Noun
A white crystalline substance, C6H4(OH)2, obtained by the reduction of quinone. It is a diacid phenol, resembling, and metameric with, pyrocatechin and resorcin. Called also dihydroxy benzene.
Source: Webster's dictionaryDespite the controversy, it's abundantly clear is that hydroquinone is a well-researched ingredient, incredibly effective for its intended purpose, and that no other skin lightening ingredient compares to its effectiveness. Source: Internet
Besides this, hydroquinone has been linked to the development of increased exposure to UVA and UVB radiation. Source: Internet
Hydroquinone-induced ochronosis is a permanent skin discoloration that is thought to result from use of hydroquinone concentrations above 4%. Source: Internet
It is suitable for those who want long-term lightening without the risks that come with hydroquinone. Source: Internet
Once the hydroquinone has oxidized, it is no longer active and should be discarded. Source: Internet
In particular, over dryness (sometimes taking the form of dry, scaly patches), and hyperpigmentation, were tolerated much better by individuals who had previously used hydroquinone or tretinoin. Source: Internet