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

Vitamin D and Reduced C-Reactive Protein Levels

Research synthesisModerate evidenceModerate effect9 studies · 5 beneficial · 4 neutral · 0 harmful

Across 9 studies, 5 reported beneficial moderate-sized effects on reducing C-reactive protein levels, while 4 found no significant effect. The evidence suggests a moderate effect size in clinical populations, with effects typically observed over approximately 16 weeks (median study duration 112 days).

Caveats: Effect was not consistent across all studies; 4 of 9 found no significant reduction in CRP. Most beneficial studies were in populations with specific clinical conditions (e.g., COPD, diabetes, obesity) or with vitamin D deficiency; benefit may not generalize to healthy individuals with sufficient vitamin D levels. Many studies did not report dose or form, limiting dose-response conclusions.

Generated Jul 15, 2026
Doses used in studies
  • IU/day: 1,000 (median 1,000, IQR 1,000–1,000) — 2 studies
Time to effect
Median: 3.7 months · IQR 2.8 months–4.9 months · Range 8 weeks–6 months — Reported in 3 of 9 studies
Safety in these studies
9 of 9 papers
Back to top