Vitamin C is the most popular cold remedy there is. The research gives a clear but modest answer: it won’t stop most people catching colds, but taking it regularly can make them a little shorter.
What the research shows
- Prevention: for most people, taking vitamin C every day doesn’t reduce how many colds they get.
- Shorter colds: people who take it regularly have slightly shorter colds, by about 8% in adults and 14% in children. That’s roughly half a day off a week-long cold.
- Under heavy physical stress: people such as marathon runners and soldiers in extreme cold had about half as many colds when taking vitamin C.
- Starting when symptoms begin: taking vitamin C only once a cold has started hasn’t shown a consistent benefit.
How much is safe?
- The recommended daily amount is 90 mg for men and 75 mg for women, plus 35 mg for smokers.
- The upper limit for adults is 2,000 mg a day. Above that, diarrhoea, nausea and stomach cramps become more likely.
- High doses over time may raise the risk of kidney stones, especially in men. If you’ve had kidney stones, ask your doctor first.
Read more in how much vitamin C do you need.
Food first
Oranges, kiwi, strawberries, bell peppers, broccoli and tomatoes are all rich in vitamin C. One orange gives about 70 mg. A supplement such as Sundown Naturals Vitamin C can help if your diet falls short.
Other things that can help a cold
- Rest and fluids.
- Honey for cough in adults and children over 1 year (never give honey to babies under 1).
- Zinc lozenges started within 24 hours may shorten a cold slightly. They can cause a bad taste and nausea.
- Saline nose sprays and warm drinks for congestion.
- Pain relievers for aches and fever, following the label.
Not sure if it’s a cold or allergies? See allergies or a cold: how to tell.
See a doctor if
Symptoms last more than 10 days, you have a high fever, trouble breathing, chest pain or a severe sore throat, or a baby or older adult is unwell.
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This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Always read the label before using any medicine.
