2. Generally speaking, it is normal for normal adults to lose 50-60 hairs a day, and losing more than 100 hairs is a hair loss signal. If you lose more than 100 hairs a day for more than 2 or 3 months, you should see a doctor as soon as possible.

3. The main component of hair is keratin, which contains a variety of amino acids and dozens of trace elements. Protein's hair will turn yellow and split if he lacks iron. Without vegetable oil, vitamin A, protein and iodine, hair will be dry, dull and easily broken. When vitamin B group is deficient, seborrheic dermatitis and alopecia will occur.