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PEPTIDE READER

Peptides for skin & hair

9 peptides · T3 7 · T2 1 · T1 1

Skincare peptides are almost never tested the way medicines are tested. Six of the nine entries here rest on small, short studies, several of them run or paid for by the company selling the ingredient, and a seventh has no published study at all. A cosmetic claim does not have to prove a clinical effect before it can be printed on the box. The last two are not skincare ingredients in any ordinary sense: one is an unapproved injection sold online to darken skin without sunlight, whose entire tanning evidence is a pilot study in three men and whose reported harms have made several national regulators warn against it by name; the other is a three-amino-acid fragment sold for inflamed skin that has never been given to a person in a published study at all.

  1. Tested in people, but barely

    Acetyl hexapeptide-8

    Argireline · acetyl hexapeptide-3

    Sold in skincare for expression lines and wrinkles.

    The studies are small and short, and one independent trial finished without publishing results.

    Skincare
  2. Tested in people, but barely

    Collagen peptides (hydrolysed collagen)

    hydrolysed collagen · collagen hydrolysate

    Sold as a supplement for skin, hair, bones and joints.

    Small human trials report some skin and joint changes, but many were funded by the industry selling the products.

    Supplement
  3. Tested in people, but barely

    GHK-Cu (copper tripeptide-1)

    Copper Tripeptide-1 (INCI) · copper peptide

    Sold in skincare for wrinkles, skin repair and hair growth.

    Human studies are small, and the only blinded objective measurement found no clear benefit.

    Skincare
  4. Tested in people, but barely

    Melanotan II

    Melanotan 2 · Melanotan-2

    Sold online as a tanning injection, and separately as something that produces erections.

    Two placebo-controlled studies in 20 men found it produces erections; the tanning evidence is one pilot in three men, and the harms are single case reports.

    Gray market
  5. Tested in people, but barely

    Palmitoyl pentapeptide-4

    Matrixyl · pal-KTTKS

    Sold in anti-wrinkle skincare.

    The main human study was small and linked to the ingredient's commercial development.

    Skincare
  6. Tested in people, but barely

    Palmitoyl tetrapeptide-7

    pal-GQPR · Rigin

    Sold in skincare blends for wrinkles and irritated-looking skin.

    No peer-reviewed human study has tested this ingredient on its own.

    Skincare
  7. Tested in people, but barely

    Palmitoyl tripeptide-1

    pal-GHK · Biopeptide CL

    Sold in skincare to support collagen and soften wrinkles.

    The evidence comes from two small experiments submitted by the raw-material supplier.

    Skincare
  8. Only tested on animals

    KPV

    KPV peptide · Lys-Pro-Val

    Sold for gut inflammation, skin conditions and wound healing.

    No published study has ever given it to a person; the evidence is mouse, rat and rabbit experiments and cells in dishes.

    Gray market
  9. No real evidence at all

    Acetyl tetrapeptide-5

    Eyeseryl · Acetyl Tetrapeptide-5 (INCI)

    Sold in eye creams for puffiness and dark circles.

    No peer-reviewed clinical study of this ingredient has been published.

    Skincare