Key takeaways
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This guide separates authorised vitamin C wording from the findings of the cited research. It covers food sources, supplement amounts and the conditions attached to the specific athlete-related claim.
What the vitamin C claims cover
The NHS says that adults aged 19 to 64 need 40mg of vitamin C a day and that vitamin C cannot be stored in the body, so you need it in your diet every day.
The exact EU-authorised wording is shown in the box above.
The athlete-specific immune claim (and its condition)
The exact wording and its condition of use are in the box above.
Vitamin C and colds
This is the question most people actually want answered, so let’s be direct.
A 2013 Cochrane review (Hemilä and Chalker) pooled 29 trial comparisons of regular vitamin C involving 11,306 participants; in the general community trials (10,708 participants) the pooled risk ratio of developing a cold was 0.97 (95% confidence interval 0.94 to 1.00).
There is no EU-authorised claim that vitamin C shortens a cold, so we do not state that it does; research in people under severe short-term physical stress, such as marathon runners, is a narrow research question, not a general promise.
There is no authorised EU health claim saying that vitamin C prevents colds. The EU-authorised wording for vitamin C is shown in the box above.
Getting enough: food first
The NHS says that vitamin C is found in a wide variety of fruit and vegetables. Foods often listed as sources include:
- Red and yellow peppers
- Kiwi fruit
- Citrus fruits — oranges, grapefruit, lemons
- Berries — strawberries, blackcurrants
- Broccoli and Brussels sprouts
- Tomatoes
The NHS says that you should be able to get all the vitamin C you need from your daily diet.
What about high doses?
The NHS says that taking large amounts (more than 1,000mg per day) of vitamin C can cause stomach pain, diarrhoea and flatulence, and that if you take vitamin C supplements you should not take too much as this could be harmful. No EU-authorised claim covers a performance effect of high-dose vitamin C.
Where vitamin C fits in your routine
CapyFuel’s guides cover the supplements people training seriously ask about most — whey, creatine, pre-workout, BCAAs. The exact EU-authorised wording for vitamin C is shown in the box above.
See our guides to zinc, vitamin D, magnesium and electrolyte balance for what is authorised there.
The bottom line: the NHS says that you should be able to get all the vitamin C you need by eating a varied and balanced diet, and there is no authorised EU health claim saying that vitamin C prevents colds.
Related: Vitamin D for athletes · Zinc for athletes · Magnesium for athletes · Electrolytes & hydration.
Frequently asked questions
Does vitamin C prevent colds?
A 2013 Cochrane review (Hemilä and Chalker) pooled 29 trial comparisons of regular vitamin C involving 11,306 participants; in the general community trials (10,708 participants) the pooled risk ratio of developing a cold was 0.97 (95% confidence interval 0.94 to 1.00). There is no authorised EU health claim saying that vitamin C prevents or shortens a cold.
Is there a vitamin C claim specifically for athletes?
Yes. This is one of the EU's authorised claims for vitamin C. The exact EU-authorised wording is shown in the box on this page. The condition of use is in the same box.
How much vitamin C do I need each day?
The NHS says that adults aged 19 to 64 need 40mg of vitamin C a day and that you should be able to get all the vitamin C you need from your daily diet. It lists citrus fruit, peppers, strawberries, blackcurrants, broccoli, brussels sprouts and potatoes as good sources.
Can I take too much vitamin C?
The NHS says that taking large amounts (more than 1,000mg per day) of vitamin C can cause stomach pain, diarrhoea and flatulence, and that if you take vitamin C supplements you should not take too much as this could be harmful.