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 small beneficial effects of vitamin D supplementation on fasting plasma glucose, while 1 reported neutral findings. The median study duration was 42 days (1 study). Effects were predominantly small in magnitude. The most-studied populations were clinical populations with diabetes, prediabetes, or gestational diabetes.

  • Studied populations: patients with type 2 diabetes, prediabetes, or gestational diabetes

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. One meta-analysis noted that observed glycemic effects were modest and may diminish over time. Only one study reported a specific dose (1000 IU/day) and duration (42 days), limiting the ability to generalize dose-response or long-term effects.

Generated Jun 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