Once the hair follicle is damaged or necrotic, there are no medications or treatments available to regrow it. Common causes of hair loss with no growth for a period of time include androgenetic alopecia, baldness and inflammatory alopecia. In some cases, hair regrowth occurs after the causative factor is removed, and a visit to the dermatologist is required to determine the type of hair loss. If the hair follicles are completely damaged, the appearance can be improved by hair transplantation. Hair follicle units, including the tissue surrounding the follicles, are removed from the hairy areas of the body and planted into the skin where hair is scarce, just like planting a tree. As long as there is good blood circulation in the recipient area, the hairs can usually survive and continue to grow. If hair loss occurs, it is recommended to consult a dermatologist in order to clarify the cause of the disease, under the guidance of the doctor to treat the symptoms, and do not use drugs on their own.