Best Supplements for Stress and Anxiety: Evidence-Based Options

If you've searched for the best supplements for stress and anxiety, you'll have found no shortage of opinions. What's harder to find is a straight answer about which ingredients actually have evidence behind them, and which are simply well marketed. This guide looks at the nutrients and botanicals most commonly recommended for stress and what the research says about each.

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• What are the best supplements for stress and anxiety?
• Magnesium for stress
• B vitamins and the nervous system
• Ashwagandha: what the evidence says
• Sleep, stress and where Deep Sleep Complex fits
• Choosing and combining supplements safely
• Frequently asked questions

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What are the best supplements for stress and anxiety?

Stress is the body's response to feeling under pressure, and it's something almost everyone experiences from time to time. Common signs include tiredness, difficulty concentrating, irritability, disrupted sleep and a general feeling of being overwhelmed.¹ Occasional stress is normal and often passes once the pressure eases. Persistent stress or anxiety that's affecting daily life is different, and it's worth speaking to a GP rather than relying on supplements alone.

With that said, several nutrients play a well-established role in normal nervous system and psychological function, and a deficiency in any of them can make you feel more run-down and less able to cope with pressure than you otherwise would. That's the starting point for this guide - supplements can help fill a nutritional gap, but they are not a treatment for stress or anxiety as a condition, and no supplement is authorised to make that claim in the UK.

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Magnesium for stress

Magnesium is involved in hundreds of enzymatic reactions in the body, including those that regulate the nervous system's response to stress.² Research has described a "vicious circle" between magnesium and stress - prolonged stress increases how much magnesium the body loses, and low magnesium status in turn appears to make the nervous system more reactive to stress, which can worsen the very symptoms (fatigue, irritability, poor sleep) that stress already causes.²

Magnesium contributes to normal psychological function, contributes to the reduction of tiredness and fatigue, and contributes to normal muscle function.³ These are modest, deficiency-focused claims rather than promises of stress relief, but they reflect a genuine and well-evidenced role for magnesium in how the nervous system copes with everyday pressure.

Dietary sources include leafy green vegetables, nuts, seeds and wholegrains, but modern diets and processed foods often fall short of recommended intakes. If your diet is inconsistent, or you notice symptoms that overlap with both stress and magnesium deficiency (fatigue, muscle tension, poor sleep), a daily supplement such as OneVit Magnesium is a straightforward way to help close that gap.

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B vitamins and the nervous system

The B vitamins (particularly B1, B2, B6, B12 and folate) are essential cofactors for energy metabolism and neurotransmitter production, and several of them are responsible for normal psychological function and normal function of the nervous system, alongside the reduction of tiredness and fatigue.⁴

The research on B vitamin supplementation specifically for stress is encouraging. A randomised, double-blind, placebo-controlled trial of vitamin B1 and B2 found a significant reduction in Perceived Stress Scale scores after four weeks, compared with placebo.⁵ A separate systematic review and meta-analysis of 16 randomised controlled trials (over 2,000 participants) found that B vitamin supplementation produced a small but statistically significant benefit specifically for the "stress" facet of mood, alongside broader improvements in overall mood in some at-risk groups.⁶

This makes B vitamins one of the better-evidenced categories of vitamins for tiredness and stress, particularly for people whose diet may not consistently meet requirements - including those who drink alcohol regularly, follow a restrictive diet, or are under sustained pressure at work, since stress itself is thought to increase the body's use of several B vitamins. OneVit B Complex provides the full spectrum of B vitamins in one daily dose.

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Ashwagandha: what the evidence says

Ashwagandha (Withania somnifera) is a botanical extract, most often standardised as KSM-66, that has become one of the most widely researched supplements for stress in recent years. A number of randomised, double-blind, placebo-controlled trials have investigated its effects in adults reporting chronic stress. One 60-day trial found that participants taking a standardised ashwagandha extract showed significantly greater reductions in self-reported stress and anxiety scores, and in morning cortisol levels, compared with placebo.⁷ A separate 60-day trial using 300 mg of KSM-66 daily reported similar reductions in stress and anxiety measures using validated psychological scales.⁸

It's important to be clear about what this does and doesn't mean. While this is a genuine and growing body of clinical research, there currently isn't enough evidence or data to cliam, without reasonable doubt, that ashwagandha reduces stress. That doesn't mean it's not effective - ashwaghanda has had traditional use in Ayurvedic practice for centries and there are several human clinical trials looking at self-reported stress levels with promising results.

Ashwagandha is generally well tolerated in trials, though it isn't suitable for everyone. It should be avoided in pregnancy, and people with thyroid conditions, autoimmune disease, or who take sedative or thyroid medication should speak to a GP or pharmacist before starting it, since it may interact with these.⁷ OneVit Ashwagandha KSM-66 uses the same standardised extract studied in the trials referenced above.

If cortisol and stress physiology is something you want to read more about, our separate guide on supplements to reduce cortisol goes into this in more depth.

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Sleep, stress and where Deep Sleep Complex fits

Stress and sleep feed into each other in both directions. Stress makes it harder to fall and stay asleep, and poor sleep leaves the nervous system less able to cope with the next day's pressure - a cycle that you can quickly fall into, but is much harder to break.

Magnesium's role in normal psychological function is relevant here too, since it's one of the more consistently studied nutrients in the context of sleep quality and nervous system regulation.² OneVit Deep Sleep Complex combines magnesium with other ingredients traditionally used to support rest and relaxation. It's worth being clear that, as with any supplement in this category, it's best thought of as one part of a wider approach to winding down rather than a solution on its own, alongside the basics of a consistent bedtime, reduced screen time before bed, and cutting back on caffeine later in the day.

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Choosing and combining supplements safely

A few practical points if you're building a stress-support routine:

• Start with diet and sleep first. Supplements work best alongside, not instead of, the basics - regular meals, consistent sleep, physical activity and cutting back on excess caffeine and alcohol, all of which affect how the body handles stress.
• You generally don't need everything at once. Magnesium and B vitamins are reasonable, low-risk starting points for most adults. Ashwagandha is worth considering if you want to explore the research further, but check the precautions above first.
• Check for interactions. If you take prescribed medication, particularly for thyroid conditions, blood pressure, or mental health, speak to a pharmacist or GP before adding a new supplement, especially ashwagandha.
• Give it time. Nutrient-based approaches tend to work gradually. Most of the trials referenced in this article ran for four to eight weeks before showing a measurable difference.
• Know when to seek more support. Supplements are not an alternative to professional help. If stress or anxiety is persistent, severe, or affecting your ability to function day to day, speak to a GP. NHS Every Mind Matters also has free, practical tools for managing stress.¹

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Frequently asked questions

What is the best supplement for stress and anxiety? There isn't a single "best" supplement, since it depends on what might be lacking in your diet. Magnesium and B vitamins have the most consistent evidence and the clearest claims for normal psychological function. Ashwagandha has promising clinical trial data but it's benefits haven't been fully established yet.

Can vitamins cure anxiety? No. Vitamins and supplements cannot cure, treat or prevent anxiety as a condition. They may help support normal nervous system and psychological function, particularly if you have a nutritional shortfall, but persistent or severe anxiety should be discussed with a GP.

How long does magnesium take to work for stress? Most research looking at magnesium and stress-related outcomes has assessed effects over several weeks rather than days, so it's reasonable to allow at least four weeks of consistent use before judging whether it's making a difference.

Is ashwagandha safe to take every day? In the clinical trials referenced in this article, daily ashwagandha (commonly 300 to 600 mg of standardised extract) was well tolerated over 60 days. It isn't suitable during pregnancy, and people with thyroid conditions, autoimmune disease, or on sedative or thyroid medication should check with a GP or pharmacist first.

Can you take magnesium and B vitamins together? Yes, magnesium and B vitamins are commonly taken together and don't have known interactions with each other. Many people take them as part of a broader daily routine alongside a balanced diet.

What vitamin deficiency causes tiredness and stress-like symptoms? Low magnesium, low B12, and low folate are among the most common deficiencies linked to tiredness, low mood and reduced resilience to stress. A GP can arrange a blood test if you suspect a genuine deficiency rather than a general dietary gap.

When should I see a GP about stress or anxiety? If stress or anxiety is persistent, severe, affecting your sleep, work or relationships, or accompanied by low mood that doesn't lift, it's worth speaking to a GP. Supplements are not a substitute for professional support.

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References

1. NHS. Every Mind Matters: Stress. www.nhs.uk/every-mind-matters/mental-health-issues/stress/
2. Pickering G, Mazur A, Trousselard M, et al. Magnesium Status and Stress: The Vicious Circle Concept Revisited. Nutrients. 2020;12(12):3672. https://pmc.ncbi.nlm.nih.gov/articles/PMC7761127/
3. GOV.UK. Great Britain Nutrition and Health Claims (NHC) Register. https://www.gov.uk/guidance/great-britain-nutrition-and-health-claims-nhc-register
4. EFSA. Scientific Opinion on health claims related to vitamin B12, vitamin B6 and riboflavin and contribution to normal psychological and neurological function. https://efsa.europa.eu/en/efsajournal/pub/1756
5. Tao Y, Wu M, Su B, et al. Impact of Vitamin B1 and Vitamin B2 Supplementation on Anxiety, Stress, and Sleep Quality: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients. 2025;17(11):1821. https://pmc.ncbi.nlm.nih.gov/articles/PMC12157762/
6. Young LM, Pipingas A, White DJ, et al. A Systematic Review and Meta-Analysis of B Vitamin Supplementation on Depressive Symptoms, Anxiety, and Stress. Nutrients. 2019;11(9):2232. https://pmc.ncbi.nlm.nih.gov/articles/PMC6770181/
7. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomised, double-blind, placebo-controlled study. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6750292/
8. KSM-66 Brand Ashwagandha Reduces Stress, Study Confirms. Nutritional Outlook, reporting on a 60-day randomised, double-blind, placebo-controlled trial published in the Indian Journal of Psychological Medicine. https://www.nutritionaloutlook.com/view/ksm-66-brand-ashwagandha-reduces-stress-study-confirms

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This article is for informational purposes only and does not constitute medical advice. If you are concerned about stress or anxiety, consult a GP or qualified healthcare professional.