Deoxyarbutin (dA) is a skin-lightening ingredient that works by blocking tyrosinase, the enzyme responsible for melanin production. It was 4x gentler on skin cells than hydroquinone (the gold standard) while being more effective at actually reducing melanin, and the effect reversed within 5 days of stopping use—meaning it doesn't permanently alter your skin.

Researchers tested deoxyarbutin in lab-grown human skin cells, on human skin grafts, and in a small clinical trial on real people. They compared it directly to hydroquinone and a control group to measure safety, effectiveness, and whether the lightening effect was temporary or permanent.

Funding not disclosed in abstract