Development and evaluation of O/W lotion containing Zingiber montanum rhizome extract for skin brightening and hydration effects

Abstract

This study aimed to develop and evaluate the properties of an oil-in-water (O/W) lotion formulation containing 0.2% Zingiber montanum (phlai) rhizome extract for its effects on skin brightening and hydration. The lotion exhibited a smooth yellow texture, a characteristic phlai odor, and a pH of 6.26. Accelerated stability testing under alternating low and high temperatures showed no phase separation, with texture and odor remaining unchanged, although the yellow color became lighter and the pH increased slightly. The evaluation of skin brightening and hydration was conducted in 20 volunteers, consisting of 3 males and 17 females aged between 21 and 22 years, over a 4 week period. Melanin Index (MI) and skin hydration (AU) were measured before and after product application. Results revealed that MI decreased significantly (−11.67; p<0.05), indicating improved skin brightness, while hydration increased significantly (+14.37; p<0.05), demonstrating the lotion’s efficacy in enhancing water retention and reducing skin dryness. A five point satisfaction assessment showed that most volunteers rated texture, absorption, non stickiness, and hydration highly, although scores for skin brightening remained moderate. In conclusion, the O/W lotion containing phlai rhizome extract has potential as a skincare product to improve hydration and skin brightness. Nevertheless, further studies with larger sample sizes are recommended to optimize the formulation and confirm the findings for greater reliability.