Why Does B6 Help with Nausea? The Nutritional Science Behind a Common Remedy

October 8, 2025 •

4 min read

Approximately 70-80% of pregnant women experience some form of morning sickness, making remedies a topic of high interest. For many, understanding why B6 helps with nausea offers a safe, evidence-based approach to managing their symptoms.

Quick Summary

Vitamin B6, or pyridoxine, helps reduce nausea by influencing key neurotransmitters like serotonin and GABA in the brain and gut, which regulate the body's nausea response. Its active form, pyridoxal 5'-phosphate (PLP), is believed to be responsible for this antiemetic effect.

Key Points

Neurotransmitter Regulation: Vitamin B6 acts as a critical cofactor in the synthesis of neurotransmitters like serotonin and GABA, which are key to controlling the body's nausea response.
Active Coenzyme Form: The body converts pyridoxine (B6) into its active coenzyme form, pyridoxal 5'-phosphate (PLP), which is believed to be the primary antiemetic agent.
Hormonal Influence: In pregnancy, B6 may help counteract hormonal imbalances, such as high estrogen levels, that can trigger morning sickness.
Effective for Mild to Moderate Nausea: Studies show B6 can be effective at reducing the severity of mild-to-moderate nausea, but it is less reliable for controlling severe vomiting.
Safe and Tolerable Remedy: For many, B6 is a safe and well-tolerated option, especially when used in combination with doxylamine for pregnancy-related nausea.
Available Through Diet and Supplements: Individuals can increase their B6 intake by eating foods like fish, bananas, and whole grains, or through supplementation under medical guidance.

The Science Behind B6 and Nausea

Nausea is a complex sensation mediated by a network of neurological pathways involving both the brain and the gastrointestinal tract. Vitamin B6, also known as pyridoxine, influences these pathways to help alleviate feelings of queasiness. While the exact mechanism is not fully understood, research points to several key processes where B6 plays a critical role.

The Neurotransmitter Connection

One of the most well-documented mechanisms involves B6's function as a cofactor in the synthesis of several important neurotransmitters. These brain chemicals transmit signals throughout the nervous system, and their balance is crucial for regulating the body's nausea reflex. By assisting in the production of these chemicals, B6 helps to normalize these signals.

Serotonin: This neurotransmitter regulates mood, but it also plays a significant role in gut function. Imbalances in serotonin levels can trigger nausea and vomiting. B6 is essential for serotonin synthesis, and its supplementation can help stabilize levels.
Dopamine: Involved in the brain's reward and motor systems, dopamine can also influence the chemoreceptor trigger zone (CTZ), a region in the brain that initiates vomiting. By regulating dopamine levels, B6 can help control these impulses.
Gamma-aminobutyric acid (GABA): As an inhibitory neurotransmitter, GABA helps to calm overactive nerve signals. B6 is involved in GABA synthesis, and a deficiency has been hypothesized to contribute to nausea and vomiting in pregnancy.

The Active Form: Pyridoxal 5'-Phosphate (PLP)

It is important to note that pyridoxine is not the form of the vitamin that directly produces the antiemetic effect. Instead, it acts as a prodrug. The body must first convert pyridoxine into its active coenzyme form, pyridoxal 5'-phosphate (PLP). Studies have shown a correlation between serum PLP levels and the reduction in morning sickness symptoms. This suggests that the conversion process is key to its efficacy.

Hormonal Fluctuations and Nausea

For many pregnant women, nausea is linked to significant hormonal shifts, particularly the rise in estrogen. One hypothesis suggests that B6 may help mitigate the effects of these hormonal changes by acting as a coenzyme that influences protein receptors involved in regulating nausea. While this area requires further research, it offers another potential explanation for the vitamin's effectiveness during pregnancy.

Who Can Benefit from B6 for Nausea?

While most famously associated with morning sickness, B6 has been studied for its use in other types of nausea as well. Its gentle mechanism makes it a suitable option for various individuals seeking relief.

Pregnancy-related Nausea (NVP): As a first-line treatment, B6 can be a safe option for many expectant mothers. It is often prescribed alone or in combination with doxylamine.
Chemotherapy-Induced Nausea and Vomiting (CINV): Some studies have investigated B6's role in mitigating CINV, especially in pediatric patients, with positive results.
General Queasiness and Motion Sickness: For mild to moderate nausea not caused by a specific disease, B6 can help balance brain signals to provide relief.

Supplementation and Dietary Sources

Before starting any new supplement, it is crucial to consult a healthcare provider, especially during pregnancy. High doses of vitamin B6 can lead to nerve damage and other neurological symptoms, so it is important to follow guidance from a healthcare professional.

It is also possible to increase B6 intake through a balanced diet. Many foods are naturally rich in this essential vitamin, providing a gentle and sustained source for the body.

Foods high in Vitamin B6 include:

Fish (e.g., salmon, tuna)
Poultry (e.g., chicken, turkey)
Potatoes
Bananas
Whole grains and fortified cereals
Nuts and seeds (e.g., sunflower seeds)
Avocados
Spinach

Comparison of Anti-Nausea Remedies


Remedy	Mechanism	Primary Use	Onset of Action	Pros	Cons
Vitamin B6 (Pyridoxine)	Cofactor in neurotransmitter synthesis (serotonin, GABA).	Mild-to-moderate nausea, primarily in pregnancy.	Gradual, often best with consistent use.	Safe, generally well-tolerated, no drowsiness.	May not be effective for severe vomiting.
Doxylamine	H1-receptor antagonist (antihistamine).	Combination therapy with B6 for morning sickness.	Can be faster when combined with B6.	Effective in treating nausea and vomiting.	May cause drowsiness.
Ginger	Inhibits serotonin receptors and has gastrointestinal effects.	Pregnancy-related nausea.	Varies, but can provide quicker relief.	Natural, few side effects.	Can cause heartburn or reflux.
Acupressure	Stimulates nerve fibers to alter nausea signaling.	Various types of nausea (motion, morning sickness).	Immediate, if effective.	Non-pharmacological, no systemic side effects.	Effectiveness varies, may involve placebo effect.

Conclusion

The reason why B6 helps with nausea stems from its essential role as a cofactor in producing key neurotransmitters that regulate the body's nausea reflex. By helping to balance these brain chemicals, especially through its active form PLP, B6 can calm the neural signals that trigger queasiness. This makes it a popular and effective nutritional strategy, particularly for pregnant women and those with other forms of mild-to-moderate nausea. While it may not be a cure-all for severe vomiting, its safety profile and effectiveness in managing nausea make it a well-regarded dietary remedy. Always consult a healthcare professional before beginning supplementation to determine appropriate use and to rule out any underlying conditions.

For more detailed information on vitamin B6, consult reliable health resources like the National Institutes of Health.

Frequently Asked Questions

Vitamin B6 does not work instantly. It typically takes time to have an effect, and consistent use often yields the best results for sustained relief. Consult a healthcare professional for guidance on expected timing.

Yes, vitamin B6 is generally considered safe for pregnant women when used appropriately. It is often a first-line treatment option for morning sickness, but you should always consult your healthcare provider before starting any new supplement.

Consult with your doctor to determine the appropriate way to take B6 for morning sickness, including the right amount and frequency for your specific needs. Do not exceed recommended amounts without medical supervision.

Yes, excessive intake of vitamin B6 can have neurological implications. High levels can lead to nerve damage, numbness, and tingling, so it is important to follow guidance from a healthcare professional regarding appropriate amounts.

B6 is more effective at alleviating the sensation of nausea than it is at controlling episodes of vomiting, especially if the body is trying to expel toxins. It helps balance the signals that trigger queasiness rather than blocking the body's protective reflex.

While it's possible to increase your B6 intake through diet, supplementation may be recommended for managing active nausea, as it can provide a more consistent amount. For general health, a diet rich in B6 foods like fish, bananas, and whole grains is beneficial.

B6 is sometimes used in combination with other medications like doxylamine (Unisom). However, it's essential to consult a healthcare provider to ensure safe use with any other medications you may be taking.