Hair loss in a 20 year old girl cannot be treated by a general diet. Also regardless of any age. A small amount of hair loss in a 20 year old girl is a normal physiological cause that requires no special treatment. However, frequent or sudden massive hair loss may be caused by endocrine disorders, baldness or infectious alopecia, etc. It can be improved by taking diazepam orally, applying minoxidil externally, and taking glucocorticosteroids orally, externally, or injecting them as prescribed by the doctor. Endocrine disorders: including hypothyroidism, androgenetic alopecia, etc. Hypothyroidism patients need to use thyroxine to treat the primary disease, and androgenetic alopecia can be externally applied Minoxidil, which can effectively inhibit and improve the condition. Hair loss caused by baldness is a symptom under the influence of neuropsychiatric factors, which can be treated by oral, topical or local injection of glucocorticosteroids such as prednisone to improve the symptoms of hair loss. Sedatives such as diazepam can be given to patients with nervousness, anxiety and insomnia for relief. Infectious hair loss: mainly caused by fungal, viral or parasitic infections, such as ringworm, etc., can be shampooed with ketoconazole shampoo, or the use of itraconazole, terbinafine and other drugs for antibacterial treatment. In addition to the factors that cause hair loss such as lack of sleep, insufficient nutritional intake, etc., it is recommended that the patient usually also pay attention to rest, adjust the mentality, balanced nutritional diet, and develop good living habits. Hair loss should be timely medical treatment, clear diagnosis and standardized treatment in accordance with the doctor’s instructions. Note that the above drugs need to be used under the guidance of a doctor, not blindly used on their own.