In 1747, a British naval surgeon divided 12 sick sailors into six pairs. Some got vinegar. Others got seawater or cider. One pair received oranges and lemons. The citrus group improved remarkably quickly. James Lind had found a useful answer to scurvy, although nobody aboard the Salisbury knew what a vitamin was.
Nearly three centuries later, vitamin C is still surrounded by questions. Can it keep a runner from catching a cold? Does a bigger dose help after a hard workout? And is an orange enough? The answers are more interesting than the familiar promise to “boost immunity.”
The citrus experiment that preceded the vitamin
Lind's trial was tiny by modern standards: just two sailors per treatment. Nor was he the first person to notice that citrus helped people with scurvy. But comparing several remedies aboard one ship was an unusually systematic way to ask a practical question. It took decades for citrus rations to become widespread in the Royal Navy.
The chemistry came much later. Albert Szent-Györgyi isolated a substance he called hexuronic acid in 1928. Researchers subsequently connected it to the antiscorbutic factor, and the substance became known as ascorbic acid: vitamin C. The name essentially means “against scurvy.” That is a much firmer claim than most claims made about supplements today. Severe deficiency causes scurvy; restoring adequate vitamin C corrects that deficiency.
What vitamin C actually does
Vitamin C is water-soluble and essential. Humans cannot make it, so we need it from food or supplements. It helps enzymes produce collagen, a structural protein in connective tissues. It also supports normal immune function, acts as an antioxidant, and improves absorption of nonheme iron, the type found in beans, grains and vegetables.
Those functions matter to runners, but there is an important distinction. A nutrient being necessary for normal tissue function does not mean taking extra improves running performance. Water is necessary, too. That does not make a third water bottle a speed workout.
Vitamin C also participates in the body's handling of reactive oxygen species. Exercise creates some oxidative stress, but those chemical signals are not simply waste to eliminate. They help initiate training adaptations. That is one reason high-dose antioxidant supplements deserve more scrutiny than an ordinary serving of fruit.
How much vitamin C do adult runners need?
The U.S. recommended dietary allowance is 90 mg daily for adult men and 75 mg for adult women. Adults who smoke need an additional 35 mg per day. These are general nutritional targets, not special marathon doses. There is no established separate vitamin C RDA for recreational runners.
| Food | Practical serving | Why it helps |
|---|---|---|
| Red bell pepper | Half a cup, raw | A concentrated source of vitamin C |
| Orange | One medium fruit | Convenient vitamin C with fluid and carbohydrate |
| Kiwi | One fruit | Easy breakfast or snack addition |
| Strawberries | Half a cup | Works in oatmeal or yogurt |
| Broccoli | Half a cup, cooked | Adds vitamin C to a normal meal |
Actual amounts vary by portion, variety, storage and preparation. Vitamin C can be lost during prolonged cooking or storage. The point is not to count every milligram. A varied diet containing produce most days makes an adequate intake quite achievable.
Does vitamin C stop runners from getting colds?
Here the research needs careful reading. In the general population, regularly taking at least 200 mg per day has not consistently reduced the number of people who catch a cold. It has modestly shortened cold duration in some pooled trials. Starting vitamin C after symptoms appear has not shown a reliable benefit.
There is an intriguing exception. Trials involving marathon runners, skiers and soldiers exposed to extreme exertion or cold found that regular supplementation, generally between 250 mg and 1,000 mg daily, reduced cold incidence by about half in those particular study populations. That is a pooled result from unusually demanding circumstances, not a prediction for every 45-year-old who runs four mornings a week.
Even the word “cold” deserves care: many studies relied on reported symptoms, not laboratory confirmation of a specific virus. The research suggests a possible benefit in certain high-stress settings. It does not establish that a daily multivitamin prevents illness or that more vitamin C is always better.
What about soreness, recovery and faster race times?
Biological plausibility is not the same as a demonstrated outcome. Vitamin C contributes to collagen synthesis, but that alone does not establish that extra vitamin C prevents running injuries or speeds tissue repair in well-nourished adults.
Consider an 11-week randomized endurance-training study described by the NIH. Fifty-four young adults received either placebo or 1,000 mg vitamin C plus 235 mg vitamin E daily while training. The supplement group showed reduced markers of mitochondrial signaling and adaptation. Yet the groups did not differ meaningfully in VO2max or running performance. The biochemical change was real; an actual decline in race performance was not demonstrated.
That distinction cuts both ways. We should not claim the vitamins ruined fitness, and we should not claim that blunting oxidative markers automatically improves recovery. Evidence for routine high-dose vitamin C as an endurance performance supplement is weak. Food, sufficient calories, carbohydrates around demanding sessions, protein across the day and sleep remain more dependable priorities.
When might a supplement make sense?
A supplement can help fill a genuine dietary gap, particularly during periods when eating a varied diet is difficult. But check the amount before adding another bottle. A supplement delivering 100 mg is a different proposition from a daily 1,000 mg dose, and the evidence from one cannot be casually transferred to the other.
Vitamin C supplements commonly use ascorbic acid or mineral ascorbates. The NIH reports no convincing evidence that one common form is superior for ordinary vitamin C status. The adult tolerable upper intake level is 2,000 mg per day, not a target. High intakes can cause diarrhea, nausea and cramps, and particular medical conditions or medications may change the risk calculation.
One useful food pairing is a vitamin-C-rich pepper or citrus fruit with a plant-based iron source such as beans or lentils. Vitamin C improves nonheme iron absorption at that meal. That is a nutrient-absorption effect, not proof that the pairing increases hemoglobin or running speed in someone whose iron status is already adequate.
Why We Include Vitamin C in PEREGRUNE
Our PEREGRUNE Runner Multivitamin provides 333 mg of vitamin C (370% Daily Value) as ascorbic acid per two-tablet serving, helping supplement your diet with a nutrient that supports normal immune function and collagen production.
In studies involving marathon runners and other people under extreme physical stress, regular vitamin C supplementation at roughly 250–1,000 mg daily reduced the incidence of reported cold symptoms. Our 333 mg serving falls within that studied range, although the finished PEREGRUNE formula has not been tested for that outcome.
That's our approach: practical nutritional support to complement good food and consistent training, even when work and family make perfect eating unrealistic.
Frequently asked questions
Should I take vitamin C immediately after a long run?
There is no established post-run vitamin C timing window. Eat a normal recovery meal or snack that supplies the energy and protein you need, and include fruit or vegetables as convenient.
Is 1,000 mg better than 100 mg?
Not necessarily. Larger doses were studied in some cold and exercise trials, but they have not consistently improved endurance outcomes. The best dose depends on dietary adequacy and the specific reason for supplementing.
Can vitamin C help absorb iron?
Yes, vitamin C increases absorption of nonheme iron from plant foods. That does not replace assessment of suspected iron deficiency or establish that everyone should take an iron supplement.
The bottom line
Lind's sailors needed a missing nutrient, and citrus supplied it. Modern runners generally face a different question: whether more than enough is better. Usually the first move is simpler. Eat produce regularly, avoid treating megadoses as insurance, and keep the claims about colds and performance tied to the people and doses actually studied. Your next good run probably starts with breakfast, not a chemistry experiment.
Sources
- NIH Office of Dietary Supplements: Vitamin C, Health Professional Fact Sheet
- NIH ODS: Dietary Supplements for Exercise and Athletic Performance
- Carpenter KJ. The discovery of vitamin C. Annals of Nutrition and Metabolism (2012)
- James Lind Library: Who was James Lind, and what exactly did he achieve?
Educational information only. Dietary supplements are not intended to diagnose, treat, cure or prevent disease. Consult a qualified clinician about personal medical concerns, medications or suspected deficiencies.