Hair natural curls are mostly determined by the influence of congenital genes. 1, congenital factors: the vast majority of hair curls are controlled by genes, which are expressed at birth in the form of curly hair. According to the obvious degree of gene expression, the degree of hair curling is not the same, the more obvious gene expression, the more curly hair. 2ćAcquired factors: hair curls are less affected by acquired factors, but they are not completely unaffected, such as the nutritional status of a person. If a person lacks nutrition for a long time, it may lead to dry hair, showing curly hair, but this situation does not belong to the category of natural curls. Once the nutritional supply is restored to a person who has been chronically deprived of nutrients, the original curly hair will return to normal.