Do I need folic acid tablets?
Only if you could get pregnant, or a doctor prescribes them. For pregnancy, 400 micrograms a day. Most other adults should be able to get enough from food. More isn’t safer. One vitamin explains why.
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Who needs folic acid tablets?
Anyone who could get pregnant. The NHS advises 400 micrograms of folic acid a day if you’re pregnant, trying for a baby or could get pregnant. Keep going until you’re 12 weeks pregnant.
It lowers the chance of problems with a baby’s brain or spine, such as spina bifida. And it’s difficult to get enough from food alone.
Men, and women who can’t get pregnant, should be able to get all the folate they need from a varied, balanced diet. Adults need 200 micrograms of folate a day.
| Who | Folic acid | Where from |
|---|---|---|
| Could get pregnant, trying, or under 12 weeks pregnant | 400 micrograms a day | Buy it, or get it free with Healthy Start if you qualify. |
| Higher chance of a baby with a brain or spine problem (neural tube defect) | 5 mg a day until 12 weeks | Prescribed by a GP. |
| Folate deficiency anaemia (too few healthy red blood cells because of low folate) | Daily tablets, for about 4 months for most people | Prescribed by a GP after a B12 check. |
| On methotrexate (for arthritis, Crohn’s or psoriasis) or kidney dialysis | As prescribed | Your doctor. |
| Men, and women who can’t get pregnant | Usually none. Food should cover the 200 micrograms a day. | Greens, peas, beans and fortified cereals. |
Sources: NHS vitamin B; NHS pregnancy; NHS folic acid; NHS treatment
Good food sources include broccoli, sprouts, spinach, peas, chickpeas and fortified breakfast cereals (cereals with vitamins added). Your body keeps no long-term store, so eat them often.
Think you might be low? Ask your GP about a folate blood test before you buy tablets.
Which folic acid tablets are best for pregnancy?
Look for 400 micrograms of folic acid, in a plain tablet or a multivitamin. Pregnant? Check with a doctor or pharmacist before taking a multivitamin with folic acid.
| On the label | What it means |
|---|---|
| 400 mcg or 400 µg | 400 micrograms. The usual pregnancy dose. |
| 5 mg | The higher dose. A GP prescribes it. |
| Vitamin A, retinol or cod liver oil | Avoid in pregnancy. Too much vitamin A can harm your baby’s development. |
| Methylfolate or 5-MTHF | A different form of folate. Trials on preventing spina bifida are lacking. |
Sources: NHS pregnancy; Nutrients review
The NHS advises the 5 mg dose if you’re planning a pregnancy or less than 12 weeks pregnant and:
- you or the baby’s father has a neural tube defect (a problem with the brain or spine)
- you or the baby’s father has a relative with one
- you’ve had a past pregnancy affected by one
- you have diabetes
- you have a blood condition such as sickle cell anaemia or thalassaemia
- you take medicine for epilepsy or HIV
More than 10 weeks pregnant? You may be entitled to Healthy Start. Its free tablets contain folic acid, vitamin C and vitamin D, until your baby’s 1st birthday.
In Scotland, Best Start Foods helps instead.
For when to start and stop, see folic acid for women.
Folic acid or folate: which supplement?
Folate is vitamin B9 as it comes in food. Folic acid is the man-made form, used in tablets and fortified cereals.
The pregnancy advice rests on folic acid. A Cochrane review of 5 trials covered 6,708 births. Babies whose mothers took daily folic acid had about a third as many neural tube defects as those whose mothers took no folic acid.
Some supplements use methylfolate (5-MTHF) instead. A 2024 review found a lack of clinical studies on whether it prevents neural tube defects. It said such studies were urgently needed.
Think of two seatbelts. The new one may work just as well, but only one has been crash-tested. For pregnancy, pick the tested one: folic acid.
Not planning a pregnancy? Most people don’t need either form unless a doctor finds you low.
Told you carry an MTHFR gene change? See MTHFR and your folate levels.
Can you take too much folic acid?
Yes. The NHS says 1 mg or less a day is unlikely to cause any harm.
- 1 mg or belowNHS: unlikely to cause harm.
- Above 1 to just under 5 mgOver 1 mg can mask low B12.
- 5 mg or above5 mg: short term, on a GP’s advice. Can mask low B12 too.
Sources: NHS vitamin B; NHS pregnancy
That vitamin is B12. Above 1 mg, folic acid can mask the signs of low vitamin B12. If low B12 isn’t spotted and treated, it can eventually damage the nervous system.
Older people are most at risk, because B12 gets harder to absorb as you age.
It’s like painting over a damp patch: the wall looks fine while the damp spreads.
That’s why your GP checks your B12 first before prescribing folic acid. So keep to 1 mg a day or less, unless a GP prescribes more.
Count every product. One extra folic acid tablet is unlikely to cause problems, but too many multivitamins can be dangerous. See signs of low B12 and high folate levels.
How to take folic acid tablets
How to take folic acid tablets
- Swallow tablets whole with a glass of water.
- Missed a dose? Take it when you remember, then the next one at the usual time. Never take 2 doses to make up.
- Avoid or limit alcohol, which can affect how well folic acid works.
- Keep to 1 mg a day or less, unless a GP prescribes more.
- Tell your doctor about any other medicines, herbal remedies or supplements you take.
- Pregnant? Check with a doctor or pharmacist before taking a multivitamin with folic acid.
Sources: NHS folic acid; NHS vitamin B
Side effects can include bloating, wind, feeling sick and loss of appetite. Speak to a doctor or pharmacist if they bother you or don’t go away.
Folic acid may not suit you if you’ve had an allergic reaction to it, or have cancer. The same goes for a coronary stent, a small mesh tube in a heart artery.
It may not suit you with B12 deficiency anaemia either. Nor with pernicious anaemia, where the immune system attacks the body’s healthy cells.
It may not mix with some epilepsy medicines and antibiotics. Others include aspirin, lithium for mental health, and sulfasalazine for bowel and joint conditions.
Never stop or change a prescribed medicine without your prescriber. Wondering about a daily multivitamin instead? See do I need a multivitamin.
When to speak to a GP
Book an appointment if:
- You’re planning a pregnancy and any of the 5 mg reasons apply. A GP can prescribe the higher dose.
- You feel weak or tired, short of breath or have headaches, palpitations (a pounding, fluttering or uneven heartbeat) or a sore, red tongue, sometimes with mouth ulcers. These can be signs of B12 or folate deficiency anaemia.
- You notice indigestion, loss of appetite, diarrhoea, problems with your vision, or problems with memory, understanding and judgement. These can be signs too. So can numbness, pins and needles, muscle weakness or problems with balance.
- You have B12 deficiency anaemia, pernicious anaemia, a coronary stent or cancer, and want to take folic acid.
- Side effects bother you or don’t go away. A doctor or pharmacist can help.
Call 111 if you’ve swallowed more than your prescribed dose, or more multivitamins than the label says. Call 111 too if you think you’re having a serious side effect. Signs include a swollen face, throat or tongue, a raised, itchy rash and difficulty breathing.
Had a low result already? See low folate levels.