The possible causes of curly hair and uneven thickness include genetic factors, malnutrition, and damaged hair. 1. Genetic factors: If the hair is curved and uneven in thickness since childhood, and one or both of the patient’s parents also have such a situation, then it may be caused by genetic factors of such hair performance, this situation is a normal physiological phenomenon, without special treatment and excessive worry. 2. Malnutrition: Normal hair growth depends on adequate nutritional support of the hair follicles, when the patient has long-term picky eating, partiality and other bad habits, will lead to malnutrition of the patient’s body, which causes the scalp follicles do not get enough nutrient supply, so that the normal growth of hair is significantly affected by the phenomenon of hair curved and uneven thickness. 3. Hair damage: If the patient has often permed, bleached, dyed hair and other bad habits, in the long run will cause damage to the hair quality, which in turn causes hair curved, uneven thickness, hair soft, serious hair loss and other phenomena, so if there is a history of excessive dyeing and ironing, hair curved and uneven thickness may be caused by hair damage. A variety of reasons can lead to uneven hair curvature and thickness, if accompanied by other uncomfortable symptoms, we recommend that you consult a doctor in a timely manner to avoid delays in treatment.