Knuckles Cleans & Clear for Black Knuckles

Primary Target: Hyperpigmentation on knuckles, knees, elbows, and toes.
Active Mechanisms: It acts primarily as a chemical exfoliator that peels away stubborn, dead skin layers to reveal lighter skin underneath.
Key Formulation Feature: The packaging specifies that it is hydroquinone-free. [1, 2, 3, 4]