What is Hydroquinone? And Why is it controversial? , The gold standard for treating these darker patches was a topical skin lightening ingredient called hydroquinone, which works by reducing the Many so called whitening pills contain glutathione, hydroquinone, or even unregulated blends, but did you know the FDA has never approved these for skin lightening? High doses may harm your liver, Hydroquinone and its analogues in dermatology a : Journal of Cosmetic Dermatology Hypothesis: Phenol and hydroquinone derived mainly from diet and gastrointestinal flora activity are causal factors in leukemia Leukemia