human hair follicles kept alive in a lab dish. Animal

Argireline (acetyl hexapeptide-8) and SNAP-8 (acetyl octapeptide-3) copy the start of SNAP-25, a protein nerve endings use to release the chemical signals that make muscles contract. In lab tests they disrupted that release machinery, weakly, which is why they are marketed against expression lines. They are not botulinum toxin, and in donor skin almost none of the Argireline applied got past the outer layer. Animal

Matrixyl’s peptide, KTTKS, is a five-amino-acid piece of type I procollagen, the raw form of skin’s main collagen. In cell studies it made fibroblasts produce more collagen and fibronectin, another structural protein. A palmitic acid tail helps it into skin: in mouse skin a little reached the dermis, the deeper layer, though skin enzymes broke it down quickly. Animal

What’s shown in people is small and topical: a GHK-Cu wound gel that sped healing of diabetic foot ulcers, short cream studies, a 60-person, 4-week Argireline trial, and one 93-woman split-face trial of Matrixyl. None shows how the peptides act in living skin, and injected use, including the GLOW and KLOW blends, has never been tested in people. Trial

What they have in common

Made for the skin, not for injection

Precaution

Argireline, SNAP-8, Matrixyl and AHK-Cu are cosmetic ingredients sold in creams and serums, which aren’t sterile, and none has been tested by injection. GHK-Cu is used both ways, but only its topical forms have human data. FDA has flagged possible immune reactions from clumped peptide and impurities in injectable GHK-Cu.

Little reaches deep skin

Animal

How far these peptides get is the open question. In donor skin, nearly all Argireline stayed on the surface or in the outermost layer, and in mouse skin only a little Matrixyl reached the dermis. How much of the copper peptides passes through human skin hasn’t been measured.

Irritation

Community

The compound pages list skin irritation or redness for the topicals; the Matrixyl and eyelid-spasm Argireline trials reported no significant problems. Injected GHK-Cu commonly stings, in community reports. The pages suggest a patch test first and keeping products out of the eyes.

Copper cautions

Precaution

GHK-Cu, AHK-Cu, GLOW and KLOW all carry copper. Their pages advise avoiding them with Wilson’s disease or other copper disorders, in which the body can’t clear copper normally; build-up from repeated injections is a theoretical concern. True copper allergy is rare, but it happens.

Doubling up with the blends

GLOW and KLOW both contain 50 mg of GHK-Cu with 10 mg each of BPC-157 and TB-500, so using either alongside GHK-Cu, or the two blends together, doubles those doses. The stack check flags the same peptide arriving from two vials.

Status and sport

None is an approved drug; all are sold as cosmetic ingredients or research vials. Topical use isn’t on WADA’s 2026 list, but injected GHK-Cu falls under its S0 rule for unapproved drugs, and GLOW and KLOW contain BPC-157 and TB-500, both named on the list.

How they differ

What they target

Animal

GHK-Cu: collagen-making cells, wound healing and blood vessel growth in lab work. AHK-Cu: hair follicles in a dish. Argireline and SNAP-8: the nerve-to-muscle signal. Matrixyl: collagen production. The blends add BPC-157 and TB-500, plus KPV in KLOW, all with mostly animal data.

Route

Community

Argireline, SNAP-8, Matrixyl and AHK-Cu are topical only. GHK-Cu is applied to skin or, in community use, injected. GLOW and KLOW are injected, with each draw sized by its GHK-Cu share, commonly 1–2 mg.

Strength labels that mislead

Figures like “10% Argireline” or “3–10% SNAP-8” refer to dilute branded or supplier solutions, not pure peptide. Matrixyl’s only peer-reviewed trial used 3 ppm, and Matrixyl 3000 is a different product, a blend of palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7.

Human evidence

Trial

GHK-Cu: a wound-gel trial and small cream studies, one reported only as a conference poster. Argireline: several small trials, the largest 60 people for 4 weeks. Matrixyl: one 93-woman, 12-week trial. SNAP-8: supplier tests and two multi-ingredient patch studies. AHK-Cu: one lab study. GLOW and KLOW: none.

History

1973A three-amino-acid peptide from human blood, now known as GHK, was reported to keep liver cells alive longer in the lab.
1988GHK bound to copper (GHK-Cu) was shown to raise collagen production by fibroblasts in culture.
1994A GHK-Cu gel improved healing of diabetic foot ulcers in a randomized, evaluator-blinded, placebo-controlled trial.
2002Argireline was designed to mimic the start of SNAP-25 and was shown in lab tests to weakly block nerve signal release.
2005A 12-week split-face trial in 93 women found a Matrixyl moisturizer improved fine lines more than the same moisturizer without it.

Comparisons and guides

Questions

What is GHK-Cu?

A copper-binding peptide made of three amino acids, found naturally in human blood and sold in skin care as copper tripeptide-1. In cell and animal studies it raised collagen production and sped wound healing, and small studies tested it in creams and a wound gel. Injected GHK-Cu has never been tested in people.

Does Argireline work like Botox?

Only loosely. Both interfere with how nerves signal muscles to contract, but in lab tests Argireline’s effect was much weaker than botulinum toxin’s, and in donor skin almost none passed the outer layer. In its largest trial, 60 people for 4 weeks, wrinkle grading improved in 48.9% vs 0% on placebo. It isn’t an injectable and isn’t botulinum toxin.

Can cosmetic peptides be injected?

Argireline, SNAP-8, Matrixyl and AHK-Cu are made as cosmetic ingredients, not sterile drugs, and none has been tested by injection. GHK-Cu is injected in community use and sold in the GLOW and KLOW blends, but no study has tested injected GHK-Cu or either blend in people, and FDA has flagged immune-reaction risks from impurities in injectable GHK-Cu.

What’s the difference between GLOW and KLOW?

KLOW is GLOW plus KPV. Both contain 50 mg of GHK-Cu with 10 mg each of BPC-157 and TB-500; KLOW adds 10 mg of KPV, an anti-inflammatory fragment of alpha-MSH. Neither blend has been studied, and the added peptides have mostly animal data. Both carry copper, so their pages advise avoiding them with Wilson’s disease.

Is Matrixyl the same as Matrixyl 3000?

No. Matrixyl is palmitoyl pentapeptide-4 (pal-KTTKS), tested mainly in one peer-reviewed trial: 93 women, 12 weeks, one half of the face, at 3 ppm. Matrixyl 3000 is a blend of two other peptides, palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7, and the Matrixyl page doesn’t cover it.

Sources

Pickart and Thaler, a tripeptide in human serum that prolongs survival of normal liver cells (Nat New Biol 1973) PMID 4349963
Maquart et al., GHK-Cu stimulates collagen synthesis in fibroblast cultures (FEBS Lett 1988) PMID 3169264
Mulder et al., GHK-Cu gel in diabetic foot ulcers, randomized trial (Wound Repair Regen 1994) PMID 17147644
Pyo et al., AHK-Cu and human hair growth in vitro (Arch Pharm Res 2007) PMID 17703734
Blanes-Mira et al., design and lab mechanism of Argireline (Int J Cosmet Sci 2002) PMID 18498523
Kraeling et al., penetration of acetyl hexapeptide-8 into human and guinea pig skin (Cutan Ocul Toxicol 2015) PMID 24754410
Wang et al., randomized placebo-controlled Argireline trial in Chinese adults (Am J Clin Dermatol 2013) PMID 23417317
Robinson et al., 12-week split-face trial of palmitoyl pentapeptide (Int J Cosmet Sci 2005) PMID 18492182
Choi et al., skin stability and permeation of KTTKS and palmitoyl-KTTKS (Biomol Ther 2014) PMID 25143811
FDA, bulk drug substances that may present significant safety risks: GHK-Cu for injection (April 2026)

Each compound’s page lists the sources for its own doses, status and studies.

By Vial Guide editorsLast reviewed October 7, 2026

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