What causes a lot of hair loss?

A large number of hair loss reasons are: 1. Scalp damage factors: perm hair or ringworm will cause scalp damage, resulting in a large number of hair loss. 2. Drug factors: such as high blood pressure, antidepressants and other drugs, can cause a large number of hair loss. 3. After childbirth, surgery, chemotherapy, etc. will also cause a large number of hair loss. 4. Hormone factors: close to menopause due to hormonal changes, will cause a large number of hair loss. 5. Thyroid factors: Thyroid activity is not stable, it may cause thinning of the scalp, resulting in a large number of hair loss, at this time can supplement thyroid agent to make hair return to normal.