Efficacy and Tolerability of an Isobutylamido-thiazolyl-resorcinol Cream 0.2% for Facial Hyperpigmentation

Facial hyperpigmentation is a skin issue that occurs frequently in people with darker skin types. Studies show that the prevalence of facial hyperpigmentation is related to ethnicity and is accounted for up to 40%of the total population. The pathogenesis of facial hyperpigmentation is still unclear, but several factors seem to contribute such as ultraviolet radiation, female hormones, and genetics, which increase melanin production in the skin cells, specifically the epidermal melanocyte, and dermal melanophage. Hyperpigmentation can be embarrassing and affect the quality of life in the pertained individuals.

Tyrosinase enzyme plays a key element in melanin production which causes dark areas. In 2018, several studies have reported a new cosmetic product using Isobutylamido-thiazolyl-resorcinol (Beiersdorf AG, Hamburg, Germany) in facial hyperpigmentation. In vitro studies found that in melanocyte culture, Isobutylamido-thiazolyl-resorcinol inhibit melanin production. Studies discovered that Isobutylamido-thiazolyl-resorcinol 0.2% can reduce facial hyperpigmentation within 4 weeks. Hyperpigmentation begin to fade away within 12 weeks of daily application.

The objective is to study efficacy and tolerability of a cosmetic formulation with Isobutylamido-thiazolyl-resorcinol 0.2% compared to its vehicle in facial hyperpigmentation after 4, 8 and 12-week.

This is a randomized double-blind and vehicle-controlled study. Two hundred subjects both male and female 18 years or older with facial hyperpigmentation are recruited in the study. The study was performed at the Institute of Dermatology, Bangkok, Thailand. Subjects agree to attend monthly sessions every 4 weeks for 12 weeks.

Inclusion criteria

• Subjects are Thai adults age 18 years old and above .
• Subjects suffer from facial hyperpigmentation for at least 10 years, with or without freckles, lentigo or dark sports.
• Subjects must be able to attend monthly sessions in the period of 12 weeks session.
• Subjects must refrain from using other whitening cream such as hydroquinone, azelaic acid, kojic acid, arbutin, glycolic acid or any other creams which whiten the skin including chemical peel or whitening pills such as Tranexamic acid at least 1 month before the trial.
• Subjects must refrain from receiving both ablative and nonablative laser treatment at least 3 months before the trial.
• Subjects who can apply sun screen with UVA and UVB protection that has a minimum of SPF30 daily.

Exclusion criteria

• Subjects who have conditions such as Lichen planus pigmentosus, Pigmented contact dermatitis, Photosensitivity, Ashy dermatosis, Dermal melanosis, e.g. Nevus of Hori, Nevus of Ota, Dermal melanocyte hamartoma
• Subjects with a congenital disease which darkens skin tone, e.g. Addison's disease, Cushing's syndrome and Thyrotoxicosis
• Subjects with a congenital or serious disease with unpredictable symptoms such as Cirrhosis, cardiovascular diseases, Neurological diseases, gastrointestinal disease, Reproductive system diseases, Cancer and Psychiatric diseases.
• Subjects who take pills that might cause hyperpigmentation such as chemotherapy, Amiodarone, Chlorpromazine, Hydroxychloroquine, Gold, Birth control pills (if related to causing hyperpigmentation issue)
• Female subjects with pregnancy and breastfeeding.
• Subjects who are allergic to chemical compound in the cream such as Alcohol denat, Phenoxyethanol or fragrance.