Vitamin C and Reduced Mortality Risk

Research synthesisLow evidenceSmall effect5 studies · 1 beneficial · 4 neutral · 0 harmful

Across 5 studies, 1 reported a beneficial moderate-sized effect of Vitamin C on reducing mortality risk in COVID-19 patients, while 4 studies found neutral small effects, primarily in sepsis populations. The median study duration was only 4 days (from 1 study reporting duration), which is too short to assess long-term mortality outcomes. Most evidence comes from clinical populations with acute critical illness.

Studied populations: patients with COVID-19, sepsis, or septic shock

Caveats: Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. Evidence base is small (only 5 studies) — conclusions should be considered preliminary. All studies focused on short-term mortality in critically ill patients, not general population mortality. Most studies used Vitamin C as part of combination therapy (e.g., with hydrocortisone and thiamine), making it difficult to isolate the effect of Vitamin C alone.

Generated Jun 11, 2026

Doses used in studies

mg/kg/day: 50 (median 50, IQR 50–50) — 1 study

Time to effect

Median: 4 days · IQR 4 days–4 days · Range 4 days–4 days — Reported in 1 of 5 studies

Safety in these studies

mortalityNo significant differenceSerious adverse event
there was no interaction between the effect of vitamin C on mortality and either platelet count at baseline or over time
from: Vitamin C Does Not Affect Platelet Counts in Patients With Sepsis: A Post hoc Analysis of
Overall tolerabilityReported
Vitamin C, despite its well-documented antioxidant and microcirculatory effects, has not yet shown consistent evidence of mortality reduction.
from: The Role of Vitamins in Sepsis: A Narrative Review.
Overall tolerabilityReported
some findings even indicating potential harm in certain patient groups
from: Beyond Fluid Therapy: The Role of Vitamin C, Steroids, and Thiamine in Sepsis Management.

5 of 5 papersPopulation:

Effects of Vitamin C Supplements on Clinical Outcomes and Hospitalization Duration for Patients with Coronavirus Disease 2019 (COVID-19): A Systematic Review and Meta-Analysis.
- 2024-11-11
- Meta-Analysis · n = 3,429
- Nutrition reviews 83(7)
- - Maorong Qin
  - Kun Xu
  - Zhuo Chen
  - Xiaojie Wen
  - Yifu Tang
  - Yangyu Gao
  - Hao Zhang
  - Xingming Ma
- PubMed: 39527016
- DOI: 10.1093/nutrit/nuae154
4 Insights on
- Reduced Mortality Risk
- High evidence
- Clinical
vitamin C supplements significantly reduced the mortality risk (OR = 0.64, 95% CI = 0.51-0.80, P = .0001)
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Dose
not stated in abstract
[Therapeutic effect of hydrocortisone combined with vitamin C and vitamin B1 on patients with sepsis: a Meta-analysis].
- 2021-09-01
- Meta-Analysis · n = 816
- Zhonghua wei zhong bing ji jiu yi xue 33(9)
- - Chenyang Chang
  - Kaiyuan Luo
  - Huifang Zhu
  - Guoping Deng
  - Qiannan Gao
- PubMed: 34839858
- DOI: 10.3760/cma.j.cn121430-20210728-01101
6 Insights on
- Reduced Mortality Risk
- High evidence
- Clinical
mortality: relative risk (RR) = 0.99, 95%CI was 0.81 to 1.21, P = 0.92
Effect
Neutral
Effect size
Small
Significant
No
Vitamin C Does Not Affect Platelet Counts in Patients With Sepsis: A Post hoc Analysis of the Lessening Organ Dysfunction With Vitamin C Randomized Trial.
- 2025-09
- RCT · n = 863
- Critical care explorations 7(9)
- - Mattia M Müller
  - Ruxandra Pinto
  - François Lamontagne
  - Neill K J Adhikari
  - Lorenzo Del Sorbo
- PubMed: 40927646
- DOI: 10.1097/cce.0000000000001310
2 Insights on
- Reduced Mortality Risk
- High evidence
- Large Human Trial
- Clinical
Although the longitudinal trajectory of platelet count was significantly associated with 28-day mortality (hazard ratio 0.97 per 10 × 10^9/L increase, 95% CI, 0.96-0.98), there was no interaction between the effect of vitamin C on mortality and either platelet count at baseline or over time.
Effect
Neutral
Effect size
Small
Significant
No
Dose
50 mg/kg body weight every 6 hours for 4 days
The Role of Vitamins in Sepsis: A Narrative Review.
- 2025-10-23
- Review
- Nutrients 17(21)
- - Paweł Radkowski
  - Anna Gogojewicz
  - Joanna Charasna
  - Łucja Pilaczyńska-Szcześniak
  - Łukasz Grabarczyk
- PubMed: 41228403
- DOI: 10.3390/nu17213330
1 Insight on
- Reduced Mortality Risk
- Moderate evidence
- Rigorous Journal
Vitamin C, despite its well-documented antioxidant and microcirculatory effects, has not yet shown consistent evidence of mortality reduction.
Effect
Neutral
Effect size
Small
Significant
No
Beyond Fluid Therapy: The Role of Vitamin C, Steroids, and Thiamine in Sepsis Management.
- 2025-05-23
- Review
- Cureus 17(5)
- - Courage O Idahor
  - Olamide Ogunfuwa
  - Ndidiamaka Ogbonna
  - Augustina Adigwe
  - Omo A Ogbeide
- PubMed: 40546532
- DOI: 10.7759/cureus.84666
6 Insights on
- Reduced Mortality Risk
- Low evidence
Combination therapy with hydrocortisone, vitamin C, and thiamine (the HAT protocol) has been associated with reduced vasopressor duration but has not consistently improved survival or other major clinical endpoints, despite its apparent safety.
Effect
Neutral
Effect size
Small
Significant
No

Vitamin C and Reduced Mortality Risk

Effects of Vitamin C Supplements on Clinical Outcomes and Hospitalization Duration for Patients with Coronavirus Disease 2019 (COVID-19): A Systematic Review and Meta-Analysis.

[Therapeutic effect of hydrocortisone combined with vitamin C and vitamin B1 on patients with sepsis: a Meta-analysis].

Vitamin C Does Not Affect Platelet Counts in Patients With Sepsis: A Post hoc Analysis of the Lessening Organ Dysfunction With Vitamin C Randomized Trial.

The Role of Vitamins in Sepsis: A Narrative Review.

Beyond Fluid Therapy: The Role of Vitamin C, Steroids, and Thiamine in Sepsis Management.