Our men's black hair soap contains butanediol, citric acid and glycerin. It helps to restore natural hair color, reactivate hair color, and prevent hair from turning gray. Its application is simple: wet the area you want to use the soap sleeve, massage the soap sleeve into your hair or beard until it bubbles, wait 5 minutes and rinse off with warm water. After use, it eliminates the waste accumulation in the hair follicle, dregs the head microcirculation, repairs and supplements a large amount of melanin in the hair follicle, repairs the function of the hair follicle, nourishes the hair follicle, strengthens the hair root, accelerates the supply of melanin, and the hair becomes darker and darker.