Hair loss caused solely by staying up late without damaging the hair follicles can usually grow back; if the hair follicles are affected due to frequent staying up late, the hair cannot grow. Hair follicles are located in the dermis and subcutaneous tissues, is the skin’s accessory organs, the main role is to nourish the hair, is the necessary factors for hair growth. If the hair loss is caused by simply staying up late, it will not damage the hair follicles, so the hair can grow back later. But if you stay up late for a long time, resulting in metabolic disorders, and then make the skin worse, will lead to part of the hair follicle atrophy or blockage, so it will inhibit hair growth, so try not to stay up late, after staying up late, but also to supplement the nutrients in a timely manner, try to minimize the damage to the organism by staying up late.