4-Butylresorcinol

Highly potent tyrosinase inhibitor with reversible dicopper coordination mechanism that generates no quinone intermediates, providing mechanistic safety advantages over hydroquinone. 2024 comparative study ranked it as the strongest tyrosinase inhibitor among six evaluated depigmenting agents; however, the same study documented concentration-dependent cell viability reduction, confirming that the 0.3% Japan quasi-drug dose represents the therapeutic ceiling. No reported cases of ochronosis or leukoderma in peer-reviewed literature. Clinical trials show only mild transient side effects. Japan quasi-drug approved since 1998. Not EU-restricted. Achieves efficacy comparable to hydroquinone at just 0.3%; optimal use requires disciplined dosing within validated range and combination with complementary mechanisms (niacinamide, TXA) rather than concentration escalation. The EU classifies 4-Butylresorcinol as "permitted". Safety rating: GOOD.

4-Butylresorcinol EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.

4-Butylresorcinol functions as: Potent competitive tyrosinase inhibitor; reversible phenolate coordination to the dicopper catalytic centre of tyrosinase without forming quinone intermediates; effective melanogenesis inhibition at low concentrations (0.3%); also inhibits TRP-1. It is classified as a Active Ingredient in our database. CAS number: 18979-61-8.

adequate The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.