Effects of gochujang formulations on menopausal symptoms and gut microbiota in postmenopausal women: an 8-week randomized, double-blind trial.

INTRODUCTION: Menopause-associated symptoms impair quality of life, and postmenopausal women increasingly seek safe, non-hormonal, diet-based interventions. Gochujang, a traditional Korean fermented food rich in isoflavone aglycones and capsaicinoids, has biological activities relevant to menopausal health but has never been tested in a randomized trial. We compared three distinct Gochujang formulations. METHODS: In this 8-week, randomized, double-blind, three-arm trial, two Gochujang formulations differing in microbial composition (high-microorganism [HTG], low-microorganism [LTG]) were compared with commercial Gochujang (CG) in 59 postmenopausal women with moderate-to-severe symptoms [Kupperman Menopausal Index (KMI) ≥15]. Change in total KMI score and change in gut microbiota were the two registered co-primary outcomes, and change in total KMI score is the primary endpoint of this report. Because all arms received active Gochujang without a placebo, the trial assessed between-formulation differences rather than efficacy. Secondary outcomes were body composition, metabolic biomarkers, and safety; gut microbiota and fecal short-chain fatty acids (SCFAs) are analyzed here as exploratory outcomes, a post hoc reclassification. RESULTS: All formulations produced significant within-group KMI reductions (HTG: -3.65, 95% CI -4.97 to -2.33; LTG: -4.10, -5.98 to -2.22; CG: -3.42, -4.34 to -2.50; all p < 0.0001), with no statistically significant between-group differences, providing no evidence of formulation-specific effects. Percent body fat decreased and fecal SCFA concentrations declined in all groups. Gut microbiota composition shifted within all three groups, but the exploratory analyses did not provide robust evidence of formulation-specific differences. No adverse events occurred. DISCUSSION: Eight-week Gochujang consumption was safe, well-tolerated, and associated with reduced menopausal symptom severity and percent body fat across all formulations. Efficacy cannot be established without a placebo control; placebo-controlled trials with endocrine and functional microbiome endpoints are warranted. CLINICAL TRIAL REGISTRATION: https://cris.nih.go.kr, identifier KCT0011085.