8397fa35_ening_ingredients___WHITERskin__2
[0] Hydroquinone [1] An industrial chemical [3] One of the most effective inhibitors of melanogenesis in vitro and in vivo. Evidence of improvement is usually observed at 4-6 weeks. Tretinoin has been used to enhance the efficacy of hydroquinone. [4] Mostly safe, but risks exist. Exogenous ochronosis has been observed in black patients who have used high concentrations of hydroquinone for many years. Thus, hydroquinone should be discontinued if no improvement occurs within 4-6 months. [2] 
Inhibits DNA synthesis and mitochondrial enzymes, has direct cytotoxic effects toward melanocytes. Also competes for tyrosine oxidation in active melanocytes.
List of commercial skin lightening / skin whitening ingredients | WHITERskin
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