The reason why the crescent on the fingernail is getting less and less may be related to age aging, nutrient deficiency, disease factors and other conditions. 1. Ageing: With the gradual increase of age, the metabolic rate in the body will gradually decline, and the phenomenon of decreasing crescent teeth may occur. 2. Lack of nutrients: If the patient has the habit of picky eating and partiality, it will lead to insufficient intake of nutrients, and due to the lack of various nutrients, it will be reflected in the nails, resulting in smaller and smaller crescents on the nails. 3. Disease factors: hypothyroidism patients due to abnormal secretion of thyroid hormone, will make the metabolism slower, the phenomenon of more and more less nourishment. Tumors belong to the consumptive disease, will also appear this symptom. There are many other reasons why the crescent moon on the fingernail is getting less and less, so it is recommended to go to the hospital for a systematic examination and a clear diagnosis.