Vitamin C for Exercise-Induced Immune Suppression
BResearch suggests regular vitamin C supplementation may reduce post-exercise URTI incidence in athletes, military personnel, and individuals under extreme physical stress. Benefits appear more pronounced in those exposed to severe physical stress.
The Bottom Line
Research suggests regular vitamin C supplementation may reduce post-exercise URTI incidence in athletes, military personnel, and individuals under extreme physical stress. Benefits appear more pronounced in those exposed to severe physical stress.
Key Study Findings
Population: Children with inflammatory bowel disease (review)
Population: Broiler chickens
Population: None
Population: men
Population: Pregnant women
Population: General population
Key Statistics
5
Studies
600
Participants
Positive
Grade
Referenced Papers
Dosage & Usage
mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units
Commonly Used Dosages
- general:
- 75-90 mg/day
- acuteillness:
- 1,000-2,000 mg/day
- immunesupport:
- 200-1,000 mg/day
Upper limit: 2,000 mg/day
Dosages Studied in Research
| Dosage | Duration | Effect | N |
|---|---|---|---|
| None | -- | Neutral | -- |
| None | -- | Positive | -- |
| 45% | 988 weeks | Positive | 26282 |
| None | -- | Mixed | -- |
| None | -- | Positive | -- |
| Probiotics, prebiotics, fatty acids, vitamins | -- | Positive | -- |
| Vitamin C, E, glutamine, zinc | -- | Positive | -- |
| None | 2.0 weeks | Mixed | -- |
Best taken: With meals; divide doses >500 mg for better absorption
Safety & Side Effects
Reported Side Effects
- ⚠ Gastrointestinal distress (nausea, diarrhea, cramps) at high doses
- ⚠ Increased risk of kidney stones in susceptible individuals
- ⚠ Interference with certain lab tests (glucose, occult blood)
- ⚠ Iron overload risk in hemochromatosis patients
Known Interactions
- ● Enhances non-heme iron absorption (beneficial or harmful depending on iron status)
- ● High doses may reduce effectiveness of certain chemotherapy agents
- ● May interfere with anticoagulant therapy (warfarin) at high doses
- ● Aluminum-containing antacids (increased aluminum absorption)
Tolerable upper intake: 2,000 mg/day
Always consult your healthcare provider before starting any supplement.
Frequently Asked Questions
Does Vitamin C help with Exercise-Induced Immune Suppression?
How much Vitamin C should I take for Exercise-Induced Immune Suppression?
Are there side effects of Vitamin C?
How strong is the evidence for Vitamin C and Exercise-Induced Immune Suppression?
Related Evidence
Other ingredients for Exercise-Induced Immune Suppression
Vitamin C for other conditions
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.