There is no scientific basis for the notion that gray hair will grow more if you pull it out. As we age, the ability of hair follicles to synthesize melanin diminishes, and the hair gradually turns gray. Regardless of whether or not you pull out your hair, this process progresses steadily. 1. After pulling out a gray hair, neither black hair nor more gray hair will grow. As we age, the body ages, and the ability of the hair follicles to synthesize melanin weakens, gray hair is bound to grow more and more. There is no scientific basis for the claim that the more you pull out the more gray hair you have. 2. The causes of hair whitening are very complex, and age, living habits, mental stress, nutritional status have a close relationship, but also by genes and genetic control. In addition, suffering from certain diseases such as hyperthyroidism, chronic kidney disease, vitiligo, albinism, etc., may also lead to gray hair. After the appearance of gray hair, do not panic, need to be examined to rule out disease factors, usually pay attention to regulating the mental state, to ensure adequate sleep and balanced nutrition, if necessary, to the hospital, follow the doctor’s instructions for treatment.