The darker the eyebrows grow may be related to genetic factors, dietary factors, endocrine disorders and other reasons. 1. Genetic factors: As each person’s eyebrow growth is mainly related to genes, personal constitution and so on. Some people may have darker and darker eyebrows. 2. Dietary factors: usually more nutritious, the hair follicles will take more, prompting the growth of eyebrow hair, so that the phenomenon of eyebrow hair grows darker and darker. 3. Endocrine disorders: If the secretion of androgen is strong, it may cause the growth of eyebrow hairs, and the phenomenon of eyebrow hairs getting darker and darker may also occur. If only the eyebrows grow darker and there is no other obvious discomfort, usually there is no need for special treatment. If the hyperpigmentation is more serious and even affects aesthetics, it is necessary to consult a doctor in time for examination and treatment under the doctor’s guidance.