What it is
A phenolic aromatic diol used as a skin-lightening agent.
What it does
Inhibits melanin synthesis to fade hyperpigmentation, dark spots, and melasma.
Why it’s a concern
Banned in cosmetics in the EU since 2001 (allowed only in professional hair dye and nail products). The US FDA issued warning letters in 2022 against OTC skin-lightening products containing hydroquinone due to reports of exogenous ochronosis (paradoxical permanent darkening). Classified by NTP as reasonably anticipated to be a human carcinogen.
Also known as
1,4-dihydroxybenzenebenzene-1,4-diol
CAS numbers
123-31-9
Commonly found in
skin-lightening creams
Safer alternatives
- vitamin C (L-ascorbic acid)
- niacinamide
- azelaic acid
- kojic acid at low levels
Sources
- NTP 15th Report on Carcinogens
- FDA Import Alert 66-41