BackgroundPrimary dysmenorrhea in women is a common and serious public health problem with psychological and physical effects. Painkillers have adverse effects, such as tolerance, addiction, irritation of the digestive tract, and liver and kidney damage. Electroacupuncture has been used as alternative therapy, although with no (non-anecdotal) evidence of effectiveness.ObjectiveThis study aims to provide evidence for the feasibility and efficacy of electroacupuncture in the treatment of primary dysmenorrhea. Moreover, by observing changes in serum and urine metabolites, we will evaluate the putative mechanisms mediating electroacupuncture effects in primary dysmenorrhea.MethodsThis multicenter, randomized, participant-blinded, sham-controlled clinical trial including 336 women with primary dysmenorrhea is being conducted at three hospital centers in China and consists of a 12-week treatment and a 3-month follow-up. Women will undergo electroacupuncture (n = 168) or sham acupuncture (n = 168), beginning 7 days before their menstruation, once per day, until menstruation. Each menstrual cycle equals one course of treatment, and we will evaluate a total of three courses of treatment. The primary outcome of interest is the change in visual analogue scale scores before and after treatment. The secondary outcomes include changes in the numeric rating scale, Cox Menstrual Symptom Scale, traditional Chinese medicine symptoms, the Self-Rating Anxiety Scale, Self-Rating Depression Scale, and 36-Item Short Form questionnaire scores, and a safety evaluation. Moreover, we will preliminarily investigate the metabolomics mechanism as a potential mediator of the association between electroacupuncture and primary dysmenorrhea symptomology.DiscussionWe aim to find a suitable non-medicinal alternative for primary dysmenorrhea treatment to reduce reliance on non-steroidal anti-inflammatory drugs.Trial registrationChinese Clinical Trial Registry:ChiCTR2100054234;http://www.chictr.org.cn/.