Answer: Found in both the mulberry and bearberry plants, arbutin is known not for acne care but for its ability to lighten skin discolorations. Arbutin acts by inhibiting production of tyrosinase , the enzyme that promotes melanin. In short, less tyrosinease, less melanin. Keep in mind that Arbutin converts to hydroquinone in the body, so if you wish to avoid hydroquinone, arbutin is not the lightener you want.
Arbutin does not directly deal with the forces behind acne. However, it may be useful to lighten darkening or hyperpigmentation that can develop after breakouts. While laboratory studies indicate that arbutin can reduce melanin production it is often not possible to determine how much arbutin is used in a commerical, non-prescription products. With active ingredients like zinc oxide or salicylic acid, the concentration is listed on the label. Without this information, you cannot judge how strong or how weak an arbutin product is before you buy it. With arbutin, this info is just not provided on the package. Arbutin is often called mulberry extract and the amount of this ingredient is also not stated on the label. Like most skin lightening formulations, arbutin is usually combined with other skin brighteners including Kojic acid and even hydroquinone.
Like most lightening ingredients, arbutin has to be used for at least six weeks to see a difference. Most work by inhibiting new melanin production so you need to slough off the old darkened cells before the slow down of melanin will make a visable difference. And whenyou use a lightening agent, its absolutely imperative to use an effective SPF50 sunscreen to prevent new melanin production.
And to get back to your original acne problem. You need to look for products that contain proven, measured anti-acne ingredients eg salicylic acid and benzoyl peroxide. You also want to avoid products with acne triggers such as mineral oil, shea butter, beeswax and lanolin