Does Ashwagandha Raise Blood Pressure?

Ashwagandha is one of the most popular herbs sold in the United States, often marketed for stress, sleep, and energy. The short answer to whether it raises blood pressure is: in most people, standard doses do not appear to raise blood pressure, and some research suggests it may modestly lower it. But “most people” and “standard doses” are doing real work in that sentence, and several groups should be cautious.

Ashwagandha (Withania somnifera) is an adaptogenic herb used in Ayurvedic medicine for centuries. Modern interest centers on its potential effects on cortisol, the body’s primary stress hormone. Because chronic stress and elevated cortisol are linked to higher blood pressure, some researchers have asked whether calming that stress response might help blood pressure. The evidence is interesting but not conclusive, and it comes with important caveats about dose, form, and who should avoid it.

What Does the Research Actually Show About Ashwagandha and Blood Pressure?

The most direct human evidence comes from small clinical trials, and the results have generally pointed toward mild reductions rather than increases. A frequently cited randomized controlled trial published in the Indian Journal of Psychological Medicine found that participants taking a standardized ashwagandha root extract for eight weeks had lower cortisol levels and modestly lower blood pressure compared with a placebo group. That study was small, and small trials can overstate effects.

Other trials in stressed adults have reported similar directional findings: slight drops in systolic and diastolic pressure, alongside improvements in self-reported stress and sleep. A meta-analysis pooling several of these studies suggested a small average reduction in blood pressure, but the authors noted significant limitations, including short durations, small sample sizes, and variation in the type of extract used.

What the research does not show is a reliable, large blood pressure-lowering effect. The changes observed are typically small and sometimes not statistically significant. And crucially, none of these studies were designed to test ashwagandha as a blood pressure treatment. They were stress and sleep studies that happened to measure blood pressure as a secondary outcome.

So the honest summary: the weight of current evidence does not support the idea that ashwagandha raises blood pressure in healthy adults at typical doses. It may slightly lower it in some people, but the effect is modest and the studies are limited.

How Could Ashwagandha Affect Blood Pressure at All?

Blood pressure is regulated by a complex mix of factors: the nervous system, hormone signals, blood vessel tone, kidney function, and fluid balance. Ashwagandha’s proposed effects touch several of these pathways, though most of the mechanism research comes from animal and laboratory studies rather than humans.

One leading theory involves the hypothalamic-pituitary-adrenal (HPA) axis, the system that governs the stress response. Chronic stress keeps this axis activated, raising cortisol and adrenaline, which can tighten blood vessels and increase heart rate over time. Some research suggests ashwagandha compounds called withanolides may dampen this stress response, which in theory could relax blood vessel tone.

Other laboratory work points to effects on nitric oxide, a molecule that helps blood vessels widen. If ashwagandha supports nitric oxide signaling, that could lower pressure rather than raise it. These mechanisms are plausible, but biological plausibility is not the same as proven clinical benefit. A pathway making sense in a lab dish does not guarantee a meaningful effect in a living person.

There is also a separate consideration: ashwagandha is sometimes taken for energy and stimulation. If a product is combined with caffeine or other stimulants in an “energy” formula, the stimulant — not the ashwagandha — is the more likely culprit for a blood pressure rise.

Who Should Be Cautious About Ashwagandha and Blood Pressure?

Even if ashwagandha does not raise blood pressure in the average healthy adult, “average” does not describe everyone. Several groups have reason for extra caution, and in some cases the concern is not about blood pressure specifically.

• People taking blood pressure medication. If ashwagandha does lower blood pressure even slightly, combining it with prescription antihypertensives could push pressure too low in some people. This is a reason to talk with a clinician before combining them, not a reason to assume harm.
• People with autoimmune conditions. Ashwagandha may stimulate parts of the immune system. Some clinicians advise caution in autoimmune disease, though human evidence here is limited.
• People with thyroid conditions. Some research suggests ashwagandha may raise thyroid hormone levels. Anyone with hyperthyroidism or on thyroid medication should be careful, since thyroid activity affects heart rate and blood pressure.
• People who are pregnant or breastfeeding. Ashwagandha is generally not recommended during pregnancy. No clinical guidelines establish a safe dose for pregnant or breastfeeding women, so this group should avoid it unless a clinician specifically advises otherwise.
• People scheduled for surgery. Because it may affect the nervous system and blood pressure, some clinicians recommend stopping ashwagandha before surgery. Follow your surgical team’s instructions.

The bigger practical issue may be the product itself. Supplements are not held to the same standards as prescription drugs in the United States. Potency, purity, and even the identity of the plant material can vary between brands and batches. Some ashwagandha products have been found to contain less of the herb than the label claims, or to be contaminated. That variability means two people taking “ashwagandha” may not be taking the same thing at all.

Can Ashwagandha Raise Blood Pressure in Any Situation?

There is no strong evidence that ashwagandha itself raises blood pressure in healthy adults at typical doses. But a few scenarios could plausibly lead to a rise, and they are worth understanding.

First, individual reactions vary. Herbs are not uniform in their effects, and some people may respond differently than the study averages suggest. A person who notices their blood pressure climbing after starting any new supplement should treat that as a signal to stop and check with a clinician.

Second, the dose and form matter. Most trials used standardized root extracts in the range of a few hundred milligrams per day. High-dose or concentrated products may behave differently, and there is little human data on very high doses.

Third, interactions and combinations matter more than the herb alone. Ashwagandha is often sold in blends with other herbs, stimulants, or ingredients that do have cardiovascular effects. If blood pressure rises after starting a blend, the ashwagandha may not be the cause.

Finally, a rise in blood pressure after starting any supplement could simply be coincidental. Blood pressure fluctuates with stress, sleep, caffeine, salt intake, and time of day. Without measuring before and after, it is hard to know what changed what.

Should You Use Ashwagandha for Blood Pressure?

No. Ashwagandha is not a blood pressure treatment, and no major clinical guideline recommends it for that purpose. The trials that showed modest reductions were not designed to establish it as a therapy, and the effect sizes were small.

If you have high blood pressure, the interventions with strong, consistent evidence behind them are well established: reducing sodium intake, eating a pattern rich in fruits, vegetables, and whole grains, getting regular physical activity, limiting alcohol, not smoking, maintaining a healthy weight, and taking prescribed medication as directed. These are backed by decades of research and large trials. Ashwagandha is not in that category.

If you are considering ashwagandha for stress or sleep and you have normal blood pressure, the evidence suggests it is unlikely to raise your pressure at typical doses. But check with a clinician first if you take blood pressure medication, have a thyroid or autoimmune condition, are pregnant or breastfeeding, or are scheduled for surgery. And choose products from manufacturers that test for purity, since the supplement market is uneven.

One non-obvious point: because ashwagandha may slightly lower blood pressure, the more realistic concern for some people is not a rise but a drop — especially if they are already on medication that lowers pressure. Dizziness or lightheadedness after starting it is worth mentioning to a doctor.

What Is the Bottom Line on Ashwagandha and Blood Pressure?

For most healthy adults taking typical doses, ashwagandha does not appear to raise blood pressure, and some research suggests it may lower it slightly. That said, the studies are small and short, the effects are modest, and the herb is not a treatment for high blood pressure.

If your blood pressure is a concern, focus on the strategies with real evidence behind them and talk with a clinician before adding any supplement. If you decide to try ashwagandha, monitor how you feel, watch for dizziness or other changes, and be honest with your doctor about everything you take.