Skip to main content
Evidence-Based Supplement Research
Evidence-Based Supplement Research
Pillser
Search
Sign UpLog In

Vitamin D and Improved Fasting Plasma Glucose

Research synthesisLow evidenceSmall effect3 studies · 2 beneficial · 1 neutral · 0 harmful

Across 3 studies, 2 reported beneficial small-sized effects of vitamin D supplementation on improved fasting plasma glucose, while 1 reported a neutral effect. The evidence is predominantly small in magnitude, with one RCT showing a significant reduction in fasting glucose (-3.6 mg/dL vs. +1.5 mg/dL, p=0.04) in 60 women with gestational diabetes over 42 days.

  • Effective dose range: 1000 IU/day
  • Studied populations: women with gestational diabetes mellitus, patients with diabetes and prediabetes, adult patients with type 2 diabetes mellitus

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Two of the three studies were meta-analyses, one of which found no significant effect, and none provided dose or duration details, limiting comparability. Results may differ by population and baseline vitamin D status.

Generated Jul 14, 2026
Doses used in studies
  • IU/day: 1,000 (median 1,000, IQR 1,000–1,000) — 1 study
Time to effect
Median: 6 weeks · IQR 6 weeks–6 weeks · Range 6 weeks–6 weeks — Reported in 1 of 3 studies
3 of 3 papers
Back to top