Effect of essential oils, hydrating agents, and ethanol on hair removal efficiency of thioglycolates

Background The required time for hair removal by chemical depilatories has always been a concern and depends on different parameters including permeation into the hair shaft. Objectives In an attempt to improve this process, it was decided here to investigate the possibility of decreasing depilation time of thioglycolates, widely used depilatories, using penetration enhancers. Methods Urea, sodium dodecyl sulfate, dimethylsulfoxide (DMSO), ethanol (75 and 96%), NaCl, and peppermint and orange oils were used as penetration enhancers, and their effect on depilatory time of thioglycolates, represented as tear resistance time (TRT) of hair shaft under a constant tensile stress, was studied. The effects of temperature and hydration on TRT were also investigated. Results Results showed that ethanol (75%), DMSO, and peppermint oil (ethanolic solution) were able to significantly reduce TRT up to two times from about 6 to 3.5min. Other enhancers were not able to change TRT. Results also revealed that increase in temperature from 20 to 37 degrees C reduces TRT by about 4 times. Hydration in boiling water also reduced TRT significantly about 1.5 times. Conclusions Present results show that it is possible to reduce depilation time by penetration enhancers. Such improvement can increase users' compliance and might provide other advantages like decreased skin irritation.