Ashwagandha is widely used to reduce anxiety, but in certain circumstances it can actually trigger or worsen it. This isn’t the typical experience for most people, but it happens often enough that the question deserves a serious answer. The most common routes to ashwagandha-related anxiety involve thyroid stimulation, withdrawal after stopping, drug interactions, and contaminated products.
How Ashwagandha Normally Affects Anxiety
Ashwagandha’s calming effects come from two main pathways. First, it lowers cortisol, your body’s primary stress hormone, by acting on the communication loop between your brain and adrenal glands. Second, it appears to enhance the activity of GABA, a brain chemical that quiets nerve signaling, similar in broad strokes to how alcohol or sedative medications work. Most clinical studies using doses of 250 to 600 mg per day show reductions in self-reported stress and anxiety scores compared to placebo.
So for the majority of users, ashwagandha does the opposite of making you anxious. But those same mechanisms, particularly the GABA pathway and thyroid stimulation, are exactly what can backfire in specific situations.
Thyroid Stimulation and Anxiety
This is probably the most well-documented way ashwagandha can cause anxiety. Ashwagandha stimulates the thyroid gland to produce and release more thyroid hormones. In animal studies, it increased circulating levels of the main thyroid hormone (T4) by roughly 111% over 20 days. That’s a dramatic shift, and in humans it can push thyroid function into overdrive.
When your thyroid produces too much hormone, the resulting condition, thyrotoxicosis, comes with a recognizable set of symptoms: palpitations, tremor, racing heart, irritability, loose stools, hair thinning, and notably, anxiety. A case published in the journal Cureus documented a woman who developed convincing clinical thyrotoxicosis, including tachycardia, tremor, dizziness, and irritability, traced back to her ashwagandha use.
If you already have hyperthyroidism or borderline-high thyroid levels, ashwagandha is particularly risky. It can worsen the very symptoms it’s supposed to help: restlessness, agitation, hand tremors, and anxiety. People with healthy thyroid function are less likely to experience this, but it’s not impossible, especially at higher doses or with prolonged use.
Withdrawal After Stopping
Because ashwagandha enhances GABA activity in the brain, stopping it abruptly after regular use can produce a rebound effect. Your nervous system adapts to that extra calming input, and when it’s suddenly removed, excitatory signals can temporarily dominate. This is the same basic mechanism behind alcohol and benzodiazepine withdrawal, though typically far milder with ashwagandha.
A case report described a 20-year-old man who developed tachycardia, insomnia, and anxiety symptoms after abruptly stopping 600 mg per day of ashwagandha extract. His symptoms mirrored withdrawal patterns seen with other substances that affect GABA pathways. The authors noted that while it’s possible his underlying anxiety simply returned, the timing and severity pointed toward a genuine withdrawal effect.
This area is still poorly documented. Formal withdrawal syndromes from ashwagandha haven’t been widely studied, and no clinical guidelines exist for tapering off. But if you’ve been taking it daily for weeks or months, stopping gradually rather than all at once is a reasonable precaution.
Drug Interactions That Increase Anxiety
Ashwagandha can interact with several categories of medication in ways that may amplify anxiety-like symptoms. The National Center for Complementary and Integrative Health flags interactions with thyroid medications, sedatives, anti-seizure drugs, immunosuppressants, and medications for diabetes and high blood pressure.
The thyroid medication interaction is especially relevant here. If you’re taking thyroid hormone replacement and add ashwagandha, the combined effect could push your thyroid levels too high, producing the anxiety, palpitations, and restlessness described above. Combining ashwagandha with the antidepressant escitalopram has been linked to symptoms including restless legs syndrome, nausea, and muscle pain. Any of these uncomfortable physical effects can feed into or mimic anxiety.
Contaminated or Low-Quality Products
Because supplements aren’t regulated the same way as prescription drugs, product quality varies widely. The FDA has specifically warned that ayurvedic products, the tradition ashwagandha comes from, sometimes contain undisclosed heavy metals like lead, mercury, and arsenic. Chronic exposure to these metals causes nervous system symptoms including agitation, dizziness, confusion, and tingling in the extremities. These symptoms overlap significantly with anxiety and can be misattributed to stress or the supplement’s active ingredients rather than contamination.
Choosing products that carry third-party testing certifications (such as NSF International or USP verification) reduces this risk considerably. Standardized extracts like KSM-66 or Shenandoah tend to have more consistent quality control than generic formulations.
What Anxiety From Ashwagandha Feels Like
If ashwagandha is causing your anxiety rather than helping it, the symptoms typically cluster into a few recognizable patterns. Thyroid-driven anxiety tends to come with physical symptoms: a noticeably faster heart rate, feeling overheated, trembling hands, and sometimes digestive changes like loose stools. It usually develops gradually over days to weeks of use.
Withdrawal-related anxiety tends to appear within days of stopping and feels more like a general nervous agitation, with difficulty sleeping, a racing heart, and heightened alertness. It often resolves on its own within a week or two.
If you started ashwagandha expecting it to calm you down and instead feel more on edge, the simplest first step is to stop taking it and see if the symptoms resolve. If they do, that’s a strong signal the supplement was the issue. If you’ve been on it for a while, consider reducing your dose over a week or two rather than quitting cold.
Who Should Be Cautious
Certain groups face a higher risk of anxiety-related side effects from ashwagandha:
- People with hyperthyroidism or borderline-high thyroid function. Ashwagandha can push already-elevated thyroid hormones higher, directly worsening anxiety, restlessness, and agitation.
- People on thyroid medication. The interaction can create unpredictable hormone levels.
- Long-term daily users considering stopping. The GABA-related rebound effect is most likely after consistent use at moderate to high doses.
- People taking SSRIs or other psychiatric medications. Interactions can produce uncomfortable physical symptoms that mimic or trigger anxiety.
For most healthy adults at standard doses (250 to 600 mg per day), ashwagandha is more likely to reduce anxiety than cause it. But “generally safe” and “safe for everyone” are different statements, and the mechanisms that make ashwagandha effective are the same ones that occasionally make it counterproductive.