Vitamin B6
A water-soluble vitamin, long taken for the nausea and sickness of pregnancy.
- Morning sickness
- Mood and stress
- Sleep and dreams
- Pregnancy and birth
- Homocysteine
- Nerve symptoms
A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.
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On this page
What is vitamin B6?
Vitamin B6 is a water-soluble vitamin, present naturally in many foods and sold in a great many supplements. It comes in three natural forms - pyridoxine, pyridoxal and pyridoxamine - and the body works with it as pyridoxal 5’-phosphate, a helper molecule for more than 150 chemical reactions: the handling of carbohydrates, fats, amino acids and DNA, and the making of the messengers nerves signal with. Mild shortfalls are described as a widespread concern worldwide. On a shelf here it appears as pyridoxine hydrochloride or as that active form, sold as P-5-P.
Why do people take vitamin B6?
Morning sickness
The thinking. Nausea and sickness are among the commonest complaints of pregnancy, and no single option for them is settled, which is how vitamin B6 came to be so widely used. For many people it is the reason they buy B6 at all.
What research has found. A review drew together 18 studies and measured sickness on two standard scales. Nausea scores came out lower both where pyridoxine was taken on its own and where it was paired with another active ingredient. Research here is still young: a few studies so far, mostly pointing the same way.
Mood and stress
The thinking. The body uses B6 to make GABA, the messenger that quietens nerve signalling, and the vitamin sits in the chemistry that tips the balance from excitation towards inhibition. That is the thinking behind taking it when life feels relentless, often beside magnesium.
What research has found. One trial gave 478 young adults a high dose for a month and found lower self-reported anxiety. In stressed adults who were low in magnesium, adding 30 mg of B6 to magnesium moved stress, depression and anxiety scores no further than magnesium alone, though the most stressed did better on it. Two trials of B6 for irritability caused by an epilepsy medicine disagreed. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
Sleep and dreams
The thinking. Taking B6 before bed has a long anecdotal reputation for making dreams easier to remember, and that is what drew researchers to it. Others take it with magnesium at night for restless legs, one of the commonest sleep complaints.
What research has found. A hundred adults took 240 mg before bed for five nights: they recalled more dream content, though dreams were no more vivid, strange or colourful and sleep itself was unchanged. In 75 adults with restless legs, B6 or magnesium left symptom and sleep scores no different at one month and better by the second. The studies disagree, so this is unsettled: dose, duration and who took part all seem to shift the result.
Pregnancy and birth
The thinking. Some women take B6 right through pregnancy rather than only for sickness. The interest came from earlier, non-randomised studies that linked it with higher Apgar scores, heavier babies and fewer cases of pre-eclampsia.
What research has found. A review of four randomised trials in 1,646 women found less dental decay among those given capsules or lozenges, and no difference in eclampsia, pre-eclampsia or Apgar scores. One small trial of 33 women found slightly lower average birthweights. The reviewers rated the evidence low quality. Results here go both ways, which usually means the dose, the length of a trial or the group taking part makes the difference.
Homocysteine
The thinking. B6 is one of the vitamins in one-carbon metabolism, the chemistry that handles homocysteine, an amino acid in the blood described as a possible risk factor for furring of the arteries. People take it with folate and B12 with that in mind.
What research has found. One trial followed 117 middle-aged men drinking white wine daily for a month. Homocysteine fell in the men given folic acid or betaine; in those given B6 or B12 it did not shift to any statistically significant degree. Few studies have measured this yet, so there is little to go on either way.
Nerve symptoms
The thinking. Tingling and numbness send people to the B vitamins, and B6 has a part in how the nervous system develops and works. Both being short of B6 and taking a lot of it have been described as risk factors for nerve trouble.
What research has found. A review of twenty articles found that higher B6 levels, which usually follow the taking of supplements, can go with a sensory nerve problem, and that people reported symptoms easing after they stopped. It found no study of B6 given on its own for nerve symptoms, only in combination, and no harm at permitted daily amounts. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
What does vitamin B6 do in the body?
B6 is a helper rather than a fuel. In its active form, pyridoxal 5’-phosphate, it sits inside enzymes and lets them do their chemistry: more than 150 reactions depend on it, spanning carbohydrates, fats, amino acids, DNA and the signals cells send one another. Among them are the reactions that build the messengers nerves use.
That single role explains the range. The same helper turns up in the chemistry that quietens nerve signalling, in one-carbon metabolism where homocysteine is handled, and in the kynurenine and transsulfuration pathways that run alongside inflammation. B6 also acts as an antioxidant and lowers advanced glycation end-products. Blood levels are usually read from plasma PLP, and read with care: inflammation, kidney function and low albumin all pull the number about.
What do people say about taking vitamin B6?
These are anecdotes people have shared, not evidence.
What people like
- Very commonly, the sickness easing rather than stopping: people describe being able to function again, though still being sick sometimes.
- Often it is noticed within a day or two, which people find unusually quick for a supplement.
- Several say the clearest proof came from running out: sickness returned within days, then settled again once they restarted.
- A minority take it for dreams instead, and report remembering far more of them, in more detail, the morning after.
Common complaints
- In every sickness thread a few say it did nothing for them, while others there call it the only thing that worked.
- Some describe dizziness, headaches, a metallic taste, or tingling in the mouth, ankles and feet, usually within a week of starting.
- Tingling and numbness at high doses is what worries people most, with stories of nerve damage passed around the threads.
- Very commonly, people say they cannot work out what dose is safe, quoting figures at each other that range from 10 mg to 100 mg.
How people take it
- The doses described run from about 10 mg to 100 mg a day, and people commonly split them rather than taking one large tablet.
- Very commonly a dose last thing at night is singled out as the important one; those taking it for dreams also take it before bed.
- Some prefer the active P-5-P form, or liquid drops, when tablets are hard to keep down.
- Often it sits beside another B vitamin or magnesium, and a good number check with a midwife or GP first.
Read from these public discussions:
- Vitamin B6 for morning sickness? Any success? (Mumsnet, 2011)
- Vit B6, dizziness and other side effects (Mumsnet, 2012)
- Vitamin b6 for morning sickness (Mumsnet, 2018)
- B6 for nausea?? (Mumsnet, 2024)
- Vitamin B6 dangerous during pregnancy?? (Mumsnet, 2025)
- Too many Lucid Dreams? (AnandTech forums, 2007)
What forms of vitamin B6 are there?
| Form | What’s different | Per serving, on products we list |
|---|---|---|
| Pyridoxine HCl | The salt of pyridoxine, one of the vitamin’s three natural forms. | 50 mg |
| P-5-P (active form) | Pyridoxal 5’-phosphate, the form the vitamin is put to work as inside the body. | not in our price tables yet |
What else is worth knowing about vitamin B6?
- Labels give the vitamin B6 per serving, and a serving may be more than one tablet; it is sold as pyridoxine hydrochloride or as the active P-5-P.
- The amounts in the trials varied enormously: 30 to 40 mg a day in the stress and restless-legs studies, 240 mg before bed for five nights in the dream study.
- Higher B6 levels, which usually follow the taking of supplements, have been described as a risk factor for sensory nerve symptoms; the same review found no harm at permitted daily amounts.
- In the stress trial, 12.1 per cent of those on magnesium with B6 reported a side effect thought to be treatment-related, against 17.4 per cent on magnesium alone.
If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.
The research behind this page (16 studies)
- The effects of pyridoxine (vitamin B6) supplementation in nausea and vomiting during pregnancy: a systematic review and meta-analysis. (2023, meta-analysis)
- Current evidence for adjunct pyridoxine (vitamin B6) for the treatment of behavioral adverse effects associated with levetiracetam: A systematic review. (2023, systematic review)
- High-dose Vitamin B6 supplementation reduces anxiety and strengthens visual surround suppression. (2022, randomised trial)
- Effect of magnesium and vitamin B6 supplementation on mental health and quality of life in stressed healthy adults: Post-hoc analysis of a randomised controlled trial. (2021, randomised trial)
- Superiority of magnesium and vitamin B6 over magnesium alone on severe stress in healthy adults with low magnesemia: A randomized, single-blind clinical trial. (2018, randomised trial)
- Therapeutic effects of magnesium and vitamin B6 in alleviating the symptoms of restless legs syndrome: a randomized controlled clinical trial. (2022, randomised trial)
- Effects of Vitamin B6 (Pyridoxine) and a B Complex Preparation on Dreaming and Sleep. (2018, randomised trial)
- Pyridoxine (vitamin B6) supplementation during pregnancy or labour for maternal and neonatal outcomes. (2015, meta-analysis)
- Effect of Folic Acid, Betaine, Vitamin B₆, and Vitamin B12 on Homocysteine and Dimethylglycine Levels in Middle-Aged Men Drinking White Wine. (2016, randomised trial)
- The Role of Vitamin B6 in Peripheral Neuropathy: A Systematic Review. (2023, systematic review)
- Vitamin B₆ and Its Role in Cell Metabolism and Physiology. (2018, review)
- Inflammation, vitamin B6 and related pathways. (2017, review)
- Vitamin B6 in Health and Disease. (2021, review)
- Direct and Functional Biomarkers of Vitamin B6 Status. (2015, review)
- Vitamin B6 and Diabetes: Relationship and Molecular Mechanisms. (2020, review)
- Relationship of Low Vitamin B6 Status with Sarcopenia, Frailty, and Mortality: A Narrative Review. (2024, review)
How much does vitamin B6 cost?
That depends on the form and the pack, so we work out the price of the same dose of every vitamin B6 product we can find and rank them.