Which peptides for skin have evidence?
Cosmetic peptides in creams and serums have the most evidence, from small controlled trials showing modest improvements in fine lines and firmness. The three best known are Matrixyl (palmitoyl pentapeptide-4), copper peptide (GHK-Cu) and Argireline (acetyl hexapeptide-3).
Skin peptides compared
| Peptide | Type | What studies show | Form |
|---|---|---|---|
| Matrixyl (palmitoyl pentapeptide-4) | Signal peptide | Reduced wrinkle depth vs a plain cream over 12 weeks | Cream, serum |
| GHK-Cu (copper peptide) | Carrier peptide | Improved firmness and fine lines in small studies | Cream, serum; injections untested |
| Argireline (acetyl hexapeptide-3) | Nerve-signal peptide | Reduced crow’s feet in small trials; absorbs poorly | Cream, serum |
| Glow peptide blend | Injected blend | No studies | Injection |
| Melanotan II | Tanning peptide | Darkens skin; linked to mole changes | Injection, nasal spray |
How do skin peptides work?
Signal peptides like Matrixyl are thought to tell skin cells to make more collagen. Carrier peptides like GHK-Cu deliver copper, which collagen-building enzymes need, while nerve-signal peptides like Argireline aim to relax the small muscles that cause expression lines.
What is a peptide serum?
A peptide serum is a light skin care product with one or more cosmetic peptides, often combined with hyaluronic acid or niacinamide. Results build slowly over 8 to 12 weeks and are modest; peptides don’t replace sunscreen or retinoids, which have stronger evidence.
Are injected skin peptides safe?
They’re much riskier than creams. Injected GHK-Cu and blends like the Glow peptide haven’t been properly tested in people, and products sold online aren’t checked for purity or sterility.
Melanotan II, sold for tanning, has been linked to new and changing moles and melanoma case reports. Injectable glutathione for skin lightening has drawn regulator warnings.
Peptides for skin side effects
Cosmetic peptides in creams rarely cause problems beyond occasional redness or irritation, usually from other ingredients. Injected peptides can cause infection, allergic reactions and effects that haven’t been studied.