A hormonal imbalance can also manifest itself in the hair and body hair. As it happens, an increase in testosterone can cause excessive hair growth, and it can be a symptom of PCOS or menopause, but not only. Conversely, a drop in estrogen can cause slower hair growth or hair loss. Hypothyroidism and hyperthyroidism can also cause hair loss.
However, “it can be very complex to understand,” says Dr. Batur. “You might assume that hair loss is hormonal, but it could be related to high or low thyroid, low estrogen, high testosterone, or something else, like vitamin deficiency or lifestyle stressors.”