Cosmetic Neuromodulator Peptides (Argireline, Leuphasyl)

Also known as: acetyl hexapeptide-3/-8 (Argireline), pentapeptide-18 (Leuphasyl), topical 'botox-like' peptides

Dermatology

In plain English

These are peptides added to anti-aging creams that aim to soften expression lines by gently reducing muscle contraction near the skin — a topical, far weaker cosmetic echo of what injected botulinum toxin does. Small studies suggest modest reductions in fine wrinkles. They are cosmetic ingredients, not drugs, and results are subtle and depend on the product actually penetrating the skin.

The science

Argireline (acetyl hexapeptide-3/-8) mimics the N-terminus of SNAP-25 and interferes with SNARE-complex assembly needed for calcium-dependent neurotransmitter (acetylcholine/catecholamine) release, modestly reducing muscle contraction; Leuphasyl (pentapeptide-18) acts on enkephalin receptor pathways to dampen acetylcholine release, and the two are often combined. A 10% emulsion reduced wrinkle depth up to about 30% over 30 days in early work, and a randomized study in periorbital wrinkles reported significant improvement, though large molecular size limits skin penetration.

References

• Blanes-Mira C et al., a synthetic hexapeptide (Argireline) with antiwrinkle activity, Int J Cosmet Sci 2002
• Errante F et al., cosmeceutical peptides (review), Front Chem 2020