Can ashwagandha cause heart palpitations? What the research does and doesn't show

No dedicated trial has tested whether ashwagandha causes or relieves heart palpitations. Two separate pieces of research are relevant to the question, though: a 2018 review of case reports lists ashwagandha among a short list of herbs linked to heart-related problems, and a placebo-controlled trial shows ashwagandha extract can measurably raise thyroid hormone levels — a well-known cause of a racing or pounding heartbeat.

What the evidence doesn't support

It doesn't support ashwagandha as a treatment for heart palpitations, an irregular heartbeat, atrial fibrillation, or any other heart condition. It also doesn't support a firm statement that ashwagandha reliably causes palpitations in a general population — no trial has measured that directly. What exists is a case-report signal and a plausible mechanism, not a controlled study of ashwagandha's effect on heart rhythm.

What the trials found

A 2018 research summary compiled published, PubMed-documented case reports (spanning 1966 to 2016) of dietary supplements and herbs linked to heart-related problems, building an online reference table for clinicians. Out of a very large number of herbs and supplements searched, the review identified about seven with documented heart-toxicity case reports — four traditional Chinese medicine herbs, two North American herbs, and one Ayurvedic herb: ashwagandha. The spectrum of heart problems reported across all of these herbs combined included tachycardia, arrhythmia, and other rhythm and blood-pressure effects, but the review's own abstract doesn't break out the specific dose, number of cases, or exact symptom reported for ashwagandha individually — it names ashwagandha as one of the herbs with a documented case, without giving the case's details.

Separately, there's a documented mechanism that connects ashwagandha to a racing heartbeat indirectly: thyroid hormone. A randomized, placebo-controlled trial gave 50 adults with subclinical hypothyroidism either 600 mg/day of ashwagandha root extract or placebo for 8 weeks, and found ashwagandha significantly raised T3 and T4 and lowered TSH compared with placebo. Excess thyroid hormone — whether from a thyroid condition or, in principle, from something that raises it — is a well-established cause of a fast or pounding heartbeat. That trial didn't measure palpitations directly, and it used an extract at a dose different from most root-powder capsules, but it's the clearest mechanistic reason ashwagandha shows up in this conversation at all.

Questions people ask

Can ashwagandha cause palpitations?

There's a documented case-report link and a plausible mechanism (its effect on thyroid hormone), but no controlled trial has measured how often, or at what dose, ashwagandha causes palpitations in a general population. If you notice a new or unusual heartbeat pattern after starting ashwagandha, that's worth mentioning to a doctor rather than waiting it out.

Does ashwagandha affect heart rate?

No trial has measured ashwagandha's direct effect on heart rate. Its documented effect on thyroid hormone (raising T3 and T4) is a plausible indirect route to a faster heart rate, since thyroid hormone strongly influences heart rate and rhythm.

Is ashwagandha safe for the heart?

The evidence isn't extensive enough to say yes or no in general. A case-report review lists ashwagandha among herbs linked to heart-related problems, and there's a documented thyroid-hormone effect that's relevant to anyone with an existing heart or thyroid condition. Anyone with a heart condition, arrhythmia, or thyroid condition should talk to a doctor before taking ashwagandha.

When to talk to a doctor

Ashwagandha is not a treatment for heart palpitations, an irregular heartbeat, or any other heart condition. New or persistent palpitations — especially alongside dizziness, chest pain, shortness of breath, or fainting — are reasons to see a doctor promptly rather than self-treat. If you have a heart condition, an arrhythmia, or a thyroid condition, or take medication for any of these, talk to a doctor before starting ashwagandha.

Related reading: ashwagandha and thyroid: what the research does and doesn't show, who should not take ashwagandha, and ashwagandha and medications: what to check.