Effect of Vitamin D Supplementation on Sexual Function in Women With Type 2 Diabetes: Study Protocol for a Randomized, Double-Blind, Placebo Controlled Clinical Trial Publisher

Summary: Can vitamin D improve sexual health in women with diabetes? A registered trial will test supplementation, but its protocol reports no treatment results yet. #WomensHealth #Diabetes

Shakouri Joubani F ; Kianpour M ; Siavash M
Source: Contemporary Clinical Trials Communications Published:2026

Abstract

Background Female sexual dysfunction (FSD) is a common and often overlooked complication of type 2 diabetes, adversely affecting quality of life and marital satisfaction. It involves vascular, neurological, hormonal, and psychological mechanisms. Vitamin D deficiency, prevalent among individuals with type 2 diabetes, is associated with metabolic disturbances, endothelial dysfunction, and may contribute to impaired sexual function. Although some studies in healthy women with low vitamin D levels suggest benefit, evidence on its effect in women with type 2 diabetes is limited. Methods This randomized, double-blind, placebo-controlled clinical trial investigates whether weekly vitamin D supplementation improves sexual function in reproductive-age women with type 2 diabetes. One hundred eligible participants will be randomly allocated (1:1) to receive either vitamin D (50,000 IU) or placebo weekly for 12 weeks. The primary outcome is change in total Female Sexual Function Index (FSFI) score from baseline to week 13. Secondary analyses will explore relationships with glycemic control (HbA1c and fasting blood sugar), body mass index (BMI), and demographic factors. Women with severe stress, anxiety, or depression, as assessed by the Depression, Anxiety and Stress Scale (DASS-21), will be excluded. Compliance will be monitored via weekly follow-up, and analyses will follow the intention-to-treat principle using appropriate statistical tests at a significance level of 0.05. Discussion This trial will provide evidence on the effectiveness of vitamin D supplementation in improving sexual function among women with type 2 diabetes, potentially offering a safe and cost-effective approach to enhance metabolic and sexual health. Trial registration Iranian Registry of Clinical Trials, IRCT20150624022896N3 (registered 2024-02-27). Copyright © 2026. Published by Elsevier Inc.