After-Rinsing Hair Growth Promotion of Hinokitiol-Containing Vesicles and Emulsions

The study from 2007 examined the effects of hinokitiol (HKL)-containing vesicles and emulsions on promoting hair growth in mice. The researchers prepared two types of topical solutions and tested their ability to retain HKL on the skin after rinsing. They found that cationic vesicles had higher HKL retention compared to nonionic emulsions, likely due to ionic interactions with the skin. In vivo experiments with female C57BL6 mice, where 0.2 ml of 1 wt% HKL was applied and rinsed daily for 30 days, showed that hair growth was significantly promoted only by HKL in cationic vesicles. The study concluded that the high skin retention of HKL by cationic vesicles was key to promoting hair growth, as opposed to nonionic emulsions which did not show this effect. Octyl salicylate was identified as the oil with the highest HKL solubility at 175.6 mg/ml, suggesting its potential for use in hair growth-promoting formulations.