The red onion (Allium cepa L.) have a skin that contained active compounds such as flavonoids, steroids, and phenolics that have the potential as antioxidants, one of which can be used as a hair growth stimulant. This study aimed to optimize the use of gelling agents in hair serum formulations of red onion peel extract (Allium cepa L.) as a hair growth stimulant. The formula optimization was de…