What it is
Acetyl tetrapeptide-3 is a short synthetic peptide consisting of four amino acids with an acetyl group on the terminus to improve stability. It is included in skincare for its skin-conditioning role and is commonly paired with other peptides in serums and treatments. In sunscreens it appears as a supporting conditioning ingredient rather than for any sun-protective function.
Safety & warnings
Short cosmetic peptides such as acetyl tetrapeptide-3 are typically used at very low concentrations and are generally well tolerated, with a low expected potential for irritation or sensitization. It is not a recognized fragrance allergen or a comedogenic oil.
Origin & sourcing
Synthetic; manufactured by solid-phase or solution peptide synthesis and then acetylated.
Questions everyone asks
What is acetyl tetrapeptide-3?
It is a synthetic four-amino-acid peptide, modified with an acetyl group for stability, used as a skin-conditioning ingredient in skincare.
Does it provide sun protection?
No. It is a conditioning peptide; any sun protection in a product comes from its UV filters, not from this ingredient.