It may be normal for some young people to have no lunulae on their fingers, but some may be abnormal. Most people have white, half-moon shaped curved circles at the back of their nails, with a distinct line between them and the light red nails in front. Usually the crescent changes with physical changes. If a young person does not have a crescent finger, it may be a normal physiological phenomenon, because some people may be born without a crescent, generally as long as there is no other physical discomfort, then there is no need to worry too much. In addition, if the recent work pressure, stay up late, overworked, etc., may also lead to the disappearance of finger nail crescent, can be improved by adjusting diet and lifestyle habits, such as eating more food rich in protein and vitamins, such as milk, soy products, spinach, bananas, apples, etc., and to avoid staying up late, to do appropriate exercise, etc. In addition, there may be other abnormalities in the body, such as the lack of crescent fingers of young people may be caused by malnutrition, lack of vitamins or trace elements, such as calcium deficiency, or because of poor blood circulation, slow metabolism, etc., resulting in the accumulation of heat and toxicity in the body. In addition, if a young person’s crescent finger suddenly disappears later in life, it may be caused by endocrine disorders such as abnormal thyroid function. In this case, the body may be accompanied by other abnormalities, it is recommended that young people go to the hospital in a timely manner, laboratory tests, hormones, etc., to clarify the cause and then treat the cause.