Copper Lysinate/Prolinate

Copper Lysinate/Prolinate is a copper-amino acid complex used in very low concentrations in skincare (typically as a skin-conditioning/anti-aging support ingredient) and is generally well-tolerated. However, copper salts and metal complexes can provoke stinging or irritant responses in compromised barriers (e.g., eczema, post-procedure) and, less commonly, metal-related hypersensitivity, so I do not classify it as exceptionally gentle. At typical use levels it presents low but non-zero irritation potential, warranting a gentle (not inert) score for sensitive-skin safety. Safety Notes: In commercial leave-on serums/creams marketed for firming or “copper peptide” benefits, Copper Lysinate/Prolinate is typically used at very low levels (around 0.01–0.05%) because it is a potent trace-metal complex and is often positioned as an active within broader anti-aging systems. Higher-strength consumer-available “copper” boosters and peptide serums commonly top out around ~0.3–0.5% before stability, color/odor, and irritation/sensory issues become limiting; rinse-off products generally sit at the low end due to short contact time. There is no specific FDA/EU maximum for this INCI, so practical formulation and tolerability constraints primarily define the observed market ceiling.