About Hydroquinone Benzenediol derivative, Depigmenting Agent. Mechanism of Action of Hydroquinone Hydroquinone decreases the formation of melanin in the skin. It inhibits tyrosinase and other melanin forming enzymes and thus decreases the formation and increases the degradation of melanosomes. Indications for Hydroquinone 1. Melasma 2. Freckles 3. Hyperpigmention 4. Lentigo