Early or just after hair loss: at this time, the hair follicle is in a healthy state, and the hair will grow again after falling off without special treatment.
Hair loss can be clearly seen: the hairline moves backwards or the forehead retreats. At this time, the hair follicle has gradually developed from a healthy state to a atrophic state. At this point, the shrinking hair follicles can be stimulated by drugs to grow.
Large area hair loss, hair loss is more serious: at this time, the hair follicle has slowly developed from atrophy to closed necrosis. At this time, the role of drugs has been relatively small, and the hair loss area can be regenerated by hair transplantation.