Unveiling tyrosinase inhibitors: current challenges and future directions in hyperpigmentation therapy

An ideal topical depigmenting agent acts quickly, and it selectively targets the melanocytes with appreciable clinical efficacy and tolerability. Traditionally, tyrosinase inhibitors ( Tyri ) such as kojic acid, hydroquinone and arbutin have been used both as treatment agents and reference molecules for evaluating new depigmenting agents. Amongst thousands of depigmenting molecules, only few have been successfully incorporated into topical depigmenting formulations but that too with limited clinical efficacy. To understand the paradox between in vivo and in vitro efficacy of available agents, this article focusses on the testing systems for depigmenting molecules, accepted mechanism of actions, and their lesser-known effects contributing to efficacy/side effects.