Hydroquinone (prescription)

What is hydroquinone and what does it do?

Hydroquinone inhibits tyrosinase, the enzyme that drives melanin production, and is also toxic to overactive melanocytes, reducing pigment production more strongly than most cosmetic brighteners. It is used medically for melasma, post-inflammatory hyperpigmentation and sun spots, sometimes in triple-combination creams with a retinoid and a mild corticosteroid. Because of its strength, it is normally used for defined periods with breaks, rather than continuously, and under review by a doctor. It lightens excess pigment over weeks to months but does not prevent recurrence, so sun protection and maintenance with gentler actives follow. This entry is educational; strength and duration are decided by a doctor. [1]

What does the evidence show?

Hydroquinone has decades of clinical use and many trials in melasma and hyperpigmentation, and it serves as the comparator against which many newer agents are tested. Reviews support its efficacy while highlighting safety concerns with prolonged or unsupervised use. A systematic review of exogenous ochronosis links this blue-black discolouration mainly to long-term use, including of products bought without supervision, which is why medical review matters.

Who should avoid hydroquinone?

It should not be used without medical supervision, during pregnancy or breastfeeding unless a doctor advises, or on broken or inflamed skin. Prolonged use can cause exogenous ochronosis, a blue-grey darkening that is difficult to reverse, and irritation can trigger rebound pigmentation in darker skin. People with sensitive skin may develop contact dermatitis.

Is hydroquinone available in Singapore?

Hydroquinone is not permitted in cosmetic products in Singapore and is controlled as a prescription medicine supplied through a doctor. The Health Sciences Authority has repeatedly warned about unregistered lightening creams, often sold online, found to contain hydroquinone or mercury. Use only products obtained through a doctor or legitimate pharmacy.

If a dark patch, breakout or irritation is not responding to what you are using, the next step is a diagnosis rather than another product. See the Skin A–Z library for related ingredients.