Efficacy of Organic Selenium Supplementation on Endometrioma Regression and Pain in Women With Endometriosis: A Triple-Blind Randomized Controlled Clinical Trial.

Endometriosis is a non-malignant, estrogen-dependent chronic inflammatory disorder that affects 10-15% of women during their reproductive years. Emerging evidence highlights the undeniable role of oxidative stress in the etiopathogenesis of endometriosis. Selenium, a potent antioxidant, is vital for intracellular redox reactions. Recent research has highlighted the potential of antioxidants as therapeutic agents to mitigate oxidative stress and alleviate endometriosis symptoms. Selenium plays a key role in regulating the enzyme glutathione peroxidase (GPx). This study aimed to evaluate the therapeutic efficacy of a yeast-based organic selenium in disease progression and alleviating painful symptoms. This triple-blind randomized controlled clinical trial was executed within 66 women diagnosed with endometriosis in Tabriz, Iran. Participants were required to possess diagnostically verified endometriosis with endometrioma and a dysmenorrhea score of ≥ 16 on the Menstrual Distress Questionnaire (Moos). Using block randomization with block sizes of 4 or 6, participants were assigned (1:1 ratio) to receive either one 200-mcg capsule of organic selenium or an identical placebo along with routine treatment (2 mg of verojest (dienogest) daily for 3 months). Data were collected using socio-demographic and menstrual-obstetric questionnaires, the Moos, and the visual analogue scale (VAS) for pain. After 3 months, participants completed follow-up questionnaires and underwent ultrasonography. Statistical analyses included descriptive and inferential tests (chi-square, independent t-test, ANCOVA, and repeated-measures ANOVA). A p-value of < 0.05 was considered statistically significant. Three months after the intervention, a statistically significant reduction in endometrioma size was observed in the selenium group (from 4.82 to 3.78 cm) compared to placebo (from 4.07 to 5.31 cm) (adjusted mean difference [aMD]: -1.95 cm; 95% CI -2.6 to -1.3; Cohen's d = -0.86, large effect). Additionally, the selenium group experienced significantly greater reductions in dysmenorrhea scores (aMD -10.94; 95% CI -15.16 to -6.71; Cohen's d = -1.14, large effect), dyspareunia (aMD -3.21; 95% CI -4.34 to -2.07), dysuria (aMD -1.41; 95% CI -2.12 to -0.69), dyschezia (aMD -2.11; 95% CI -3.22 to -0.99), and non-cyclic pain (aMD -2.73; 95% CI -3.77 to -1.68) over time (at 1, 2, and 3 months post-intervention), compared to placebo. No serious or health-threatening adverse events were reported in either group. Our findings support the hypothesis that organic selenium supplementation may present a promising adjuvant therapy to reduce the size of endometriomas and alleviate various painful symptoms associated with endometriosis, including dysmenorrhea, dyspareunia, dysuria, non-cyclic pain, and dyschezia. ClinicalTrial.gov Identifier: IRCT20110606006709N26.