Vitamin D and Reduced High-Sensitivity C-Reactive Protein Level

Research synthesisLow evidenceModerate effect4 studies · 2 beneficial · 2 neutral · 0 harmful

Across 4 studies, evidence for vitamin D reducing hs-CRP is mixed: 2 studies reported beneficial effects (one moderate, one moderate effect size) and 2 reported neutral effects (both small). Statistically significant findings were limited to 2 studies. The most-studied dose was 2,000 IU/day, and effects were observed in clinical populations over a median duration of 84 days (12 weeks).

Effective dose range: 2,000 IU/day
Studied populations: clinical populations (adults with overweight/obesity and low-grade inflammation, epilepsy patients on enzyme-inducing ASMs, postmenopausal women)

Caveats: Evidence base is small (only 4 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. The only significant beneficial finding was in a small trial (n=40), while a higher-quality neutral trial (n=76) found no improvement.

Generated Jun 11, 2026

Doses used in studies

IU/day: 200–2,000 (median 1,100, IQR 650–1,550) — 2 studies
IU/week: 40,000 (median 40,000, IQR 40,000–40,000) — 1 study

Time to effect

Median: 2.8 months · IQR 10 weeks–2.8 months · Range 8 weeks–2.8 months — Reported in 3 of 4 studies

4 of 4 papersPopulation:

Potential Modulation of Inflammation and Physical Function by Combined Probiotics, Omega-3 Supplementation and Vitamin D Supplementation in Overweight/Obese Patients with Chronic Low-Grade Inflammation: A Randomized, Placebo-Controlled Trial.
- 2023-05-10
- RCT · n = 76
- International journal of molecular sciences 24(10)
- - Lena Kopp
  - Anna Schweinlin
  - Lina Tingö
  - Ashley N Hutchinson
  - Viktoria Feit
  - Tabea Jähnichen
  - Katja Lehnert
  - Walter Vetter
  - Andreas Rings
  - Morten G Jensen
  - Robert J Brummer
  - Stephan C Bischoff
- PubMed: 37239916
- DOI: 10.3390/ijms24108567
5 Insights on
- Reduced High-Sensitivity C-Reactive Protein Level
- High evidence
- Rigorous Journal
- Clinical
hs-CRP levels did not change post-intervention, other than an unexpected slight increase observed in the treatment group.
Effect
Neutral
Effect size
Small
Significant
No
Dose
200 IU of vitamin D
Effect of vitamin D supplementation on metabolic syndrome and atherosclerosis biomarkers in epilepsy: a randomized controlled trial.
- 2026-02-27
- RCT · n = 40
- Medicinski glasnik : official publication of the Medical Association of Zenica-Doboj Canton, Bosnia and Herzegovina 23(1)
- - Sri Handayani
  - Zen Hafy
  - Fitri Octaviana
  - Zulkhair Ali
  - Nita Parisa
  - Astri Budikayanti
  - Dessy Agustini
  - Radiyati Umi Partan
- PubMed: 42047069
- DOI: 10.17392/2062-23-01
4 Insights on
- Reduced High-Sensitivity C-Reactive Protein Level
- High evidence
- Clinical
a significantly greater reduction in hs-CRP (–6.74 ± 14.65 vs. 1.81 ± 7.75 mg/L; p = 0.041)
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Dose
2,000 IU/day
Evaluating the Role of Vitamin D in Alleviating Chronic Pruritus: A Meta-Analysis.
- 2024-09-16
- Meta-Analysis
- International journal of molecular sciences 25(18)
- - Chen-Pi Li
  - Shin-Chuan Huang
  - Yao Hsiao
  - Ru-Yin Tsai
- PubMed: 39337471
- DOI: 10.3390/ijms25189983
5 Insights on
- Reduced High-Sensitivity C-Reactive Protein Level
- High evidence
- Rigorous Journal
levels of inflammatory cytokines, including tumor necrosis factor (TNF), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hs-CRP), compared to controls
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Effectiveness of vitamin D2 supplementation on high-sensitivity C-reactive protein and other metabolic indices in menopausal Thai women: a randomized-controlled trial.
- 2021-10-27
- RCT
- Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology 38(1)
- - Suchada Indhavivadhana
  - Worawat Boonyachan
  - Manee Rattanachaiyanont
  - Thanyarat Wongwananuruk
  - Kitirat Techatraisak
  - Nutchaya Sa-Nga-Areekul
- PubMed: 34704877
- DOI: 10.1080/09513590.2021.1988560
3 Insights on
- Reduced High-Sensitivity C-Reactive Protein Level
- High evidence
- Adults
The hsCRP level was significantly reduced in the vitamin D2 group (Δ of -0.39 ± 1.30 mg/L, p = .024) but not in the placebo group (Δ of -0.15 ± 1.15 mg/L, p = .521). However, the Δ of hsCRP had no statistical difference between groups
Effect
Neutral
Effect size
Small
Significant
No
Dose
40,000 IU/week

Vitamin D and Reduced High-Sensitivity C-Reactive Protein Level

Potential Modulation of Inflammation and Physical Function by Combined Probiotics, Omega-3 Supplementation and Vitamin D Supplementation in Overweight/Obese Patients with Chronic Low-Grade Inflammation: A Randomized, Placebo-Controlled Trial.

Effect of vitamin D supplementation on metabolic syndrome and atherosclerosis biomarkers in epilepsy: a randomized controlled trial.

Evaluating the Role of Vitamin D in Alleviating Chronic Pruritus: A Meta-Analysis.

Effectiveness of vitamin D2 supplementation on high-sensitivity C-reactive protein and other metabolic indices in menopausal Thai women: a randomized-controlled trial.