头发的自然光泽来自它自身的护发素：油脂，它含有蜡和脂肪，还含有抗感染的自然抗菌剂。油脂含量过多会导致油性发质，相反，油脂含量过少则会导致干性发质。

Hair’s natural shine is supplied by its own conditioner, sebum, an oil composed of waxes and fats and also containing a natural antiseptic that helps fight infection. Too much sebum results in greasy hair and conversely, too little sebum makes dry hair.