Phosphatidylcholine

Phosphatidylcholine is a skin-identical phospholipid used in liposomes/emulsions and barrier-support formulas, typically at low single-digit percentages, and is generally well tolerated in sensitive and compromised skin. Clinical experience and patch-testing data suggest a low rate of irritation, but rare reactions can occur due to source impurities (e.g., soy/egg derivatives) or oxidation products in poorly stabilized formulas. Given its overall biocompatibility yet non-zero risk in highly reactive patients, it fits a very gentle score rather than inert. Safety Notes: In mass-market moisturizers, serums, and cleansers, phosphatidylcholine is most often used as a minor emulsifier/liposome component or skin-conditioning phospholipid at very low levels (typically around 0.01–0.3%), so 0.01% captures the low end seen in INCI-listed phospholipid blends. Higher-strength consumer products marketed as phospholipid/liposome delivery systems, barrier-repair concentrates, or “lecithin/phosphatidylcholine” boosters commonly use ~1–3% active phosphatidylcholine, with some specialty leave-on formulations reaching about 5% before texture, odor, and oxidative stability constraints become limiting. Rinse-off products tend to sit at the lower end because the benefit is primarily formulation-aiding, whereas leave-on lipid concentrates and liposomal serums account for the upper end.