Normal nails are light pink in color with luster. If the nails are dull, it may be caused by manicure, malnutrition, fungal infection and other factors. 1. Manicure: When doing manicure, you will usually grind the surface of your nails, resulting in dull nails. There is no need to worry too much about this condition and no treatment is needed, just avoid grinding the nails in the future. 2. Nutritional deficiencies: due to the lack of protein, amino acids, certain vitamins and trace elements, the nails do not get enough nutrition, so the nails will appear dull and lack of light. 3. Fungal infection: If the nails are dull and accompanied by thickening, brittleness and grayish color, there may be fungal infections, and it is recommended to seek medical treatment. It should be noted that dull nails may also be related to chronic wasting disease, so, after excluding the cause of dull nails caused by manicure, you should consult a doctor in time to clarify the cause of the disease, and under the guidance of the doctor on the cause of the treatment.