The main reasons for more gray hair after chemotherapy include malnutrition, side effects caused by chemotherapy drugs, and lack of exercise. 1. Malnutrition: most people will have different degrees of gastrointestinal reactions after chemotherapy, such as nausea, vomiting, loss of appetite, chemotherapy itself has a great consumption to the body, and after chemotherapy, they cannot replenish the nutrients needed by the body in time, so they will suffer from malnutrition. 2. Side effects of chemotherapy: chemotherapy drugs not only kill cancer cells, but also kill normal cells of the body, hair will stop growing or even fall off during the treatment period. After the treatment is finished, with the gradual metabolism of chemotherapy drugs, the toxic side effects will disappear, and the regrowth of the hair will be accompanied by changes in texture and color, which may be manifested as curling or whitening. 3. Lack of exercise: chemotherapy can also lead to low immunity, often need to rest more after the end of chemotherapy, due to the lack of exercise, blood circulation will also be affected, the scalp blood supply will be reduced, melanocytes will also be abnormal, which will easily lead to an increase in gray hair. Don’t worry too much about the gray hair after chemotherapy, it may slowly improve after the disease is cured.