In different concentrations hydroquinone inhibits or prevents skin from making the enzyme responsible for triggering melanin, the chief pigment that gives skin its color (Source: Journal of Drugs in Dermatology, March 2010, pages 215-218). Over-the-counter hydroquinone products can contain 0.5% to 2% concentrations, with 2% being the most effective OTC amount. At the pharmacy, 4% concentrations of hydroquinone (and sometimes even higher) are available by prescription only. A concentration of 12% hydroquinone actually prevents the production of melanin altogether.
t-butyl hydroquinone is an antioxidant and a weak depigmenter at 1.0 and 5.0 percent but not at 0.1 percent. The CIR Expert Panel concludes this is a safe ingredient if it does not exceed 0.1 percent. Source
Natural Alternatives to Hydroquinone
Ironically, plant extracts such as Mitracarpus scaber (madder) extract, Uva ursi (bearberry) extract, Morus bombycis (mulberry), Morus alba (white mulberry), and Broussonetia papyrifera (paper mulberry) touted as being natural skin lightening agents actually break down into hydroquinone when absorbed into skin, which explains why they have a positive effect. Another natural alternative is arbutin which also, you guessed it, breaks down into hydroquinone in skin.
See also arbutin.« Back to Dictionary Home