Arbutin, also known as alpha-arbutin, is a glycosylated hydroquinone that can be extracted from the bearberry plant, as well as many other medicinal plants. Additionally, very small amounts of arbutin are found in wheat, pear skins, and some other foods. Arbutin can also be synthetically produced. Research indicates that the synthetic version of this ingredient, known as deoxyarbutin, is more effective than the natural derivative.
In cosmetics and personal care products, arbutin functions as a skin-lightening agent. After topical application, arbutin works by slowly releasing hydroquinone through hydrolysis. Hydroquinone produces reversible lightening of the skin by inhibiting melanocytes production of melanin (the pigment that gives skin color). Specifically, inhibition of the enzymatic conversion of tyrosine to DOPA (dihydroxyphenylalanine) results in the desired reduction of pigment. Ultimately, this decreases the appearance of dark spots on the skin and helps to even out skin tone. Arbutin is said to be less irritating than hydroquinone when used in similar concentrations. It also is reported to cause less photosensitivity (sensitivity to sunlight).