Functional hypothalamic amenorrhea (FHA) is one of the most frequent menstrual cycle disorders in women of childbearing age. The diagnosis of FHA is based on the exclusion of other causes of the absence of menstruation, including organic and anatomical disorders. This condition is reversible when the underlying causes are eliminated. The main determinant of the disorder is a combination of psychosocial and metabolic stress. Predisposing factors include low energy availability, nutritional deficiencies, excessive physical activity, lack of endometrial regeneration, sleep disorders, emotional stress, uncontrollable chronic or severe stress, and dysfunctional behavior. In response to these factors, the pulsating secretion of gonadotropin-releasing hormone (GnRH) in the hypothalamus is blocked, which leads to abnormal secretion of tropic hormones by the pituitary gland, including follicle-stimulating hormone (FSH) and luteinizing hormone (LH). As a result, estrogen production decreases and ovulation does not occur. Progesterone is also absent, since ovulation is completely blocked, and progesterone is produced as a result of luteinization of granulosa cells of the ovulating follicle. The entire monthly cycle is disregulated and eventually completely ceases. It is noteworthy that changes in the menstrual cycle are the last sign of disorder. Symptoms such as lack of ovulation and an abbreviated luteal phase should be of primary concern. These manifestations exist despite the seemingly normal monthly discharge of bloody discharge from the uterus. Without the use of specialized tests, these violations often go unnoticed. In other observations, more pronounced signals include irregular menstruation, elongated cycles, and spotting called “oligopolymenoresis.” The last stage is the complete absence of menstruation.