Vitamin C and Reduced Interleukin-6 Levels

Research synthesisModerate evidenceSmall effect7 studies · 4 beneficial · 3 neutral · 0 harmful

Across 7 studies, 4 reported beneficial effects of vitamin C on reducing interleukin-6 levels, with effect sizes ranging from small to moderate, while 3 found neutral effects. The median study duration was 28 days, though effects were observed in both acute (1-day) and longer-term (84-day) settings. Most studied populations were clinical (e.g., cardiac surgery, septic shock, hemodialysis patients), and doses ranged from 250 mg to 1000 mg/day.

Effective dose range: 250-1000 mg/day
Studied populations: clinical populations (cardiac surgery patients, septic shock patients, hemodialysis patients, older women with sarcopenia)

Caveats: Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. Several studies used vitamin C in combination with other interventions (thiamine, whey protein, vitamin E), making it difficult to isolate the effect of vitamin C alone. The evidence base includes only 7 studies, and beneficial findings are concentrated in acute clinical settings; generalizability to healthy populations is uncertain.

Generated Jul 10, 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 7 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

7 of 7 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
The impact of vitamin C supplementation on the perioperative outcomes after total hip and knee arthroplasty: a systematic review and meta-analysis.
- 2025-10-01
- Meta-Analysis · n = 852
- BMC musculoskeletal disorders 26(1)
- - Xiaoya Liu
  - Jiayi Guo
  - Yapeng Li
  - Yidan Yang
  - Mengyao Liu
  - Qi Gao
  - Yuxia Yang
  - Xiaolong Wu
  - Chen Yue
- PubMed: 41034912
- DOI: 10.1186/s12891-025-09163-0
9 Insights on
- Reduced Interleukin-6 Levels
- High evidence
no significant differences were observed in these outcomes at 48 h postoperatively (P > 0.05)
Effect
Neutral
Effect size
Small
Significant
No
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.

The impact of vitamin C supplementation on the perioperative outcomes after total hip and knee arthroplasty: a systematic review and meta-analysis.

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.