The crescent of the nail is the nail matrix, which is the starting part of nail growth. Nails without crescent may be related to nutritional imbalance, etc., may also be related to certain diseases, such as hypothyroidism, anemia, etc., as follows: 1. Nutritional imbalance: If partiality or picky eating leads to nutritional imbalance, so that the body lacks certain microelements, etc., the nails will be malnourished, and there is no crescent state. 2. Hypothyroidism: this disease is a disease of low metabolism of the body due to the reduction of synthesis and secretion of thyroid hormones or the insufficiency of their physiological effects. Common symptoms are pallor, drowsiness, etc., and there may be no crescent moon in the nails. 3. Anemia: Anemia patients with initial dizziness, fatigue, drowsiness, the most common and prominent clinical manifestation of the disease is pallor. When anemia is severe, there may be no crescent in the nail. In addition, nails without crescent is also seen in normal phenomenon, some people born without, or crescent is not obvious. If the patient has no obvious discomfort symptoms, there is usually no need to worry.