Ashwagandha is generally not considered dangerous for people with high blood pressure, but there’s an important caveat: it may lower blood pressure on its own, which can cause problems if you’re already taking blood pressure medication. The National Institutes of Health flags a potential interaction between ashwagandha and antihypertensive drugs, and the concern is that combining them could push your blood pressure too low.
What Ashwagandha Actually Does to Blood Pressure
Ashwagandha’s reputation as a blood pressure aid comes mostly from its stress-reducing effects. It works on the body’s stress response system by dialing down cortisol, the hormone your adrenal glands release when you’re under pressure. Chronically elevated cortisol contributes to higher blood pressure, so the logic is straightforward: less stress hormone, less pressure on your cardiovascular system. One of ashwagandha’s active compounds also acts on GABA receptors in the brain, the same targets that anti-anxiety medications like diazepam use, producing a calming effect that can further ease stress-related blood pressure spikes.
The actual clinical evidence for blood pressure reduction, however, is modest. In a 12-week randomized, double-blind trial of 120 stressed, overweight adults taking 400 mg daily of ashwagandha root extract, participants reported feeling less stressed, but their blood pressure readings did not change significantly compared to placebo. This suggests that while ashwagandha reliably lowers perceived stress and cortisol levels, those changes don’t automatically translate into measurable drops in blood pressure for most people.
The Real Risk: Combining It With BP Medication
If you’re not on any blood pressure medication, ashwagandha is unlikely to cause a dangerous drop. The concern grows when you’re already taking drugs designed to lower your numbers. WebMD and the NIH’s National Center for Complementary and Integrative Health both note that ashwagandha might have an additive effect with antihypertensive medications, potentially pushing blood pressure lower than intended. Symptoms of blood pressure dropping too low include dizziness, lightheadedness, blurred vision, and fainting.
This interaction isn’t limited to one class of medication. Whether you take ACE inhibitors, beta-blockers, calcium channel blockers, or diuretics, the same general caution applies. If you do decide to take ashwagandha alongside any of these, monitoring your blood pressure at home more frequently is a practical first step so you can catch any unusual dips early.
Doses Used in Research
Clinical studies have tested a wide range of doses. The 12-week blood pressure trial used 200 mg of root extract (standardized to 1.5% withanolides) taken twice daily, totaling 400 mg per day. Cognitive and stress studies have used as little as 225 mg per day of a liposomal formulation, which was enough to reduce stress markers and improve mental clarity over 30 days. Most supplements on the market fall in the 300 to 600 mg per day range.
Higher doses are more likely to amplify any blood-pressure-lowering effect, so starting at the low end makes sense if you have hypertension. The type of extract matters too. Products standardized to a specific percentage of withanolides (the main active compounds) are more predictable in their effects than unstandardized root powder, which can vary widely between brands.
Other Cardiovascular Effects Worth Knowing
Beyond blood pressure, ashwagandha appears to nudge a few other cardiovascular markers. In one study using 225 mg per day, participants saw a significant increase in HDL cholesterol (the protective kind) along with an improved ratio of HDL to total cholesterol. These are small, early findings, but they suggest ashwagandha’s cardiovascular effects extend beyond blood pressure alone. It also has documented anti-inflammatory properties, which matter because chronic inflammation plays a role in arterial stiffness and long-term heart disease risk.
Who Should Avoid It Entirely
The NIH recommends against ashwagandha for people about to undergo surgery. The blood-pressure-lowering potential, combined with anesthesia (which also drops blood pressure), creates a risk of dangerous hypotension on the operating table. Most practitioners advise stopping herbal supplements at least two weeks before a scheduled procedure, though specific guidance varies.
People with autoimmune conditions or thyroid disorders are also advised to skip ashwagandha. It can stimulate immune activity, which is the opposite of what you want when your immune system is already overactive. And it has been shown to increase thyroid hormone levels, a problem for anyone with hyperthyroidism or anyone carefully managing hypothyroidism with medication. If you take sedatives, anti-seizure drugs, diabetes medications, or immunosuppressants, the NIH also flags potential interactions with each of these categories.
Practical Takeaways for People With High Blood Pressure
Ashwagandha is not inherently off-limits if you have high blood pressure. For people managing hypertension through lifestyle changes alone (diet, exercise, stress reduction), it may even complement those efforts modestly, though the clinical evidence for direct blood pressure reduction remains thin. The real caution is for people already on antihypertensive medication, where the combination could cause blood pressure to dip unpredictably.
If you’re considering it, a home blood pressure monitor becomes your best tool. Take readings at consistent times for a week before starting ashwagandha to establish your baseline, then continue monitoring after you begin. Any sustained drop of more than 10 points in your systolic reading, or symptoms like persistent dizziness, would be worth flagging to whoever manages your blood pressure care.