Have any supplements been studied for endometriosis?

Several vitamins and supplements have been studied, including vitamin D,^[1] melatonin,^[2] and vitamins E and C. Vitamin E, with or without vitamin C, seems to improve pain symptoms. Vitamin D also improves pain symptoms to a lesser extent. Both effects are small, but given their good safety profiles, these supplements are worth considering in conjunction with other medical interventions.^[3] Melatonin has limited evidence to support its use, but it might improve pain symptoms, sleep quality, and mood symptoms in people with endometriosis.^[4]