Abstract
INTRODUCTION: Hyperpigmentation disorders and skin tone unevenness are a very frequent concern worldwide, especially in China; 2-mercaptonicotinoyl glycine (2-MNG, Melasyl(®)) is an innovative anti-pigmentation ingredient which binds with melanin precursors, being an alternative to tyrosinase inhibitors. Our goal was to evaluate the effects of a 2-MNG-containing serum on improving facial skin tone evenness and hyperpigmentation. METHODS: Two clinical studies were conducted in China. Clinical study 1, a randomised controlled intra-individual study, included 32 healthy individuals (individual typology angle, ITA° value within 20-41° at test back area), using a ultraviolet (UV)-induced pigmentation model. Three areas were selected and treated with either the tested serum, a positive control, or a negative control. Skin pigmentation was assessed over 4 weeks of product use, comparing the results of treated areas with the negative control. Clinical study 2, an open label study, included 42 healthy female individuals presenting at least one dark spot on their face, treated during the 56 days with the tested serum twice a day. Skin colour and melanin index were assessed over time including 7 days after discontinuation. Individual typology angle, ITA°, is a parameter for characterising human skin colour by measuring skin L*a*b* colour-space data with a skin colorimeter or a reflectance spectrophotometer. Melanin index, MI, is a parameter for characterising skin melanin content by measuring the absorption of specific wavelengths at the skin surface. RESULTS: The 2-MNG-containing serum can significantly improve ITA° value, MI and visual skin colour score. It also significantly improves skin brightness and reduces melanin content in facial skin and dark spots. Additionally, it offers moisturising benefits, helps improve the appearance of wrinkles and shows good tolerance. CONCLUSIONS: The 2-MNG-containing serum reduces melanin content in the skin and leads to significant improvements on dark spots and skin brightening. It also has good tolerance and is suitable for sensitive skin.