Vitamin B6 in Pregnancy: Dose Limits and Morning Sickness

It's 3am, you're queasy, and the same advice keeps turning up: try vitamin B6. It's on forums, in pregnancy apps and on the shelf at the chemist. So does it work, how much can you take, and is it fine to add it to the vitamins you already take?

Here's the short version. The NHS says to keep vitamin B6 supplements to 10 mg a day unless a doctor advises otherwise. UK guidance doesn't recommend B6 on its own for morning sickness, because the evidence is limited and inconsistent. What UK doctors can prescribe is different, and it matters more than anything on the supplement aisle.

This guide covers what B6 does, what the research and the guidelines say about morning sickness, how to add up B6 across your labels, and when queasiness stops being routine. If you're planning a pregnancy with PMOS (PCOS), it applies to you too. (A quick note on names: PCOS has been renamed PMOS, and we use both here while the change settles in. Here is what it means.)

It's not a magic fix list, and your body is allowed to feel awful without you having to buy something. Evidence last checked: 13 October 2026. Guidance changes, so use the NHS pages linked below for the latest.

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Pale oak kitchen table with dry toast, a glass of water with lemon, a banana, a bowl of oats and sliced ginger, the kind of foods people reach for with pregnancy nausea

In this guide:

What Does Vitamin B6 Do, and How Much Do You Need?

In short: Adult women need about 1.2 mg of vitamin B6 a day, and the NHS says most people can get that from a varied diet, not supplements.

Vitamin B6 (pyridoxine) is a water-soluble vitamin. It contributes to normal protein and glycogen metabolism, the normal function of the nervous system, and the reduction of tiredness and fatigue.

The NHS puts the amount at about 1.2 mg a day for adult women and 1.4 mg for men. It says you should be able to get that from your diet, and that bacteria in your bowel make some too [1]. The NHS page doesn't give a separate figure for pregnancy. If you're worried your intake is low, that's a question for your midwife or GP, not a reason to reach for a high-dose tablet.

The NHS lists these good sources [1]:

  • Meat and fish: pork, poultry such as chicken or turkey, and some fish.
  • Plant foods: peanuts, soya beans, wheatgerm and oats.
  • Everyday foods: bananas, milk and some fortified breakfast cereals.

A word on liver. It's rich in many vitamins, but the NHS says to avoid liver and liver products in pregnancy because of the vitamin A they contain [2]. Leave it off the plate. The foods above cover your B6.

Bananas, oats and milk are all on that list, and they happen to be the bland foods many people with morning sickness find easiest to face. No special product required.

Does Vitamin B6 Help With Morning Sickness?

In short: The evidence is limited. UK guidance doesn't recommend vitamin B6 on its own, and the NHS morning sickness page doesn't mention it.

First, the scale of it. Nausea and vomiting in pregnancy affects up to 90% of pregnancies, and hyperemesis gravidarum, the severe form, affects roughly 0.3% to 3.6% [3]. The NHS links it to hormonal changes in the first 12 weeks and says it usually clears up by weeks 16 to 20 [4]. You're not imagining it, and you're not being dramatic.

Now the evidence on B6 itself. Here is what the main sources say:

Source What it says about vitamin B6
RCOG Green-top Guideline 69 (2024) Notes a lack of consistent evidence that pyridoxine is an effective therapy for nausea and vomiting in pregnancy. In one placebo-controlled trial of 46 women with hyperemesis, adding B6 to standard care did not improve nausea, vomiting or hospital readmission [3].
Cochrane review (2015, 41 trials, 5,449 women) Found only limited trial evidence for B6 in mild or moderate nausea and vomiting. The authors said there is a lack of high-quality evidence for any particular intervention, and that this does not mean the interventions are ineffective [5].
NHS morning sickness page Doesn't mention B6. It suggests lifestyle changes first, then a short-term anti-sickness medicine from your GP if those don't help [4].

Put plainly: B6 might help some people with mild nausea, but nobody has proved it, and the people who write the UK guidelines don't treat it as a first step. That's not the same as "it doesn't work". It means "we can't say".

So why does B6 keep coming up? Partly because it's an ingredient in a prescribed anti-sickness tablet (next section). Partly because it's cheap, easy to buy and feels like doing something when you feel dreadful. That last bit is understandable. It's also how people end up with B6 from four different products without realising.

What Is the Prescribed Tablet With Vitamin B6 in It?

In short: Doxylamine with B6 (Xonvea) is a UK prescription medicine for morning sickness that hasn't improved with diet and lifestyle changes.

This is the bit that gets lost online. In the UK, one licensed medicine for nausea and vomiting in pregnancy combines doxylamine, an antihistamine, with vitamin B6. It's called Xonvea, and it's for adults who haven't responded to lifestyle and diet changes [6].

Each tablet contains 10 mg of doxylamine succinate and 10 mg of pyridoxine. The licensed dose starts at two tablets at bedtime and can go up to four a day, taken daily rather than as needed [6]. That's up to 40 mg of pyridoxine hydrochloride a day. It's the reason the NHS's 10 mg limit comes with the words "unless advised by a doctor". A prescriber has weighed the benefit and checked it suits you. You're not meant to copy the dose from a shelf of vitamins.

How well does it work? A Drug and Therapeutics Bulletin review reported small but statistically significant improvements over placebo, and said it wasn't aware of high-quality evidence that the combination works better than other anti-sickness medicines. Dizziness, drowsiness, dry mouth and fatigue are among the listed side effects [7]. The product information cites two meta-analyses covering more than 168,000 patients, about 18,000 of them with first-trimester exposure, that reported no malformative or fetal or neonatal toxicity [6].

RCOG guidance lists antihistamines, phenothiazines and doxylamine with pyridoxine as first-line options, to be prescribed when needed for nausea and vomiting in pregnancy and hyperemesis (Grade A evidence). Ondansetron is second-line [3]. So the UK ladder runs: lifestyle changes, then a prescribed anti-sickness medicine. A stand-alone B6 tablet isn't on it.

If you're struggling, call your GP or midwife. You don't have to earn a prescription by suffering for longer.

How Much Vitamin B6 Is Too Much in Pregnancy?

In short: The NHS says no more than 10 mg of B6 a day in supplements unless a doctor advises. At 200 mg or more, nerve damage becomes a risk.

B6 from food isn't the issue. Supplements are, because the amounts add up fast. Here is what the NHS says about daily B6 from supplements [1]:

Daily B6 from supplements What the NHS says
10 mg or less The most the NHS says to take as a supplement without a doctor's advice.
More than 10 mg, up to 200 mg The effect is unclear. There isn't enough evidence to say how long these amounts can be taken without harm.
200 mg or more Can lead to a loss of feeling in the arms and legs (peripheral neuropathy). It usually improves after stopping, but in a few cases, particularly with large amounts taken for more than a few months, it can be permanent.
Amounts a doctor prescribes Medically supervised. For example, the prescribed combination tablet can supply up to 40 mg a day, as pyridoxine hydrochloride [6].

The Cochrane review of B6 supplementation in pregnancy also noted that high doses can cause harm, including numbness and difficulty walking [8]. And it's worth knowing the NHS vitamin pages we used don't set a different limit for pregnancy, so if you're pregnant and think you might be above 10 mg, ask your midwife, GP or pharmacist rather than guessing.

If you've been taking more than 10 mg a day on your own, don't panic and don't stop any medicine a doctor prescribed. Stop the extra over-the-counter product, and tell your midwife, GP or pharmacist, especially if you've noticed tingling or numbness in your hands or feet.

How Do You Add Up Vitamin B6 Across Your Labels?

In short: List everything you take, find B6 on each label, add the milligrams. If the total tops 10 mg a day, ask your midwife or GP.

Stacking is how most people end up over the limit. A pregnancy multivitamin, a "morning sickness" product, a magnesium or sleep drink, an energy powder and a stand-alone B6 tablet can each look sensible, and none of them tells you what the others contain. Here's the five-minute fix:

  • Lay it all out. Every tablet, capsule, powder, drink and tea you use regularly, including anything marketed for sleep, energy or nausea.
  • Find the B6 line. Look for vitamin B6, pyridoxine, pyridoxine hydrochloride or pyridoxal 5'-phosphate. They're all vitamin B6, just different forms.
  • Use the milligrams. Some labels show B6 as a percentage of the nutrient reference value instead. Look for the mg figure, and check whether it's per capsule or per full daily serving.
  • Add it up. Here's an illustration only: a multivitamin with 10 mg, a stand-alone tablet with 25 mg and a sleep drink with 3 mg come to 38 mg a day, nearly four times the NHS limit.
  • Ask. If your total is above 10 mg and no doctor has told you to take it, speak to your midwife, GP or pharmacist.

The same check works if you're trying to conceive, and it takes less time than the scroll that sent you here.

Infographic titled Vitamin B6 in Pregnancy: The UK Numbers, with five cards showing 1.2 mg a day needed, 10 mg or less as the NHS supplement limit, 10 to 200 mg effect unclear, 200 mg or more nerve risk, and a reminder to check every label

Should Every Pregnant Woman Take a Vitamin B6 Supplement?

In short: No. A Cochrane review found no evidence that routine B6 supplements in pregnancy help, and the NHS asks for folic acid and vitamin D instead.

No. A Cochrane review of four trials with 1,646 pregnant women found no evidence from randomised trials that routine B6 supplementation is beneficial. The trials ran between 1960 and 1983, didn't measure important outcomes in newborns and didn't study side effects. So the honest summary is "we don't know much", not "it's proven harmless" [8].

What the NHS does ask you to take [2]:

  • Folic acid: 400 micrograms a day, starting before pregnancy and continuing until week 12. Some people need 5 mg on prescription from a GP.
  • Vitamin D: 10 micrograms a day from September to March.
  • The label check: if you take a multivitamin for your folic acid, choose one without vitamin A (retinol), and always check the label.

Folic acid versus folate is its own rabbit hole, and we've covered it in Folate vs Folic Acid: What's the Real Difference?. Vitamin D has its own guide too: Vitamin D and Your Hormones.

That's the boring answer, and it's the right one: take what the NHS names, eat a varied diet, and treat anything else as a conversation with your midwife.

What Does the NHS Suggest for Morning Sickness?

In short: Rest, small plain meals, cold foods, regular sips of fluid and ginger. If those don't help, a GP can prescribe an anti-sickness medicine.

The NHS says there's no single treatment that works for everyone. Its list is simple, and it's worth trying before you spend money [4]:

  • Rest. Tiredness can make nausea worse.
  • Avoid triggers. Steer clear of foods or smells that make you feel sick.
  • Eat something before you get up. Dry toast or a plain biscuit in the morning.
  • Small, frequent, plain meals. Higher in carbohydrate and lower in fat.
  • Go cold. Cold foods rather than hot ones if cooking smells set you off.
  • Sip fluids. Little and often, which may help prevent vomiting.
  • Ginger. Foods or drinks containing ginger may help. The NHS says there is some evidence, and to check with a pharmacist before taking ginger supplements in pregnancy.
  • Acupressure. A wristband or pressure on the wrist may help, though the NHS describes the evidence as limited.

The Cochrane review agrees on the theme: ginger products may help, but the evidence is limited and inconsistent, and acupressure evidence is limited too [5]. For severe vomiting, RCOG goes further. A survey of 512 women with hyperemesis found little or no benefit from ginger, and adverse effects or worse symptoms in 54%. RCOG's good practice point is that clinicians shouldn't suggest ginger for hyperemesis, because it may delay effective treatment [3].

None of this is glamorous. It is the list the NHS gives, and most of it is free.

When Is Morning Sickness Something More Serious?

In short: Contact a midwife, GP or 111 if you can't keep food or fluids down for 24 hours or your urine is dark. Hyperemesis can be serious.

Hyperemesis gravidarum is a severe form of pregnancy sickness. The NHS warns that it can be serious, may cause dehydration or malnutrition, and can need specialist treatment, sometimes in hospital [4]. Contact a midwife, your GP or NHS 111 if you're vomiting and have any of these [4]:

  • Urine that's dark in colour, or you haven't passed urine for more than 8 hours.
  • You can't keep food or fluids down for 24 hours.
  • Dizziness or weakness when you stand up.
  • Tummy pain or a high temperature.
  • You're vomiting blood.
  • You're losing weight.

RCOG guidance describes care that can include day care and, if needed, a hospital stay for dehydration or weight loss despite treatment [3]. Pregnancy Sickness Support is a UK charity offering information and peer support for people with severe pregnancy sickness.

If it's stopping you eating and drinking, it isn't "just morning sickness". Say so plainly and ask for treatment. Don't wait to see whether extra B6 helps first.

What About Vitamin B6 When You're Trying to Conceive?

In short: We found no UK guidance telling you to take extra B6 before pregnancy. Folic acid is the one the NHS asks you to start before conceiving.

If you're planning a pregnancy, especially with PMOS (PCOS) or irregular cycles, the supplement noise gets louder before conception than it does in pregnancy. The NHS asks for 400 micrograms of folic acid a day before pregnancy and until week 12 [2]. We couldn't find UK guidance recommending extra B6 at this stage, so the NHS 10 mg a day limit still applies to anything you take [1].

Our guides on fertility habits with PMOS (PCOS) and vitamin B6 and PMOS (PCOS) cover the wider picture. In the UK, the usual advice is to talk to your GP after a year of trying without success, or sooner if you're 36 or over or your periods are irregular. You don't have to wait if something feels off.

In the interest of disclosure, we make supplements. The label on MyOva Pregnancy lists vitamin B6 (10 mg, as pyridoxal 5'-phosphate) across its four-capsule daily serving. Check any pack, ours included, against your total, and speak to your midwife or GP before starting a new supplement.

Frequently Asked Questions

Can I take vitamin B6 while pregnant?

B6 from food is part of a normal diet. For supplements, the NHS says not to take more than 10 mg a day unless a doctor advises. Check with your midwife or GP before adding a stand-alone B6 tablet [1].

How much vitamin B6 should I take for morning sickness?

There's no UK recommended dose for B6 on its own. The prescribed combination tablet (doxylamine 10 mg with B6 10 mg) starts at two tablets at bedtime, up to four a day, and only on medical advice [6].

Does vitamin B6 stop morning sickness?

Not reliably. A Cochrane review found only limited trial evidence, and RCOG notes a lack of consistent evidence that pyridoxine works as a stand-alone treatment [5, 3].

Is ginger better than vitamin B6 for morning sickness?

Neither is proven. The NHS says there's some evidence for ginger and advises checking with a pharmacist before ginger supplements. RCOG says clinicians shouldn't suggest ginger for hyperemesis [4, 3].

Can too much vitamin B6 be harmful?

Yes. The NHS says 200 mg or more a day can lead to loss of feeling in the arms and legs, which is usually reversible but sometimes permanent. The effect of 10 mg to 200 mg a day is unclear [1].

Which foods are high in vitamin B6?

Pork, chicken, turkey, some fish, peanuts, soya beans, wheatgerm, oats, bananas, milk and some fortified cereals. Avoid liver in pregnancy [1, 2].

The Bottom Line

Vitamin B6 isn't a villain or a hero. It's a vitamin you need in small amounts, found in everyday food, and the NHS draws a clear line for supplements: 10 mg a day unless a doctor advises. For morning sickness, the evidence for B6 alone is thin, and the UK route is lifestyle changes first and then a prescribed medicine, one of which happens to contain B6.

This is what I wish someone had told me: you don't have to put up with relentless sickness to prove you deserve help, and you don't have to build a stack of tablets to cope. Your body is trying to tell you something, and when it says it can't keep water down, that's a prompt to call someone, not to buy something.

Related Reading

This article is for educational purposes only and does not constitute medical advice. Guidance details are accurate to the sources cited at the time of writing and may change. MyOva products are food supplements, not medicines, and are not intended to diagnose, treat, cure or prevent any disease. Food supplements should not replace a varied diet. If you are pregnant, planning a pregnancy or taking any medication, speak to your midwife, GP or pharmacist before starting or changing any supplement.

References

  1. NHS. Vitamins and minerals: B vitamins and folic acid (vitamin B6 section). https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/
  2. NHS. Vitamins, supplements and nutrition in pregnancy. https://www.nhs.uk/pregnancy/keeping-well/vitamins-supplements-and-nutrition/
  3. Royal College of Obstetricians and Gynaecologists. The management of nausea and vomiting in pregnancy and hyperemesis gravidarum (Green-top Guideline No. 69). BJOG. 2024;131(7):e1-e30.
  4. NHS. Vomiting and morning sickness in pregnancy. https://www.nhs.uk/pregnancy/related-conditions/common-symptoms/vomiting-and-morning-sickness/
  5. Matthews A, Haas DM, O'Mathúna DP, Dowswell T. Interventions for nausea and vomiting in early pregnancy. Cochrane Database Syst Rev. 2015;CD007575.
  6. Exeltis UK Ltd. Xonvea 10 mg/10 mg gastro-resistant tablets: summary of product characteristics. electronic medicines compendium. https://www.medicines.org.uk/emc/product/14892/smpc/print
  7. Drug and Therapeutics Bulletin. Review of doxylamine/pyridoxine (Xonvea) for nausea and vomiting in pregnancy. Drug Ther Bull. 2019;57(3):38. https://dtb.bmj.com/content/57/3/38
  8. Salam RA, Zuberi NF, Bhutta ZA. Pyridoxine (vitamin B6) supplementation during pregnancy or labour for maternal and neonatal outcomes. Cochrane Database Syst Rev. 2015;(6):CD000179.
Leila Martyn

Leila Martyn

Leila is the founder of MyOva, a UK-based hormonal health brand for women with PMOS (PCOS), endometriosis, perimenopause, PMDD and fertility challenges. Drawing on lived experience and scientific research, she shares evidence-based guidance to help women feel informed about their hormones and cycles.

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