The strongest topical depigmenting agent. Inhibits tyrosinase and exerts cytotoxic effects on melanocytes. Prescription-only in many countries.
Topical application
AProven efficacy. Two or more independent RCTs with instrumental endpoints.
Meta-analyses confirm superiority over other depigmenting agents for melasma and post-inflammatory hyperpigmentation. Kligman's triple combination (hydroquinone + tretinoin + corticosteroid) is the gold standard for melasma treatment.
2–4% (prescription in most countries)
Hydroquinone is the strongest topical depigmenting agent in dermatology, used since the 1960s. Produced synthetically. Mechanism. Competitively inhibits tyrosinase – the key enzyme of melanin synthesis. Also cytotoxic to melanocytes: oxidizes to benzoquinone, which damages melanocyte membranes and mitochondria. Reduces melanin synthesis and the number of active melanocytes in the treated area. Where applied. Pharmaceutical 2-4%, in specialized compounding – up to 10%. Standard of care for melasma, post-inflammatory hyperpigmentation, lentigines. Often in the Kligman formula (hydroquinone 4% + tretinoin 0.05% + dexamethasone 0.01%) for severe melasma. In Spain – prescription only (Pranagen, Crema Despigmentante, Kligman formula via compounding pharmacies). In the US 2% forms were OTC until 2020, then the FDA removed them from OTC over ochronosis risk and safety concerns. Evidence base. Numerous RCTs since the 1970s confirmed efficacy in melasma (Ennes 2000, Espinal-Perez 2004 meta-analysis), MASI-score reduction 30-50% over 8-12 weeks. Outperforms most alternatives (azelaic acid, kojic acid, arbutin). Combination with tretinoin and steroid yields a higher effect. Controversy and ochronosis. Long-term use (>6-12 months) of high concentrations (>4%) causes exogenous ochronosis – gray-blue skin discoloration from homogentisic acid accumulation in the dermis. More common in darker skin. Cases are rare but irreversible. EU SCCS rates hydroquinone as Cat. 2 carcinogen for systemic use, but topical dermatological concentrations are not banned (prescription). In cosmetics EU Regulation 1223/2009 permits hydroquinone only in hair dyes ≤0.3% and artificial nails ≤0.02% – banned in skin creams. Safety. Irritation, erythema, peeling – frequent. Persistent hypo- or hyperpigmentation with improper use. Courses of 3-6 months with breaks are recommended. Pregnancy – contraindicated (FDA category C). 4-6% systemic absorption is described in pregnant patients. Lactation – contraindicated. Alternatives: tranexamic acid (topical and oral), azelaic acid, cysteamine.
Irritation potential
MediumThe Evigrade extension adds an evidence panel to Wildberries, Goldapple, Letu, iHerb, Sephora and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
Hydroquinone is not recommended during pregnancy. Consider an alternative from the same category.
Hydroquinone suits: normal, combination, oily. Use with caution in: sensitive, dry.
Hydroquinone has moderate irritation potential. Sensitive skin may show a transient reaction that usually settles with adaptation.
The strongest topical depigmenting agent.
The INCI name is Hydroquinone. It may also appear as: Benzene-1,4-Diol.
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Allergen risk
ModeratePregnancy
AvoidFor sensitive skin
Prolonged use (>6 months) without breaks can cause ochronosis – irreversible skin darkening. Used in 3–4 month cycles with rest periods.
Suitable for
Use with caution
2–4% (prescription in most countries)