B vitamins will not remove the causes of stress, but they are among the better-studied nutrients for how stressed people feel. In randomized trials lasting four weeks to three months, adults taking a daily B-complex or a multivitamin rich in B vitamins reported modestly lower perceived stress than those taking a placebo. The effect is small, and it builds on a diet that already supplies these vitamins rather than replacing it.
Key Takeaways
- A 2019 meta-analysis of 16 randomized trials (2,015 participants) found that supplements with at least three B vitamins produced a small reduction in self-rated stress.
- A 2013 meta-analysis of eight multivitamin trials in healthy adults also found lower perceived stress, and formulas higher in B vitamins appeared to do more.
- In a 90-day trial in 60 stressed workers, a high-dose B-complex lowered reported personal strain compared with placebo.
- B6, folate, B12 and pantothenic acid are involved in making neurotransmitters and other signaling molecules the body uses under stress.
- People with low B vitamin intake or status appear most likely to notice a difference; food should still supply most of your B vitamins.
- Stay under the upper limits for vitamin B6 (100 mg a day), niacin (35 mg a day from supplements) and folic acid (1,000 mcg a day).
Evidence grade: Moderate. Two meta-analyses of randomized, placebo-controlled trials point the same way on perceived stress, but the effect is small, most trials were short, and several were run by researchers with supplement-industry funding.
What B Vitamins Do in the Body
There are eight B vitamins: thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), vitamin B6, biotin (B7), folate (B9) and vitamin B12. All are water soluble, and they work as coenzymes in hundreds of reactions that turn food into energy, build DNA, and make the chemical messengers the brain and nerves rely on.
A few of these roles matter most for the stress question:
- Vitamin B6 is involved in more than 100 enzyme reactions, including the biosynthesis of neurotransmitters and keeping homocysteine at normal levels.
- Folate and vitamin B12 work together to convert homocysteine to methionine, which the body uses to make S-adenosylmethionine, a key methyl donor.
- Pantothenic acid is used to make coenzyme A, which is involved in the synthesis of several neurotransmitters and steroid hormones.
Because the B vitamins depend on one another, researchers such as David Kennedy have argued that studies should look at the whole group rather than one or two vitamins in isolation. For a closer look at how B6, folate and B12 relate to brain chemistry, see our guide to B vitamins and their role in mood regulation.
What the Studies Show About B Vitamins and Stress
The 2019 meta-analysis
The most complete review to date, by Young and colleagues at Swinburne University, pooled randomized controlled trials that gave adults a daily supplement containing at least three B vitamins for four weeks or longer. It included 18 papers from 16 trials with 2,015 participants. Six of the ten studies that measured stress found a benefit, and the pooled analysis showed a small but statistically significant reduction in stress scores (958 participants; standardized mean difference 0.23).
The same review did not find a clear effect on anxiety scores, and the effect on low-mood scores did not reach statistical significance. In other words, stress was the one facet of mood where the evidence lined up.
The 2013 multivitamin meta-analysis
An earlier meta-analysis by Long and Benton combined eight placebo-controlled trials of multivitamin and mineral supplements taken for at least 28 days by people from the general population. Supplementation reduced perceived stress, as well as fatigue and confusion. The authors noted that supplements containing high doses of B vitamins may be more effective for mood than lower-dose formulas.
The 90-day work stress trial
In a double-blind trial published in Human Psychopharmacology in 2011, Stough and colleagues gave 60 adults with chronic work stress one of two high-dose B-complex formulas or a placebo for three months. After accounting for personality and job demands, the B-complex groups reported significantly lower personal strain and less confusion and dejected mood at 12 weeks. Other measures of mood and anxiety did not change.
How big is the effect?
A standardized mean difference of about 0.2 to 0.35 is considered small. That is consistent with what most people should expect: a B-complex may take a little of the edge off how stressed you feel, especially if your intake was low, but it is not a substitute for sleep, rest, or dealing with the source of the stress.
Why B Vitamins Might Influence Stress
The trials do not prove a mechanism, but the biochemistry offers plausible explanations. Vitamin B6 is a cofactor in making serotonin, dopamine, GABA and noradrenaline. The folate and B12 cycle supplies methyl groups and helps regenerate a cofactor needed to make these monoamine messengers. Pantothenic acid, through coenzyme A, takes part in making neurotransmitters and steroid hormones. If any of these vitamins is in short supply, these pathways may run less efficiently.
That is also why the people who benefit most tend to be those whose status was low to begin with. Young and colleagues concluded that B vitamin supplements may particularly help people who are at risk because of poor nutrient status or poor mood status.
Who Is Most Likely to Benefit
- People with low intake. Diets with few whole grains, legumes, leafy greens or animal foods can fall short on several B vitamins at once.
- Older adults. Conditions that reduce stomach acid, such as atrophic gastritis, become more common with age and lower vitamin B12 absorption from food; low B12 status is common in older people.
- Vegetarians and vegans. Vitamin B12 occurs naturally only in animal foods, so plant-based eaters need fortified foods or a supplement.
- People taking certain medications. Acid-reducing drugs and metformin can lower B12 absorption, and some antiepileptic drugs lower B6 and folate levels.
Food Sources of the Key B Vitamins
| Vitamin | Adult daily need (RDA) | Good food sources |
|---|---|---|
| Vitamin B6 | 1.3 mg (ages 19-50); 1.5-1.7 mg after 50 | Fish, beef liver and other organ meats, potatoes and other starchy vegetables, non-citrus fruit, fortified cereals, poultry |
| Folate (B9) | 400 mcg DFE | Dark green leafy vegetables, beans, peas, nuts, spinach, asparagus, Brussels sprouts, enriched grains |
| Vitamin B12 | 2.4 mcg | Fish, meat, poultry, eggs, dairy, fortified breakfast cereals and nutritional yeast |
| Pantothenic acid (B5) | 5 mg (Adequate Intake) | Beef, chicken, organ meats, whole grains, some vegetables |
| Niacin (B3) | 16 mg NE (men); 14 mg NE (women) | Poultry, beef, fish, nuts, legumes, grains |
A varied diet that includes these foods covers the B vitamin needs of most healthy adults. Magnesium-rich foods are another useful part of a calm-supporting diet; see our article on foods high in magnesium and their calming effects.
B-Complex or Multivitamin?
Most of the trials above used either a B-complex or a multivitamin that included the B group, often at doses well above the RDAs. A B-complex usually supplies larger amounts of each B vitamin; for example, B-complex products commonly contain 50 to 500 mcg of vitamin B12, while multivitamins typically contain 5 to 25 mcg. A multivitamin adds other vitamins and minerals at lower doses.
If you prefer a single daily capsule, OPA's Men's Daily Multivitamin includes a B-vitamin complex with thiamine, riboflavin, niacin, vitamin B6, folate, vitamin B12 and pantothenic acid to support energy metabolism, alongside vitamin C, vitamin E, zinc, magnesium and selenium. The product description does not list the amount of each B vitamin, so check the Supplement Facts label and compare it with the doses used in the studies before expecting similar results. For how much of each B vitamin is enough and where the safety limits sit, see our B-complex dosage and safety limits guide.
Supplements work best as one part of a broader plan. Our overview of nutritional interventions for stress relief covers other nutrients and eating habits that have been studied.
Safety and Interactions
B vitamins from food have not been shown to cause harm, but high-dose supplements can.
- Vitamin B6: the US upper limit for adults is 100 mg a day from all sources. Taking 1 to 6 grams a day for a year or more can cause severe sensory neuropathy, and in 2023 the European Food Safety Authority set a much lower adult limit of 12 mg a day. Add up the B6 in every supplement you take.
- Niacin: the upper limit for supplemental niacin is 35 mg a day. Doses of 30 to 50 mg or more of nicotinic acid commonly cause flushing, and much higher doses can affect the liver.
- Folic acid: the upper limit is 1,000 mcg a day from supplements and fortified foods, partly because large amounts can mask a vitamin B12 deficiency.
- Biotin: high-dose biotin can interfere with some lab tests, including thyroid and heart tests. Tell your clinician if you take it.
Talk to your doctor or pharmacist before taking a B-complex if you take antiepileptic medicines (such as phenytoin, carbamazepine or valproate), methotrexate, sulfasalazine, acid-reducing medicines, metformin, or theophylline. If stress feels constant or is affecting your sleep, work or relationships, speak with a healthcare professional.
Frequently Asked Questions
Can B vitamins really help reduce stress?
Modestly. Meta-analyses of randomized trials found that adults taking B-complex or B-rich multivitamin supplements for at least four weeks reported slightly lower perceived stress than those on placebo. The benefit is small and seems larger in people whose B vitamin intake or status was low.
Which B vitamins matter most for stress?
Vitamin B6, folate, vitamin B12 and pantothenic acid have the clearest roles in making neurotransmitters and hormones, but the B vitamins work as a team. Most positive trials used formulas containing several B vitamins rather than a single one.
How long does it take for B vitamins to affect stress levels?
The trials ran from four weeks to three months. The 2011 work stress trial measured its main results after 12 weeks, so give any change at least a month or two before judging it.
What are the signs of low B vitamin status?
Signs vary by vitamin. Low B12 can cause fatigue and numbness or tingling in the hands and feet, and low B6 can cause cracks at the corners of the mouth, a swollen tongue and confusion. These signs have many other causes, so ask your doctor about a blood test rather than guessing.
Are there side effects of B vitamin supplements?
At normal doses, B vitamins are well tolerated. Problems come from high doses: long-term excess vitamin B6 can damage sensory nerves, niacin can cause flushing, and too much folic acid can hide low B12. Check labels and stay under the upper limits.
Sources
- NIH Office of Dietary Supplements. Vitamin B6: Fact Sheet for Health Professionals.
- NIH Office of Dietary Supplements. Folate: Fact Sheet for Health Professionals.
- NIH Office of Dietary Supplements. Vitamin B12: Fact Sheet for Health Professionals.
- NIH Office of Dietary Supplements. Niacin: Fact Sheet for Health Professionals.
- NIH Office of Dietary Supplements. Pantothenic Acid: Fact Sheet for Health Professionals.
- NIH Office of Dietary Supplements. Biotin: Fact Sheet for Health Professionals.
- Young LM, Pipingas A, White DJ, Gauci S, Scholey A. A Systematic Review and Meta-Analysis of B Vitamin Supplementation on Depressive Symptoms, Anxiety, and Stress: Effects on Healthy and 'At-Risk' Individuals. Nutrients. 2019.
- Long SJ, Benton D. Effects of vitamin and mineral supplementation on stress, mild psychiatric symptoms, and mood in nonclinical samples: a meta-analysis. Psychosom Med. 2013.
- Stough C, Scholey A, Lloyd J, et al. The effect of 90 day administration of a high dose vitamin B-complex on work stress. Hum Psychopharmacol. 2011.
- Kennedy DO. B Vitamins and the Brain: Mechanisms, Dose and Efficacy--A Review. Nutrients. 2016.
Disclosure: OPA Nutrition sells supplements, including products mentioned in this article. This content is for education only and is not medical advice. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your healthcare provider before using any supplement, especially if you take medication or have a medical condition.
Written and reviewed by Michael Gonzales, Founder, OPA Nutrition · Last reviewed: · How OPA researches and writes
