GHK-Cu
Animal / in-vitro onlyGlycyl-L-histidyl-L-lysine copper(II)
Reported to modulate gene-expression networks involved in wound healing, collagen and elastin synthesis, antioxidant defence and inflammation. Most mechanistic work is gene-expression correlation analysis and topical skin work from a small set of investigators rather than controlled clinical trials.
GHK · Cu(II)
Not an approved drug. Regulated as a cosmetic ingredient for topical use; injectable use is unapproved and research-only.
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Melanotan II
Human trials (limited)MT-II
A non-selective melanocortin agonist that stimulates melanogenesis and central MC4R pathways. Human evidence is limited to a small 1996 pilot phase I study; unregulated supply carries documented safety risks.
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
Not approved in any jurisdiction. Sold illegally as a research chemical. Prohibited in sport (WADA S2).
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Matrixyl
Human RCTPalmitoyl pentapeptide-4 · Pal-KTTKS
A collagen-fragment mimic that prompts fibroblasts to increase collagen, fibronectin and glycosaminoglycan production. One randomised split-face human trial in photoaged skin supports the wrinkle claims.
Palmitoyl-KTTKS
Cosmetic ingredient. Not approved as a drug by FDA or EMA.
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Argireline
Human trials (limited)Acetyl hexapeptide-8 · acetyl hexapeptide-3
A hexapeptide marketed as a topical alternative to botulinum toxin, aiming to reduce acetylcholine release at the neuromuscular junction. Human studies are small and mostly manufacturer-adjacent.
Ac-EEMQRR-NH2
Cosmetic ingredient. Not approved as a drug.
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Afamelanotide
Approved drugMelanotan I · CUV1647 · Scenesse
A stabilised alpha-MSH analogue that increases skin eumelanin, licensed to extend pain-free sunlight exposure in erythropoietic protoporphyria. Long-term observational data support sustained benefit.
Ac-SYS-Nle-EH-(D-Phe)-RWGKPV-NH2
FDA-approved 2019 and EMA-approved 2014 (Scenesse) for erythropoietic protoporphyria. Grey-market 'Melanotan I' is the same molecule sold unregulated.
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SNAP-8
Animal / in-vitro onlyAcetyl octapeptide-3 · acetyl glutamyl heptapeptide-1
A cosmetic peptide marketed as a topical alternative to botulinum toxin. The mechanism is plausible in principle but published independent clinical evidence is essentially absent.
Ac-EEMQRRAD-NH2
Cosmetic ingredient, not a drug. No independently peer-reviewed human efficacy trial was located; most data are supplier-generated.
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Palmitoyl tripeptide-1
Human trials (limited)Pal-GHK · Biopeptide CL
Fibroblast studies and small, largely industry-sponsored human cosmetic trials suggest effects on collagen synthesis and wrinkle depth. Because it is almost always used in multi-ingredient blends, isolating its contribution is difficult and independent well-powered trials are lacking.
Palmitoyl-GHK
Regulated as a cosmetic ingredient, not a drug.
Primary sources