Vitamins for anxiety: what the evidence says, and what’s safe

If you’ve searched for vitamins for anxiety, you’ll have found plenty of confident lists. The truth is more modest: no vitamin or supplement is a proven treatment for anxiety, and some can do real harm if you take too much.

That doesn’t mean nutrition doesn’t matter. Being low in certain vitamins and minerals can leave you tired, foggy and low, which makes anxiety harder to handle. Here’s what the evidence actually shows, supplement by supplement, and how to stay safe.

This post is general information, not medical advice. Please check with a doctor or pharmacist before you start any supplement, especially if you take other medicines, are pregnant or breastfeeding, or have kidney or liver problems.

The evidence at a glance

Supplement	Evidence for anxiety	Key safety notes
Omega-3 (fish oil)	Some: may help, mainly at higher doses in people with a diagnosed condition	Can affect bleeding with blood thinners
Magnesium	Some, but poor quality	Upper limit 350 mg a day from supplements; diarrhoea; clashes with some antibiotics
Vitamin B6	Early: one trial in young adults	Long-term high doses can damage nerves
B-complex	Helps stress, not anxiety, in a review of trials	Check B6 content
Vitamin D	Mixed; helpful if you’re low	Upper limit 4,000 IU a day; too much is harmful
Vitamin C	Very little: small trials only	Large doses can upset your stomach
Vitamins A, E and K	No good evidence for anxiety	Vitamin A harmful in high doses, especially in pregnancy; E and K affect blood thinners

Omega-3

Omega-3 fats are found in oily fish like salmon, sardines and mackerel, and in fish oil supplements.

The evidence: a 2018 review of 19 trials found that omega-3 was linked to a modest drop in anxiety symptoms. The benefit showed up mainly in people with a diagnosed condition, and at higher doses of at least 2,000 mg a day. At lower doses, it didn’t do better than the comparison groups. The authors said more good-quality trials are needed.

Safety: fish oil can cause a fishy aftertaste, heartburn and nausea. At higher doses it may increase bleeding, so talk to a doctor first if you take a blood thinner like warfarin.

Magnesium

Magnesium is in leafy greens, nuts, seeds, beans and whole grains.

The evidence: a 2017 review of 18 studies found that magnesium might help anxiety in people who were already prone to it, such as people with mild anxiety or premenstrual symptoms. But the authors described the quality of the evidence as poor, and it had no effect on anxiety after giving birth.

Safety: for adults, the upper limit from supplements is 350 mg a day. More than that can cause diarrhoea, nausea and cramps. Very high doses can be dangerous, especially if you have kidney disease. Magnesium can stop some antibiotics (tetracyclines and quinolones) and osteoporosis medicines (bisphosphonates) being absorbed properly, so they need to be taken a few hours apart.

B vitamins

B vitamins help your body turn food into energy and help make brain chemicals.

The evidence: a 2019 review of trials of B-complex supplements found they helped with stress, but had no effect on anxiety. A 2022 trial in young adults found that a high dose of vitamin B6 (100 mg a day) for a month reduced self-reported anxiety slightly. It’s an interesting finding, but it’s one study.

Safety: 100 mg a day is the US upper limit for B6. Taking high doses for a long time can damage nerves, causing numbness and pain in your hands and feet. Don’t try high-dose B6 without talking to a doctor.

When to test: low B12 or folate can cause tiredness, pins and needles, memory problems and low mood. You’re more likely to be low if you’re older, vegan, have stomach or bowel conditions, or take metformin or acid-reducing medicines for a long time. A blood test can check.

Vitamin D

Your body makes vitamin D from sunlight. It’s also in oily fish, eggs and fortified foods.

The evidence: people with anxiety and depression are more likely to have low vitamin D, but that doesn’t prove one causes the other. Trials of vitamin D supplements for anxiety have had mixed results. If you’re low, topping up makes sense for your bones and general health anyway.

Safety: most adults need 600 IU (15 micrograms) a day, or 800 IU over 70. The upper limit is 4,000 IU (100 micrograms) a day. Too much over time can raise the calcium in your blood, causing nausea, confusion, kidney problems and heart rhythm problems.

Vitamin C

The evidence: a few small trials have suggested vitamin C might reduce anxiety slightly. They’re too small to be sure.

Safety: large doses can cause diarrhoea and stomach upset, and may increase the risk of kidney stones in some people.

Vitamins A, E and K

There’s no good evidence that these help anxiety, and each needs care:

• Vitamin A: too much can damage your liver and harm an unborn baby. If you’re pregnant or might be, avoid vitamin A supplements and liver products unless your doctor advises them.
• Vitamin E: high doses can increase bleeding, especially if you take blood thinners.
• Vitamin K: it can stop warfarin working properly. If you take warfarin, keep your vitamin K intake steady and talk to your doctor before any supplement.

What about herbal supplements?

“Natural” doesn’t mean safe:

• St John’s wort interacts with many medicines, including antidepressants, birth control pills and blood thinners.
• Kava has been linked to serious liver damage.
• Ashwagandha has been linked to rare cases of liver injury and shouldn’t be taken in pregnancy.

Always tell your doctor and pharmacist about any herbal supplement you take.

Before you buy anything

• Get tested first. If you feel tired, low or foggy, ask a doctor about blood tests for vitamin D, B12, folate and iron. Ask about a thyroid test too: an overactive thyroid can cause anxiety, a racing heart and shaking.
• Food first. A varied diet usually gives you what you need.
• Check for a quality seal. In the US, supplements don’t need FDA approval before they’re sold. Seals like USP Verified or NSF Certified show a product has been tested for what’s on the label.
• Watch for doubling up. Multivitamins, “mood” blends and energy drinks can all contain the same vitamins.
• Check with a pharmacist if you take any prescription medicines.

What has the strongest evidence for anxiety

If you’re looking for something that really helps, these have much stronger evidence than any vitamin:

• Cognitive behavioural therapy (CBT), the most researched talking therapy for anxiety
• Regular physical activity
• Medicines prescribed by a doctor, like SSRIs
• Cutting down on caffeine and alcohol, which can both drive anxiety
• Slow breathing and grounding in the moment

Our post on how to calm anxiety covers what helps right now and over time.

Frequently asked questions

What vitamin helps with anxiety the most?

No vitamin has strong evidence for treating anxiety. Omega-3 and magnesium have the most research, and even that is limited. The most useful step is to check you’re not low in vitamin D, B12, folate or iron, because fixing a deficiency can help you feel better overall.

Can a vitamin deficiency cause anxiety?

Low B12, folate, iron and vitamin D can cause tiredness, low mood, poor concentration and a racing heart, which can feel like anxiety or make it worse. A blood test can check. An overactive thyroid can also cause anxiety symptoms.

Can I take vitamins with my anxiety medicine?

Many are fine, but some aren’t. St John’s wort is the best-known example, because it interacts with antidepressants. Ask your pharmacist to check everything you take together.

How long do supplements take to work?

In the trials, people usually took them for at least a month before any change was measured. If you try one, give it a few weeks, keep track of how you feel and stop if you get side effects.

How Breatheasy can help

Breatheasy helps with the things that have the strongest evidence for calming anxiety. Guided breathing exercises pulse your phone as you breathe in, so you can follow along with your eyes closed. If you’re trying a change, like a new supplement or less caffeine, ten-second check-ins and a journal help you see whether it’s making a difference. Breatheasy is coming soon to iPhone and Android.

Sources

• Association of use of omega-3 fatty acids with changes in severity of anxiety symptoms, Su and others, JAMA Network Open, 2018
• The effects of magnesium supplementation on subjective anxiety and stress, Boyle and others, Nutrients, 2017
• B vitamin supplementation on depressive symptoms, anxiety and stress, Young and others, Nutrients, 2019
• High-dose vitamin B6 supplementation reduces anxiety, Field and others, Human Psychopharmacology, 2022
• Magnesium fact sheet, NIH Office of Dietary Supplements
• Vitamin D fact sheet, NIH Office of Dietary Supplements
• Vitamin B6 fact sheet, NIH Office of Dietary Supplements
• Vitamin A, NHS
• Using dietary supplements wisely, National Center for Complementary and Integrative Health