Hexapeptide-8

Peptides are short chains of amino acids, the building blocks of proteins. Acetyl Hexapeptide-8 is among the best known: six amino acids with an acetyl ending, assembled synthetically. That synthetic origin often draws needless suspicion — a peptide made in a laboratory is chemically identical to one made anywhere else, and for an ingredient that must be the same every time, controlled production is a guarantee rather than a compromise.

In skincare it is used for the look of fine lines. A great deal has been written about it, some of it overblown — comparisons with aesthetic procedures turn up now and then, which European rules do not permit for a cosmetic and which we do not use. What can be said: it is a hydrating, conditioning ingredient that belongs in the water phase, and its contribution is to how skin looks and how it feels to the touch.

Peptides are water-soluble and sensitive to their surroundings. They belong in light gel and serum textures at a balanced pH, not in acidic or heavily oily formulas. And like antioxidants they make sense in company: a peptide with water-binding ingredients beside it works on the smoothness of the surface together with them, not against them.

In the No3. Hydro Boost Collagel Serum, Acetyl Hexapeptide-8 is therefore joined by a hyaluronic acid matrix in several molecular sizes, Sodium PCA and the liquid mineral malachite. The serum is the third step of the ritual — a light water layer between the toner and the finishing nourishment.

Skincare uses a whole family of peptides, with names similar enough to confuse — hexapeptide, palmitoyl pentapeptide, tripeptide. For anyone reading a label, one useful rule follows: a peptide is a hydrating, conditioning ingredient and belongs in the light layer in the middle of a routine. It replaces neither cleansing nor the finishing nourishment, and on its own it will not do what a whole layered routine does.