Vitamin D and Reduced Interleukin-6 Levels

Research synthesisModerate evidenceModerate effect8 studies · 5 beneficial · 3 neutral · 0 harmful

Vitamin D supplementation shows moderate evidence for reducing IL-6 levels. Among 8 studies, 5 reported beneficial effects with a predominant moderate effect size, while 3 found no significant change. The median study duration was 56 days, and most studies used daily doses between 200 and 5000 IU in clinical populations such as colorectal cancer patients, overweight/obese adults, and those with low-grade inflammation.

Caveats: Most studies were conducted in specific clinical populations (e.g., CRC, obesity, psoriasis), limiting generalizability to healthy adults. Several studies had low evidence scores due to small sample sizes or review designs. Doses varied widely (200–5000 IU/day or single high dose), and no supplement form data were available. Four of eight studies did not reach statistical significance, suggesting the effect may be modest or inconsistent.

Generated Jul 12, 2026

Doses used in studies

IU/day: 200–5,000 (median 1,000, IQR 600–3,000) — 3 studies
IU single-dose: 300,000 (median 300,000, IQR 300,000–300,000) — 1 study

Time to effect

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

Safety in these studies

Overall tolerabilityNo significant differencerisk ratio 1.02, 95% CI 0.94-1.10
Adverse events were comparable across interventions (risk ratio 1.02, 95% CI 0.94-1.10).
from: Effectiveness and safety of dietary supplements in the adjunctive treatment of psoriasis:

8 of 8 papersPopulation:

Effects of personalized vitamin D3 on inflammation in colorectal cancer patients: a randomized trial.
- 2026-01-08
- RCT · n = 126
- British journal of cancer 134(6)
- - Tafirenyika Gwenzi
  - Alexander N R Weber
  - Kira Trares
  - Tomislav Vlaski
  - Marija Slavic
  - Sha Sha
  - Edelmann Dominic
  - Reiner Caspari
  - Bettine Bilsing
  - Harald Fischer
  - Cristina-Maria Fernandes-Almeida
  - David Czock
  - Ben Schöttker
  - Hermann Brenner
- PubMed: 41507560
- DOI: 10.1038/s41416-025-03333-6
3 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Large Human Trial
- Clinical
The VIDS group exhibited 39.3% reduction in IL-6 levels compared to the placebo group (95% CI: -54.9% to -18.2%; p = 0.001).
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Dose
personalized loading dose followed by 2000 IU/day maintenance
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 Interleukin-6 Levels
- High evidence
- Rigorous Journal
- Clinical
Interleukin (IL)-6 levels decreased in the treatment group (p = 0.018).
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
200 IU of vitamin D
Efficacy of vitamin D supplementation in patients diagnosed with depression: a dose-response meta-analysis of randomized controlled trials.
- 2026-03-17
- Systematic Review · n = 962
- Frontiers in nutrition 13
- - Hsuan-Hsien Liu
  - Ting-Hui Liu
  - Chia-Yu Liu
  - Jheng-Yan Wu
  - Chien-Ho Lin
  - Chih-Cheng Lai
- PubMed: 41923913
- DOI: 10.3389/fnut.2026.1772451
6 Insights on
- Reduced Interleukin-6 Levels
- High evidence
while other outcomes, such as BMI, weight, and IL-6, showed no significant changes.
Effect
Neutral
Effect size
Small
Significant
No
Dose
up to 5,000 IU/day
Effectiveness and safety of dietary supplements in the adjunctive treatment of psoriasis: a systematic review and network meta-analysis.
- 2025-12-11
- Systematic Review · n = 463
- Frontiers in nutrition 12
- - Danping Chen
  - Jie Yang
  - Wenwen Yang
  - Xinying Liu
  - Zhihong Li
- PubMed: 41459063
- DOI: 10.3389/fnut.2025.1718828
3 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Clinical
vitamin D + NB-UVB most consistently lowered IL-6/IL-17/IL-23
Effect
Beneficial
Effect size
Small
Significant
No
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 Interleukin-6 Levels
- 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
Co-administration of vitamin D and N-acetylcysteine to modulate immunosenescence in older adults with vitamin D deficiency: a randomized clinical trial.
- 2025-05-12
- RCT
- Frontiers in immunology 16
- - Samira Rastgoo
  - Katayoun Pourvali
  - Seyed Ahmad Raeissadat
  - Ghazaleh Eslamian
  - Hamid Zand
- PubMed: 40421021
- DOI: 10.3389/fimmu.2025.1570441
6 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Clinical
No significant differences were observed between the groups in serum IL-6 ... after the intervention.
Effect
Neutral
Effect size
Small
Significant
No
Dose
1000 IU daily
Effects of Vitamin D3 Supplementation on Inflammatory Markers in Overweight and Obese Children and Adolescents: A Systematic Review.
- 2025-07-20
- Review · n = 294
- Life (Basel, Switzerland) 15(7)
- - Maria Krajewska
  - Ewelina Witkowska-Sędek
- PubMed: 40724644
- DOI: 10.3390/life15071142
5 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Children
We found that vitamin D3 supplementation did not affect the changes in ... interleukin-6 (IL-6)
Effect
Neutral
Effect size
Small
Significant
No
Investigating the Effect of High-Dose Vitamin D3 Administration on Inflammatory Biomarkers in Patients with Moderate to Severe Traumatic Brain Injury: A Randomized Clinical Trial.
- 2024-10-01
- RCT
- Iranian journal of medical sciences 49(10)
- - Farnoosh Masbough
  - Mehran Kouchek
  - Mohsen Koosha
  - Sara Salarian
  - Mirmohammad Miri
  - Masoomeh Raoufi
  - Niloufar Taherpour
  - Saied Amniati
  - Mohammad Sistanizad
- PubMed: 39449769
- DOI: 10.30476/ijms.2023.99465.3156
6 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Clinical
IL-6 (-88.05±148.45, in the intervention group: P=0.0001 vs. -35.54±175.79, in the control groupL P=0.325) 3 days after the intervention
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Dose
single intramuscular dose of 300,000 IU