Skin, hair & cosmetic

Peptides appear in cosmetic and appearance-related contexts ranging from skin ageing and wound repair to pigmentation. The evidence and the risk profile vary enormously between them.

GHK-Cu (copper tripeptide) is a long-standing topical cosmetic ingredient with a real mechanistic literature in skin biology (collagen and extracellular-matrix support, wound healing, and antioxidant signalling), plus some small human cosmetic studies (and some controlled studies that were negative). Its topical use is generally considered well tolerated; injectable "research" use has no human trials.

Melanotan II is a very different case: a melanocortin agonist used non-medically for tanning (and erectile effects). It is not approved anywhere, has been the subject of repeated regulator warnings, and carries a notably serious risk profile: priapism, nausea, changes to moles and a melanoma concern, and reports of rhabdomyolysis. It should not be confused with afamelanotide (Melanotan I / Scenesse), a related but approved drug for a rare photosensitivity disorder.

Conditions people ask about

Popular videos and high-claim shop pages in this area promise to "reverse" or "cure" hair loss with copper-peptide or "repair-peptide" protocols — that framing is not supported. No compound on this site is an approved treatment for any condition below, and dramatic reversal claims lack controlled human evidence. The notes here exist to answer common searches honestly, not to guide treatment. Pattern hair loss is a progressive, androgen-driven condition that needs a proper diagnosis and a licensed clinician (a dermatologist); a research peptide is not a substitute for that.

Hair loss (androgenetic alopecia)

Popular videos and peptide-shop pages frame androgenetic alopecia as "reversible" with a copper-peptide or "repair-peptide" protocol, often claiming results that rival or beat minoxidil and can "wake up dead follicles." The evidence reality is that no peptide is an approved treatment for androgenetic alopecia anywhere — the only regulator-approved options are topical minoxidil, oral finasteride, and low-level laser devices, and none of the compounds below has a large, confirmatory human trial for hair regrowth; claims that any of them can regrow hair on long-dormant follicles have no controlled human evidence. [Human] The peptide most often cited, GHK-Cu, is a naturally occurring copper-binding tripeptide sold as a cosmetic/research ingredient and the most-studied here for hair, with small topical trials (some dating to the 1990s "Tricomin" era) suggesting modest increases in hair count and a plausible mechanism — raising VEGF and lowering TGF-β1 in dermal fibroblasts — but a 2025 review still counted only a handful of randomized trials and no large placebo-controlled monotherapy trial, so its status is best described as investigational and disputed rather than proven, and it is discussed as an adjunct, not a proven treatment. [Human][In vitro] Thymosin beta-4 is the full-length peptide behind the "stem-cell activation" claims; the supporting work (Philp 2004, Gao 2015) showed accelerated hair regrowth in depilated mice by activating follicle stem cells, but there is no human trial for hair loss, so its status here is preclinical only. [Animal] TB-500, a synthetic acetylated fragment marketed as a thymosin-beta-4 analogue, is extended by community pages to the mouse thymosin-beta-4 data, but there is no controlled human evidence that it grows hair — it remains investigational and unapproved. [Animal][Hypothesis] BPC-157 is discussed for scalp "blood flow" and inflammation via its angiogenic/wound-healing effects, which are themselves mainly animal-level, and there is no hair-loss study of any kind for it, so its use for hair is purely hypothetical extrapolation rather than evidence. [Animal][Hypothesis] For any of these, a proper diagnosis and a licensed clinician remain the right first step, not a research peptide.