Clinical Evaluation of the Human Tyrosinase Inhibitor Thiamidol (isobutylamido thiazolyl resorcinol) in Prevention of UVB-induced Hyperpigmentation
Issued Date
2025-03-01
Resource Type
eISSN
25741624
Scopus ID
2-s2.0-105002066717
Journal Title
SKIN: Journal of Cutaneous Medicine
Volume
9
Issue
2
Rights Holder(s)
SCOPUS
Bibliographic Citation
SKIN: Journal of Cutaneous Medicine Vol.9 No.2 (2025)
Suggested Citation
Vachiramon V., Kositkuljorn C., Leerunyakul K., Chanprapaph K. Clinical Evaluation of the Human Tyrosinase Inhibitor Thiamidol (isobutylamido thiazolyl resorcinol) in Prevention of UVB-induced Hyperpigmentation. SKIN: Journal of Cutaneous Medicine Vol.9 No.2 (2025). doi:10.25251/skin.10.supp.545 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/109531
Title
Clinical Evaluation of the Human Tyrosinase Inhibitor Thiamidol (isobutylamido thiazolyl resorcinol) in Prevention of UVB-induced Hyperpigmentation
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Abstract
Background: Thiamidol (isobutylamido thiazolyl resorcinol) has been identified as a potent human tyrosinase inhibitor. A formulation containing Thiamidol has recently shown promising efficacy for the treatment of some hyperpigmentation conditions. Objectives: This study aimed to evaluate the efficacy and safety of a Thiamidol-based formulation in the prevention of ultraviolet (UV)-induced hyperpigmentation. Materials and Methods: We performed a randomized, single-blinded, pilot study in healthy participants, N=30. One arm was randomly assigned to receive a Thiamidol-based formulation for three weeks. Three hyperpigmented spots were induced by UVB irradiation on both arms after 3 weeks of Thiamidol application. Outcome evaluations included measuring mean lightness index (*L) obtained by colorimeter, hyperpigmentation scores by visual analog scale (VAS), and adverse effects. Results: Both experimental sides showed no significant difference in terms of skin lightening after Thiamidol application. However, the Thiamidol-treated sides showed a statistically significant lower mean lightness index compared to control after an induction with UVB. In addition, the Thiamidol-treated sides had an earlier improvement and resumed normal skin color after 3 weeks post-UVB induction. A clinical evaluation by a blinded non-treating physician and subjects was more favorable on the Thiamidol-treated side than the control side (P <.05). No significant side effect was noted. Conclusions: Thiamidol is an effective agent in the prevention of pigmentary change from UVB irradiation and may serve as a promising agent for preventing other hyperpigmentation conditions.