Vitamin C is one of the best-known vitamins, and also one of the most misunderstood when it comes to how much you need. This guide sets out what the NHS says adults need each day, where to find vitamin C in ordinary food, how to read the figure on a supplement label, and why more isn't always better.
How much vitamin C do adults need?
According to the NHS, adults aged 19 to 64 need 40mg of vitamin C a day (NHS: Vitamin C). The NHS also says you should be able to get all the vitamin C you need from your daily diet.
The NHS also notes that vitamin C cannot be stored in the body, so you need it in your diet every day. That's the practical point: steady daily intake from food matters more than an occasional large dose.
What vitamin C does
Vitamin C (also called ascorbic acid) is an essential nutrient, and the NHS vitamin C page explains its roles in the body in plain English. It's worth reading directly rather than relying on a summary from any brand, ours included.
When it comes to what a product is allowed to say about vitamin C, the UK keeps a formal list. The Great Britain nutrition and health claims (NHC) register sets out the health claims that may be used on foods and supplements. Claims authorised for vitamin C include that it contributes to the reduction of tiredness and fatigue, to the normal function of the immune system, and to normal collagen formation for the normal function of blood vessels. We look at what that wording does and doesn't mean in Vitamin C and tiredness: what the UK health claim means.
Good food sources of vitamin C
Vitamin C is found in a wide range of fruit and vegetables. The NHS lists these as good sources (NHS):
- citrus fruit, such as oranges and orange juice
- peppers
- strawberries
- blackcurrants
- broccoli
- brussels sprouts
- potatoes
Potatoes are the one people overlook. They are an everyday staple in many UK households, and the NHS lists them as a good source. A varied diet with fruit and vegetables at most meals is the simplest way to cover the 40mg figure.
Practical ways to keep vitamin C in your day
- Spread it out. Because vitamin C isn't stored, a piece of fruit or a portion of vegetables at more than one meal is a sensible habit.
- Keep frozen options in. Frozen fruit and vegetables are convenient for days when fresh isn't to hand.
- Think about cooking. Many people steam or microwave vegetables, or eat some raw (peppers, for example), rather than boiling them for a long time.
- Don't forget the basics. Potatoes, broccoli and a glass of orange juice are all on the NHS list. Vitamin C doesn't have to come from anything special.
Can you have too much vitamin C?
Yes. The NHS says that taking large amounts (more than 1,000mg a day) of vitamin C can cause stomach pain, diarrhoea and flatulence, and that these symptoms should disappear once you stop taking vitamin C supplements (NHS).
The Department of Health and Social Care advice, as quoted by the NHS, is that you should be able to get all the vitamin C you need from a varied and balanced diet. If you take supplements, don't take too much, as this could be harmful. Taking less than 1,000mg of vitamin C supplements a day is unlikely to cause any harm.
Many products contain vitamin C, including multivitamins, some drinks and some herbal supplements. If you take more than one, add up the vitamin C across all of them using the figures on each label.
Reading vitamin C on a supplement label
In Great Britain, a food supplement label must state the amount of any vitamin or mineral in the product, along with the recommended daily dose and a warning not to exceed it (GOV.UK: Food supplements guidance). In practice you'll usually see two figures next to vitamin C:
- An amount in milligrams (mg), normally per recommended daily dose. The NHS overview explains the units: a milligram is one thousandth of a gram (NHS: Vitamins and minerals).
- A percentage of the NRV. NRV stands for nutrient reference value, a standard reference figure used on labels. It lets you compare products on a like-for-like basis.
Two things to check. First, whether the figure is per serving or per daily dose, because they differ when a product is taken more than once a day. Second, the recommended daily dose itself, because the amount you actually take depends on following it.
Note that the NRV on a label and the NHS figure of 40mg for adults are different reference points used for different purposes. Use the NHS figure to think about your diet, and the label figures to compare products and add up what you're taking.
Who should check with a GP or pharmacist
Most adults get enough vitamin C from food. Speak to your GP or pharmacist before adding a supplement if you:
- are pregnant or breastfeeding
- take regular medication
- have a long-term health condition, or have been told to follow a special diet
- are already taking several supplements and aren't sure about the total
If you're worried about any symptom, including persistent tiredness, see your GP rather than relying on a supplement.
Where Havern fits
Havern Herbal Drops contain vitamin C as sodium ascorbate alongside nine botanicals in a vegetable glycerine base, made in the UK. Check the label for the exact vitamin C amount if you are adding it to anything else you take.
Havern is a food supplement, made in the UK. It isn't a replacement for fruit and vegetables, and it isn't a medicine.
The short version
- The NHS says adults aged 19 to 64 need 40mg of vitamin C a day, and most people can get this from food.
- Vitamin C isn't stored in the body, so you need some every day.
- Good sources include citrus fruit, peppers, strawberries, blackcurrants, broccoli, brussels sprouts and potatoes.
- More than 1,000mg a day from supplements can cause stomach upset. Add up every product you take.
- On labels, check whether the figure is per serving or per daily dose.
Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Do not exceed the stated dose.