4-butylresorcinol

4-Butylresorcinol (CAS 18979-61-8), also marketed as Rucinol, is a synthetic depigmentation active used in cosmetic and pharmaceutical formulations.

Where is 4-butylresorcinol used?

• Skin-brightening and hyperpigmentation correction: inhibits tyrosinase and peroxidase enzymes involved in melanin synthesis
• Premium skincare: serums, creams and spot treatments targeting melasma and age spots
• Post-inflammatory hyperpigmentation: often used at concentrations between 0.1% and 1%
• Pharmaceutical topical preparations: active ingredient in prescription and OTC depigmenting products
• Antioxidant activity supports use as a stabilizer where oxidative degradation is a concern
• Some specialty formulations incorporate it for its mild preservative-boosting effect alongside primary systems.

Good to know: Regulatory-grade purity is required for these applications to ensure safety and efficacy. High-purity grades, typically ≥98% or ≥99% by HPLC, are standard for active cosmetic ingredient supply chains.

Commercial specifications

• High-purity grades, typically ≥98% or ≥99% by HPLC
• Packaging from small quantities for R&D sampling to kilogram-scale lots for commercial batches