Pal-AHK, also called Palmitoyl Tripeptide-3, is a synthetic peptide comprised of three amino acids linked to a palmitoyl fatty acid residue. It is used individually or in combination with other peptides to boost collagen synthesis in laboratory experiments examining aging and skin. Pal-AHK is thought to interact with transforming growth factor-β (TGF-β) to activate fibroblasts.