Vitamin B6 is one of the most well-supported natural remedies for nausea, particularly during pregnancy. It’s often the first thing recommended for morning sickness, and clinical trials show it can cut nausea severity by roughly 35% to 40% within four days of regular use. Other B vitamins don’t have the same anti-nausea effect, though a B12 deficiency can cause nausea on its own.
Why B6 Helps With Nausea
Vitamin B6, also called pyridoxine, plays a key role in producing neurotransmitters, the chemical messengers your brain and gut use to communicate. Its active form in the body acts as a helper molecule in dozens of chemical reactions, including the production of serotonin. Since serotonin is heavily involved in regulating the nausea response (your gut actually produces most of your body’s serotonin), B6’s role in that pathway is the most likely explanation for its anti-nausea properties.
That said, researchers haven’t pinpointed the exact mechanism with certainty. What they do know is that it works in controlled trials, and it works well enough that major obstetric guidelines list it as a first-line treatment for pregnancy nausea.
Pregnancy Nausea: The Strongest Evidence
The best-studied use of B6 for nausea is during pregnancy. In randomized controlled trials, 25 mg taken three times a day (75 mg total) was significantly more effective than placebo at reducing both nausea and vomiting. This is the dose most commonly recommended by obstetricians as an initial approach before considering stronger medications.
You won’t feel better instantly. In one trial comparing B6 to ginger for pregnancy nausea, symptom scores dropped modestly after two days, more noticeably after three days, and reached their lowest point by the fourth day of treatment. The pattern was a steady, gradual improvement rather than a quick fix.
When B6 alone isn’t enough, it’s often paired with doxylamine, an antihistamine found in some over-the-counter sleep aids. This combination was widely prescribed in the 1970s under the brand name Bendectin and remains a standard recommendation today. A typical approach is 25 mg of B6 three times daily plus a single 25 mg doxylamine tablet at night. The combination tends to control nausea more effectively than either ingredient on its own.
Does B6 Help With Other Types of Nausea?
Outside of pregnancy, the evidence is much thinner. One small study on ovarian cancer patients undergoing chemotherapy found that B6 injected at an acupuncture point, combined with acupuncture itself, reduced vomiting episodes more effectively than either treatment alone. But B6 by itself didn’t perform nearly as well in that study, and it’s not part of standard anti-nausea protocols for chemotherapy.
For motion sickness, the CDC notes that the evidence supporting vitamins and supplements is weak and contradictory. B6 hasn’t been shown to reliably prevent car sickness, seasickness, or similar conditions.
For hangover nausea, one older study found that a high dose of a B6-related compound (1,200 mg of pyritinol) reduced the total number of hangover symptoms reported, but it didn’t measure how severe those symptoms were. Other studies using B-vitamin blends found no meaningful effect on hangover severity or alcohol metabolism. So while the idea of taking B vitamins after drinking is popular, the science doesn’t back it up very well.
B12 Deficiency Can Cause Nausea
While B6 actively fights nausea, B12 enters the picture from the opposite direction. A deficiency in B12 can cause nausea, along with fatigue, tingling in the hands and feet, muscle weakness, and a smooth, tender tongue. This is worth knowing because B12 deficiency is fairly common, especially in older adults, vegetarians, and people with digestive conditions that impair absorption.
If your nausea is persistent and unexplained, and especially if it comes with fatigue or neurological symptoms like numbness, a B12 deficiency could be the underlying cause. Treatment typically involves B12 supplements, either as pills or injections, and nausea resolves as levels return to normal. Some people need ongoing supplementation depending on the reason for the deficiency.
How Much B6 Is Safe
The dosages used in nausea trials (75 mg per day) are well above what you’d get from food alone, but they’re generally considered safe for short-term use. The European Food Safety Authority set an upper limit of 12 mg per day for long-term intake based on the risk of peripheral neuropathy, a condition where high B6 levels damage nerves in your hands and feet, causing numbness and tingling.
This creates a practical tension: the dose that works for nausea (75 mg/day) exceeds the conservative long-term safety limit. For short stretches, like a few weeks of severe morning sickness, most guidelines consider this acceptable. But taking high-dose B6 for months without medical guidance increases the risk of nerve damage. If you’re using B6 for nausea beyond early pregnancy, it’s worth discussing duration with a provider.
B6 Compared to Ginger
Ginger is the other popular natural remedy for nausea, and the two have been studied head to head. In a direct comparison trial for pregnancy nausea, both B6 and ginger produced nearly identical reductions in symptom scores by day four. Neither was clearly superior. This means if one doesn’t work well for you or causes side effects, the other is a reasonable alternative. Some people also use both, though the combination hasn’t been formally studied as a paired treatment.
The practical difference is in how you take them. B6 comes in precise tablet doses, making it easier to control your intake. Ginger varies widely in potency depending on the form: capsules, teas, candies, and fresh ginger root all deliver different amounts of the active compounds.