Folic acid is the man-made version of the vitamin folate (also known as vitamin B9).
It's available on prescription and comes as tablets. You can also buy lower dose tablets from pharmacies and supermarkets.
Brand names include Clonfolic and Active Folic. Ask your pharmacist which is best for you.
Important
Women who can get pregnant should take a 400 micrograms (mcg) folic acid supplement every day, even if you do not plan to get pregnant.
Folic acid may also be available with:
- ferrous fumarate and ferrous sulphate (to treat iron deficiency anaemia)
- other vitamins and minerals (as a multivitamin and mineral supplement)
Uses of folic acid
Folic acid is used to:
- treat or prevent folate deficiency anaemia, which impacts on how well your red blood cells work
- help your unborn baby's brain, skull and spinal cord develop properly during pregnancy - this helps to avoid problems such as spina bifida
- help reduce side effects from methotrexate, a medicine used to treat severe arthritis, Crohn's disease or psoriasis
If you're trying for a baby, it's best to take folic acid for at least 14 weeks before you become pregnant. You should continue taking it for at least the first 12 weeks of pregnancy.
When you start taking folic acid
Folic acid is absorbed very quickly in the gut once taken.
If you're taking it for folate deficiency anaemia, it may be a few weeks before you start to feel better.
If you're taking it because you're pregnant, you probably will not feel any different, but that does not mean it's not working.
You're unlikely to get side effects with folic acid, but some people feel sick, lose their appetite, get wind or feel bloated. These side effects are usually mild and do not last long.
Do not drink alcohol with folic acid as it may stop folic acid being absorbed. It's also safer not to drink any alcohol if you're pregnant or trying to get pregnant because it can damage your baby's growth.
Check if you can take folic acid
Most adults and children can take folic acid.
To make sure it's safe for you, tell a doctor or pharmacist before you start taking folic acid if you have:
- had an allergic reaction to folic acid or any other medicine
- low vitamin B12 levels (vitamin B12 deficiency anaemia) or pernicious anaemia
- cancer
- a type of kidney dialysis called haemodialysis
- a stent in your heart
Folic acid and breastfeeding
Folic acid is safe to take while you're breastfeeding. It passes into your milk, but it's not harmful to your baby.
If your baby is premature or has health problems, check with your GP first.
How to take it
Follow your GP's instructions about how and when to take folic acid, if it was prescribed for you or your child for folate deficiency.
Follow the instructions that come with the packet, if you have bought folic acid without a prescription from a pharmacy or shop.
Before and during pregnancy
All women who can get pregnant should take a 400 micrograms (mcg) folic acid supplement every day. They should do this even if they are not planning to get pregnant.
Your GP may recommend a higher dose of folic acid if you have certain medical conditions.
If you're pregnant or trying for a baby, take folic acid until you're 12 weeks pregnant. It helps your baby grow normally.
Folic acid when planning a pregnancy
When to take it
You usually take folic acid once a day, but sometimes you only need to take it once a week.
You can take folic acid with or without food. Swallow the tablets whole with a drink.
If you forget to take it
Missing 1 or 2 doses will not matter.
Never take 2 doses to make up for a forgotten one.
If you take folic acid once a day
Take your missed dose as soon as you remember.
If it's nearly time for your next dose, skip the missed dose and just take your next dose as normal.
If you take folic acid once a week
Take your missed dose as soon as you remember, unless you take methotrexate that day.
If you remember on the day you take your methotrexate, wait a day and take your missed dose the following day. After this, go back to taking your weekly dose on your usual day.
If you take too much
Folic acid is generally very safe. Taking too much is unlikely to harm you or your child. Speak to a pharmacist or your GP if you're worried.
Side effects
There are things you can do to help cope if you get these side effects of folic acid:
Feeling sick (nausea)
Take folic acid with, or just after, a meal or snack to help with feeling sick.
If you're pregnant, it could be morning sickness that's making you feel sick. If you have pregnancy sickness, try taking folic acid at a time of day when you feel better.
Loss of appetite
Eat when you'd usually expect to be hungry. If it helps, eat smaller meals more often than usual. Have nutritious snacks that are high in calories and protein, such as dried fruit and nuts.
Bloating or wind
It might help to eat smaller and more frequent meals, eat and drink slowly, and exercise regularly. If the symptoms get worse, contact your GP straight away.
Speak to a GP or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious allergic reaction
Serious allergic reaction to folic acid is rare. But if happens you will need to go to the emergency department (ED).
Emergency action required: Call 112 or 999 or go to an emergency department (ED) straight away if you:
- get a skin rash that may include itchy, red, swollen, blistered or peeling skin
- are wheezing
- get tightness in the chest or throat
- have trouble breathing or talking
- feel your mouth, face, lips, tongue or throat start to swell
These are warning signs of a serious allergic reaction (anaphylaxis).
Non-urgent advice: Find your patient information leaflet
Your patient information leaflet is the leaflet that comes with your medicine. You can find a digital version of the leaflet online.
Report side effects
You can report any suspected side effects to the Health Products Regulatory Authority (HPRA): report an issue - hpra.ie
Taking folic acid with other medicines
Some medicines interfere with the way folic acid works. If you’re on any other medicines or supplements, check with your GP, a pharmacist or nurse before you start taking folic acid.
Do not take your folic acid within 2 hours before or after taking indigestion remedies (antacids containing aluminium or magnesium), as they may stop folic acid being properly absorbed.
Herbal remedies
Some vitamin and mineral supplements already contain folic acid. It's important not to take more than the recommended daily amount.
Tell your pharmacist or GP if you take any supplements or remedies that contain zinc. Folic acid can stop zinc working as well as it should.
Everyday painkillers
You can take folic acid at the same time as everyday painkillers, for example paracetamol.
Talk to your GP before taking any non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin, if you're taking folic acid with methotrexate.
Fact check
This content was fact checked by a pharmacist, a GP, and the National Medication Safety Programme (Safermeds).
