Abstract
Background: Hydroquinone (HQ) is the standard induction therapy for melasma, while cysteamine (CYS) offers a non-melanocytotoxic alternative potentially suitable for long-term use. But due to paucity of real-world comparative studies between the two in India, we compared the efficacy and safety of 5% CYS versus 4% HQ in patients with facial melasma.
Methods: This randomized, open-label, single-center study enrolled 55 adults who were assigned to either CYS 5% or HQ 4% for 16 weeks with standardized photoprotection. Co-primary endpoints were percentage change in Melasma Severity Index (MSI) and modified Melasma Area and Severity Index (mMASI) at Week 16. Secondary outcomes included change in melanin index and safety assessments.
Results: Of 55 randomized patients, 30 completed the study (HQ 14, CYS 16). At Week 16, MSI and mMASI decreased significantly in both groups (HQ −64.2% and −48.4%; CYS −40.7% and −30.6%). Melanin index reduced by 22.0% and 10.6% in HQ and CYS groups respectively. Between-group differences favored HQ at Week 4 (MSI: 27.08%, p=0.004; mMASI: 18.14%, p=0.008) and Week 8 (MSI: 21.48%, p=0.024), but narrowed by Week 16 (MSI p=0.064; mMASI p=0.090). Three patients (10.7%) in HQ and four patients in CYS (14.8%) discontinued the treatment due to adverse events and 18 patients were lost to follow-up. But overall, both the treatments were well tolerated.
Conclusions: More rapid pigment lightening was achieved with HQ, while CYS showed gradual but accumulating improvement over 16 weeks. Findings support HQ as an induction option when faster onset is desired and CYS as an option for long-term therapy in melasma management.