Nutritional supplements in the treatment of endometriosis-associated symptoms: a systematic review

ABSTRACT: Dietary supplements and antioxidant therapies are frequently used by women with endometriosis to improve symptoms; however, their clinical effectiveness remains unclear. This systematic review evaluated the effects of dietary supplements on pain, quality of life (QoL), fertility outcomes, and lesion progression in women with endometriosis. MEDLINE via PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials (RCTs). The eligibility criteria included women with diagnosed endometriosis receiving dietary supplements compared with placebo, no treatment, or standard care. Findings were narratively synthesized, and risk of bias was assessed using RoB 2. Twenty-four RCTs, involving 2,019 participants, were included. Pain findings were heterogeneous. Improvements across multiple pain domains were reported with nanomicellar curcumin, used either alone or as an adjunct to dienogest, selenium added to dienogest, Proscur, and garlic; vitamin and melatonin findings were mixed, while omega-3 fatty acids, conventional curcumin, and resveratrol showed no clear benefit. QoL outcomes were similarly heterogeneous: nanocurcumin plus dienogest, Proscur, and postoperative multinutrient therapy improved overall or disease-specific QoL, whereas most other interventions showed no between-group benefit. Fertility outcomes were limited to intermediate markers of reproductive success, which improved in some studies but did not lead to higher pregnancy rates. Evidence on lesion progression was limited; adjunctive nanocurcumin and selenium reduced endometrioma size, while postoperative multinutrient supplementation did not reduce recurrence. Dietary supplements may improve selected symptom-related outcomes, but effects were intervention-specific and evidence remains insufficient to support their routine use as standalone treatments. Further adequately powered trials are needed. LAY SUMMARY: Endometriosis is a condition where tissue similar to the lining of the uterus (endometrium) grows outside the uterus, which can cause severe chronic pelvic pain, limit quality of life, and lead to infertility. In addition to standard medical treatment (painkillers or hormones), many patients with endometriosis use additional supplements, such as vitamins or antioxidants, to alleviate symptoms, but it is unclear how well these approaches work. In this study, we reviewed 24 clinical trials involving 2,019 women with endometriosis to evaluate the effects of dietary supplements. Some trials reported improvements in pain and quality of life, particularly with specially formulated curcumin or selenium, alone or alongside dienogest. Studies on fertility found improvements in some fertility-related measures, but these did not lead to higher pregnancy rates. Evidence on progression was limited: some combination treatments reduced ovarian endometriosis, but supplements did not reduce recurrence after surgery. Supplements may therefore support standard treatment, but should not replace it.