Vitamin C and Reduced Interleukin-6 Levels

Research synthesisModerate evidenceMixed effect size6 studies · 4 beneficial · 2 neutral · 0 harmful

Across 6 papers, 4 report beneficial effects of vitamin C on reducing IL-6 levels, with effect sizes ranging from small to moderate; 2 studies show neutral results. The most-studied dose is 1000 mg/day, and studies primarily involve clinical populations (e.g., cardiac surgery, septic shock, sarcopenia). Effects are observed at durations from acute single doses up to 12 weeks, with a median study duration of 28 days.

Effective dose range: 1000 mg daily
Studied populations: clinical populations (cardiac surgery, septic shock, sarcopenia, hemodialysis patients)

Caveats: Available evidence is overwhelmingly positive — clinical literature is subject to publication bias (null-result studies are less likely to be published or indexed). Many studies have small sample sizes or short durations; the effect is not always sustained beyond acute use. Results are mixed by dose and population, with some studies showing large effects (e.g., sarcopenia) and others showing no significant change (e.g., asymptomatic COVID-19).

Generated Jun 14, 2026

Doses used in studies

mg/day: 250–1,000 (median 1,000, IQR 625–1,000) — 3 studies
IU/day: 60,000 (median 60,000, IQR 60,000–60,000) — 1 study
g/day: 1 (median 1, IQR 1–1) — 1 study

Time to effect

Median: 4 weeks · IQR 7 days–8 weeks · Range 1 day–2.8 months — Reported in 5 of 6 studies

Safety in these studies

Overall tolerabilityReported
We did not observe any changes in the Siddha-based clinical examination and adverse events in both groups.
from: Kabasura Kudineer (KSK), a poly-herbal Siddha medicine, reduced SARS-CoV-2 viral load in a

6 of 6 papersPopulation:

Effect of Combined Vitamin C and Thiamine Therapy on Myocardial and Inflammatory Markers in Cardiac Surgery: A Randomized Controlled Clinical Trial.
- 2025-03-13
- RCT · n = 64
- Nutrients 17(6)
- - Mantana Saetang
  - Wirat Wasinwong
  - Maliwan Oofuvong
  - Jutarat Tanasansutthiporn
  - Laortip Rattanapittayaporn
  - Sutthasinee Petsakul
  - Pongsanae Duangpakdee
  - Puripong Rodneam
  - Parin Boonthum
  - Supphamongkhon Khunakanan
  - Chaitong Churuangsuk
  - Wilaiwan Sriwimol
  - Amphan Chantarokon
  - Kanjana Nuanjun
  - Dararat Yongsata
- PubMed: 40290059
- DOI: 10.3390/nu17061006
7 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Rigorous Journal
- Clinical
IL-6 levels were significantly lower immediately in the combined group; however, this effect was not sustained at 24 h post-surgery
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
100 mg
Individual oxidative stress and inflammation responses to vitamin C supplementation: Aggregated sets of n-of-1 trials.
- 2026-07
- RCT
- Free radical biology & medicine 250
- - George G Nastos
  - Lorenzo Lolli
  - Greg Atkinson
  - Anastasios A Theodorou
  - Vassilis Paschalis
  - Antonios Kyparos
  - Michalis G Nikolaidis
  - Nikos V Margaritelis
- PubMed: 41935704
- DOI: 10.1016/j.freeradbiomed.2026.03.073
3 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Adults
interleukin-6 by 1.2 pg/mL (CI: 0.7 to 1.7 pg/mL)
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Dose
1 g
Prognostic value of T-lymphocyte subsets, lymphocyte-to-high-density lipoprotein ratio, interleukin 6, C-reactive protein and procalcitonin in patients with septic shock and effects of vitamin C on patients with septic shock.
- 2026-01-01
- RCT · n = 110
- Pakistan journal of pharmaceutical sciences 39(1)
- - Yuyu Lu
  - Ling Wu
  - Lingling Nie
- PubMed: 41482786
- DOI: 10.36721/pjps.2026.39.1.reg.14162.1
7 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Large Human Trial
- Clinical
Post-treatment, both groups showed improved mean arterial pressure (MAP), central venous pressure (CVP) (increased), heart rate (HR) (decreased) and reduced PCT, tumor necrosis factor-α (TNF-α), IL-6 and Sequential Organ Failure Assessment (SOFA) score; however, improvements were significantly greater in the vitamin C group.
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Whey Protein, Vitamins C and E Decrease Interleukin-10 in Chronic Hemodialysis Patients: A Pioneer, Randomized, Double-Blind Pilot Trial.
- 2024-01
- RCT
- Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation 34(1)
- - Angela Teodósio da Silva
  - Roberta Pieri Machado
  - Mayara Lopes Martins
  - Luís Eduardo Gomes Dorneles
  - Eduardo Monguilhott Dalmarco
  - Edson Luiz da Silva
  - Patrícia de Fragas Hinnig
  - Elisabeth Wazlawik
- PubMed: 37598813
- DOI: 10.1053/j.jrn.2023.08.007
5 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Clinical
IL-6 tended to decrease by 810.95% in the supplementation group and increased by 732.8% (nonsignificant) in the placebo group.
Effect
Neutral
Effect size
Small
Significant
No
Dose
600 IU
Effects of vitamins C and E supplementation combined with 12-week resistance training in older women with sarcopenia: A randomized, double-blind, placebo-controlled trial.
- 2025-08-22
- RCT
- Medicine 104(34)
- - Xu Liu
  - Bo Chen
  - Yutian Jin
  - Feiyan Zhong
  - Yunjuan Zhang
  - Yu Li
  - Yun Zhang
  - Runhong Cui
  - Bing Wu
  - Cui Li
  - Sheng Xu
  - Xiaohong Chen
- PubMed: 40859523
- DOI: 10.1097/md.0000000000043976
15 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Clinical
IL-6 was lower in the AS group than in the PLA group (P < .001, d = 1.16)
Effect
Beneficial
Effect size
Large
Significant
Yes
Dose
335 mg/d
Kabasura Kudineer (KSK), a poly-herbal Siddha medicine, reduced SARS-CoV-2 viral load in asymptomatic COVID-19 individuals as compared to vitamin C and zinc supplementation: findings from a prospective, exploratory, open-labeled, comparative, randomized controlled trial, Tamil Nadu, India.
- 2021-09-15
- RCT
- Trials 22(1)
- - S Natarajan
  - C Anbarasi
  - P Sathiyarajeswaran
  - P Manickam
  - S Geetha
  - R Kathiravan
  - P Prathiba
  - M Pitchiahkumar
  - P Parthiban
  - K Kanakavalli
  - P Balaji
- PubMed: 34526104
- DOI: 10.1186/s13063-021-05583-0
7 Insights on
- Reduced Interleukin-6 Levels
- High evidence
- Clinical
There was no significant difference in the biochemical parameters.
Effect
Neutral
Effect size
Small
Significant
No
Dose
100 mg evening daily for 7 days

Vitamin C and Reduced Interleukin-6 Levels

Effect of Combined Vitamin C and Thiamine Therapy on Myocardial and Inflammatory Markers in Cardiac Surgery: A Randomized Controlled Clinical Trial.

Individual oxidative stress and inflammation responses to vitamin C supplementation: Aggregated sets of n-of-1 trials.

Prognostic value of T-lymphocyte subsets, lymphocyte-to-high-density lipoprotein ratio, interleukin 6, C-reactive protein and procalcitonin in patients with septic shock and effects of vitamin C on patients with septic shock.

Whey Protein, Vitamins C and E Decrease Interleukin-10 in Chronic Hemodialysis Patients: A Pioneer, Randomized, Double-Blind Pilot Trial.

Effects of vitamins C and E supplementation combined with 12-week resistance training in older women with sarcopenia: A randomized, double-blind, placebo-controlled trial.

Kabasura Kudineer (KSK), a poly-herbal Siddha medicine, reduced SARS-CoV-2 viral load in asymptomatic COVID-19 individuals as compared to vitamin C and zinc supplementation: findings from a prospective, exploratory, open-labeled, comparative, randomized controlled trial, Tamil Nadu, India.