Several supplements have meaningful clinical evidence behind them for reducing anxiety symptoms, with ashwagandha, L-theanine, magnesium, and lavender extract among the most studied. None are a guaranteed fix, and they work best alongside foundational habits like sleep, exercise, and stress management. But if you’re looking for something to take the edge off, here’s what the research actually supports.
Ashwagandha
Ashwagandha is one of the most well-studied supplements for anxiety. An international task force created by the World Federation of Societies of Biological Psychiatry and the Canadian Network for Mood and Anxiety Treatments has provisionally recommended 300 to 600 mg of ashwagandha root extract daily for generalized anxiety disorder. That’s a notable endorsement for a supplement, since most never make it into clinical guidelines at all.
Clinical trials have used doses ranging from 240 to 1,250 mg per day of root extract, typically standardized to contain a specific percentage of withanolides (the active compounds). Most positive results come from extracts standardized to about 2.5% to 5% withanolides, taken for 30 to 90 days. Studies consistently show reductions in cortisol, a key stress hormone, compared to placebo, though the size of that reduction varies between trials.
One thing to be aware of: ashwagandha can influence thyroid function. A trial of 50 people with mildly underactive thyroids found that 300 mg twice daily for eight weeks raised thyroid hormone levels. If you have a thyroid condition or take thyroid medication, this is worth discussing with your doctor before starting.
L-Theanine
L-theanine is an amino acid found naturally in green tea, and it works differently from most calming supplements. Rather than making you drowsy, it promotes a relaxed-but-alert state by boosting alpha brain wave activity, the same pattern your brain produces during calm, focused attention. A clinical trial found that 200 mg of L-theanine significantly increased alpha wave activity and lowered heart rate in people with high anxiety, with effects measurable within 15 to 60 minutes of a single dose.
That fast onset makes L-theanine especially practical. You can take it before a stressful event and feel a difference relatively quickly. The standard dose in research is 200 mg, and it’s one of the supplements least likely to cause side effects or interact with medications. Many people stack it with their morning coffee to smooth out the jittery edge of caffeine.
Magnesium
Magnesium plays a role in over 300 enzyme systems in your body, including the production of serotonin, the neurotransmitter most closely tied to mood regulation. It also influences brain chemistry through pathways involved in depression and anxiety. Despite this strong biological rationale, the evidence in human studies is less definitive than the marketing suggests. Mayo Clinic notes that while magnesium is often promoted for relaxation, sleep, and mood, it hasn’t been conclusively proven in human trials for those purposes.
That said, many people don’t get enough magnesium from food alone, and correcting a deficiency can improve how you feel overall. The recommended daily intake is 310 to 320 mg for adult women and 400 to 420 mg for adult men. Magnesium glycinate is the form most commonly recommended for anxiety because it’s well absorbed and less likely to cause digestive issues than cheaper forms like magnesium oxide. If your diet is low in nuts, seeds, leafy greens, and whole grains, a supplement is reasonable regardless of its direct anxiety effects.
Lavender Oil (Silexan)
Oral lavender oil capsules are one of the more surprising entries on this list. A standardized preparation called Silexan, taken at 80 mg per day, has been tested head-to-head against lorazepam (a benzodiazepine commonly prescribed for anxiety) in a six-week trial involving patients with generalized anxiety disorder. The result: lavender oil and lorazepam produced comparable reductions in anxiety scores, with the difference between them falling within a narrow margin of just a few points.
Across multiple trials involving over 500 participants, Silexan at 80 mg daily was superior to placebo for subthreshold anxiety and comparable to a low-dose benzodiazepine for generalized anxiety disorder. This isn’t the same as putting lavender essential oil in a diffuser. The clinical evidence is specifically for standardized oral capsules, so look for products that contain 80 mg of Silexan or a similar standardized lavender oil extract.
Omega-3 Fatty Acids
Omega-3s, the fats found in fatty fish like salmon and sardines, have a growing body of evidence for mood support. The most effective formulations appear to contain at least 60% EPA relative to DHA, the two main types of omega-3s. Clinical trials typically use 1 to 2 grams per day of combined EPA and DHA, though some have gone as high as 6 to 10 grams.
Most of the omega-3 research focuses on depression rather than anxiety specifically, but since the two conditions frequently overlap and share underlying inflammatory pathways, the benefits often extend to anxious mood as well. When choosing a fish oil supplement, check the label for the EPA and DHA breakdown, not just the total “fish oil” amount. A capsule containing 1,000 mg of fish oil might only deliver 300 mg of actual EPA and DHA. Aim for 1 to 2 grams of combined EPA and DHA daily, with EPA making up the majority.
Vitamin B6
Vitamin B6 serves as a building block for several brain chemicals that regulate anxiety, most importantly GABA. GABA is your brain’s primary “calm down” signal, and dysfunction in the GABA system is one of the core mechanisms behind anxiety disorders. Drugs that enhance GABA activity tend to reduce anxiety, and drugs that block it tend to increase it. B6 acts as a necessary co-enzyme for converting glutamate (an excitatory brain chemical) into GABA.
A study from the University of Reading found that high-dose B6 supplementation reduced self-reported anxiety and increased GABAergic (inhibitory) brain activity. B6 is also involved in producing serotonin, dopamine, and noradrenaline. While most people get adequate B6 from food, those with restricted diets or higher stress loads may benefit from supplementation. B6 is water-soluble, so your body excretes what it doesn’t need, but very high doses taken long-term can cause nerve issues, so staying within a reasonable range matters.
Valerian Root
Valerian root has been used for centuries as a calming herb, and modern research has identified a plausible mechanism: it appears to increase the amount of GABA available in the brain by promoting its release from nerve endings and blocking its reabsorption. One of its active compounds, valerenic acid, also inhibits an enzyme that breaks GABA down, effectively keeping more of this calming neurotransmitter circulating.
Clinical trials have used doses ranging from 400 to 900 mg of aqueous valerian extract, typically taken in the evening. One trial compared 600 mg of standardized valerian extract to 10 mg of oxazepam (a benzodiazepine) over 28 days for insomnia, suggesting researchers consider it a credible enough option to test against prescription medication. Valerian is better studied for sleep than for daytime anxiety, so it’s most useful if your anxiety peaks at night or disrupts your ability to fall asleep.
Supplements to Avoid With Anxiety Medications
If you take an SSRI or SNRI (common prescription antidepressants that also treat anxiety), two supplements pose a serious risk. St. John’s wort and 5-HTP both increase serotonin activity in the brain. Combining either one with an SSRI can push serotonin levels dangerously high, triggering serotonin syndrome. Symptoms include confusion, rapid heartbeat, tremor, muscle twitching, and profuse sweating. In severe cases, it can cause seizures, dangerous fever, or loss of consciousness. Neither St. John’s wort nor 5-HTP should be taken alongside SSRIs under any circumstances.
Kava and valerian carry a milder but still meaningful risk when combined with SSRIs. Both can amplify side effects like drowsiness, dizziness, and impaired coordination. This doesn’t mean they’re off-limits, but you should be cautious about timing and dosing, especially when driving or doing anything that requires sharp focus. Ashwagandha, L-theanine, magnesium, and omega-3s generally have cleaner safety profiles when taken alongside prescription medications, though it’s always worth mentioning any supplement to your prescriber so they can flag anything specific to your situation.