Also called retinol
Vitamin A
A fat-soluble vitamin (retinol) used to treat deficiency, which is a cause of night blindness, and in some specialist situations.
What is Vitamin A?
Vitamin A, also called retinol, is a fat-soluble vitamin that the body needs for healthy vision, skin and immune function. It is used to treat or prevent vitamin A deficiency, which is a cause of night blindness, and in some specialist situations. The most important safety point is that high amounts are harmful in pregnancy because they can cause birth defects, so high-dose supplements should not be taken when pregnant. Taking too much over time can also cause liver and bone problems, so it should be used as advised rather than in large amounts.
Education and reference only. This is a plain-language guide to Vitamin A — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Vitamin A, known as retinol, is a fat-soluble vitamin that the body needs for normal vision (especially seeing in dim light), healthy skin, and a working immune system. Most people get enough from a balanced diet, but supplements are used to treat or prevent deficiency, which is uncommon in the UK but a serious problem in some parts of the world where it causes night blindness and eye damage. It is also used in some specialist medical situations under guidance. Because it is fat-soluble, it can build up in the body, so it is important not to take too much.
How it works
Vitamin A plays several roles in the body: it is essential for the cells in the eye that allow us to see in dim light, which is why a lack of it causes night blindness, and it helps keep skin, surfaces inside the body and the immune system healthy. When given as a supplement to someone who is deficient, it simply restores the level the body needs to work normally. Because it is fat-soluble, the body stores it rather than passing out the excess, so taking more than needed allows it to build up and become harmful over time.
Company & origin
Originated / developed by: Various manufacturers.
A fat-soluble vitamin used in the UK to treat or prevent deficiency, and in some specialist situations.
Practical use
How to take Vitamin A
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it only as advised, as too much can build up in the body and become harmful.
- Do not take high-dose vitamin A supplements if you are pregnant or might become pregnant, because of the risk of birth defects.
- Avoid taking several different supplements that all contain vitamin A, to prevent the amounts adding up.
- If you are pregnant, also avoid foods very rich in vitamin A, such as liver, on advice.
- Take it as part of food where advised, as it is absorbed better with some fat.
Weighing it up
Advantages & disadvantages of Vitamin A
Advantages
- Effectively treats and prevents vitamin A deficiency, a cause of night blindness and eye damage.
- Supports normal vision, skin and immune function when the body is short of it.
- Useful in some specialist medical situations under guidance.
Disadvantages
- High amounts are harmful in pregnancy and can cause birth defects.
- Because it is stored in the body, taking too much over time can cause liver and bone problems.
- Most people in the UK get enough from diet, so supplements are not needed without a reason.
Practical use
Good to know
The most important thing to know about vitamin A is that too much is harmful, and the situation that matters most is pregnancy: high amounts can cause birth defects, so high-dose supplements and foods very rich in vitamin A, such as liver, should be avoided when pregnant or planning a pregnancy. Because the vitamin is fat-soluble and stored in the body, taking too much over a long time can also cause liver problems and weaken the bones, as well as causing headaches and skin changes. For most people in the UK a balanced diet provides enough, so supplements are only needed for deficiency or specific medical reasons. Always follow the dose you are given and avoid taking several supplements that all contain vitamin A.
Who should not take it / use with caution
- People who are pregnant or might become pregnant should not take high-dose vitamin A supplements, because of the risk of birth defects.
- People who have had a serious allergic reaction to a vitamin A preparation should not take it.
- It is used with care in people with liver problems, who store and handle it differently.
Monitoring
- Reviewing whether a supplement is actually needed and at what amount.
- Watching for signs of too much, such as headaches, skin changes or bone and joint pain.
- Taking particular care to avoid high doses in anyone who is or may become pregnant.
Side effects
- When taken in large amounts over time: headaches, tiredness, and dry or peeling skin.
- Bone and joint pain, and over the long term, weakening of the bones.
- Liver problems with prolonged high intake, which is why large amounts should be avoided.
Key interactions
- Other supplements or treatments containing vitamin A or related retinoids can add up, raising the risk of too much.
- Some acne and skin treatments are related to vitamin A, so tell your prescriber if you take these.
- Always share your full list of supplements and medicines to avoid amounts adding up.
Available as: Capsules, tablets and liquid preparations, and part of some combined supplements.
Answers
Vitamin A: frequently asked questions
What is vitamin A used for?
It is used to treat or prevent vitamin A deficiency, which is a cause of night blindness and eye damage, and in some specialist medical situations.
Is vitamin A safe in pregnancy?
High amounts are harmful in pregnancy and can cause birth defects, so high-dose supplements and very rich sources such as liver should be avoided when pregnant or planning a pregnancy.
Can you take too much vitamin A?
Yes. Because it is stored in the body, taking too much over time can cause headaches, skin and bone problems, and liver problems, so follow the dose you are given.
Do I need a supplement?
Most people in the UK get enough from a balanced diet, so a supplement is usually only needed for deficiency or a specific medical reason.
Why is it linked to seeing in the dark?
Vitamin A is essential for the cells in the eye that let us see in dim light, which is why a lack of it causes night blindness.
Authoritative sources
- BNF
- NICE CKS
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