Peptides, explained

Small proteins that act as messengers for firmer-looking skin. A gentle option after 40, with some good evidence for the best-known types.

Promising evidence

What they do

Peptides are short chains of amino acids, the building blocks of protein. Some act as “messengers” that may encourage skin to make more collagen. Others help carry minerals such as copper, or claim to relax expression lines.

Why they suit skin over 40

Collagen falls with age and after menopause, so skin looks less firm. Peptides are very gentle, so they suit sensitive skin and can be used alongside retinoids, morning and night.

The main types

Signal peptides

Such as palmitoyl pentapeptide-4 (Matrixyl). The best-researched type for fine lines.

Copper peptides

GHK-Cu. Popular for repair and firmness, with mostly lab and small human studies.

“Botox-like” peptides

Such as acetyl hexapeptide-8 (Argireline). Claimed to soften expression lines, but evidence is limited and they don’t work like injections.

How to use them

Morning or night, in a serum or moisturiser.
Fine to use with retinoids and niacinamide. Use copper peptides separately from strong acids and vitamin C.
Give them at least 12 weeks.

What the research shows

In a 12-week, double-blind, split-face study, 93 women aged 35 to 55 used a moisturiser with a tiny amount of palmitoyl pentapeptide on one side and the same moisturiser without it on the other. The peptide side showed a significant reduction in wrinkles and fine lines, and the cream was well tolerated. The study was funded by a skincare company.

Robinson and colleagues, International Journal of Cosmetic Science, 2005 [1]

Our take: peptides are a gentle, well-tolerated way to support firmness, especially if your skin can’t handle much retinoid. The effect is modest, so think of them as a helpful extra rather than a replacement for retinal and sunscreen.

Good to know

Do peptides work as well as retinol?

No. Retinoids have far more evidence. Peptides are a gentler extra that can be used alongside them.

Are peptides safe in pregnancy?

Most cosmetic peptides are considered gentle, but check with your GP or midwife if you’re unsure.

Do “Botox in a jar” peptides work?

Not like injections. Evidence for expression-line peptides is limited.

Sources

Robinson LR et al. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci. 2005;27(3):155-60.

This page is general information, not medical advice. Last updated 30 October 2026.