(114) Exploring Vitamin D as a Modifiable Factor in Female Sexual Dysfunction: A Systematic Review

Abstract Introduction Female sexual dysfunctions (FSD), including dyspareunia, vaginismus, and hypoactive sexual desire disorder, are multi-dimensional medical issues that significantly affect quality-of-life for women of all ages. Approximately 40% of sexually active females report experiencing FSD (1). Emerging evidence suggests a potential link between vitamin D, a precursor to sex hormones, and female sexual functioning, but its effects remain unclear (2–4). The therapeutic role of vitamin D supplementation for FSD, especially among women with vitamin D deficiency, is understudied. Objective To systematically review and synthesize evidence regarding the efficacy of vitamin D supplementation as a treatment option for sexual dysfunction in women. Methods A systematic review was conducted following PRISMA guidelines. Databases searched included Scopus (n = 72), PubMed (n = 25), and Web of Science (n = 20), yielding 117 records. After removal of duplicates (n = 32) and screening (n = 69), 13 studies met inclusion criteria. Eligible studies evaluated vitamin D status in women with FSD or tested vitamin D supplementation and reported sexual function outcomes. Study quality and design were considered in the synthesis. Results Thirteen studies met inclusion criteria: cross-sectional, case–control, prospective cohort, randomized controlled trials, and one meta-analysis. All were published in 2016 or later and spanned diverse populations, including premenopausal and postmenopausal women, and women with polycystic ovary syndrome (PCOS), primary infertility, euthyroid Hashimoto’s thyroiditis, or multiple sclerosis. Nine studies originated from Middle Eastern countries. Sample sizes ranged from 40 to 303 participants. Eight studies were interventional and five observational. Seven of the eight interventional trials reported improved Female Sexual Function Index (FSFI) scores following vitamin D supplementation, regardless of route (oral, intramuscular, or vaginal), with benefits generally more pronounced among women who were vitamin D–deficient at baseline. Among six interventional trials measuring serum vitamin D, three found lower levels associated with sexual dysfunction. All five observational studies reported significant associations between lower serum 25-hydroxyvitamin D and worse sexual functioning. Several studies also identified concurrent depressive symptoms, which appeared to partially mediate improvements in sexual function. Vitamin D interventions ranged from 600 IU/day to 50 000 IU/week orally and up to 300 000 IU intramuscularly, with treatment durations of 8 weeks to 6 months. One postmenopausal RCT evaluated a vaginal suppository containing 1000 IU of vitamin D. Effect sizes varied, reflecting heterogeneity in study populations, dosing regimens, treatment duration, and control conditions. Conclusions Across diverse clinical populations, vitamin D deficiency is consistently associated with worse sexual functioning, supported by all observational studies and several interventional trials. Most intervention studies-across oral, intramuscular, and vaginal routes-demonstrated improvements in FSFI scores, particularly among vitamin D–deficient women. Benefits were also observed in women with PCOS, multiple sclerosis, and Hashimoto’s thyroiditis, suggesting potential relevance across endocrine and inflammatory conditions. Mood improvements frequently accompanied sexual function gains and may partially mediate these effects. However, heterogeneity, small sample sizes, and geographic clustering limit interpretation. Further rigorously designed randomized trials are needed to define optimal dosing, treatment duration, and the populations most likely to benefit from vitamin D supplementation for FSD. Disclosure No.