Ashwagandha (Withania somnifera) is an adaptogenic herb widely regarded in Ayurvedic medicine for its ability to help the body manage stress. This shrub, sometimes called Indian ginseng, has been used for thousands of years to promote energy, enhance focus, and support overall well-being. The plant contains a group of compounds known as withanolides, which are believed to be responsible for many of its beneficial effects. This article examines the current scientific evidence regarding Ashwagandha’s specific influence on blood pressure regulation.
Scientific Findings on Blood Pressure Regulation
Clinical research suggests Ashwagandha may have a modest effect on lowering blood pressure, particularly in individuals with stress-related or mild hypertension. Studies involving stress-oriented subjects have reported a significant reduction in diastolic blood pressure (DBP) after supplementation. This suggests the herb primarily addresses the lower number of a blood pressure reading, which reflects the pressure in the arteries when the heart is resting between beats.
The effect on systolic blood pressure (SBP), the upper number measuring pressure during a heartbeat, appears less consistent across trials. While some studies noted an average reduction of approximately 5 mmHg in SBP, other controlled trials found the decrease to be non-significant. Ashwagandha generally does not cause significant changes in blood pressure in healthy individuals. Therefore, it is not currently recommended as a first-line treatment for established hypertension.
The most promising evidence comes from studies focused on stress-induced cardiovascular changes. When healthy young males were subjected to mental stress, those who had taken Ashwagandha showed lower radial and aortic blood pressure measurements compared to the placebo group. This finding suggests the herb’s positive influence on blood pressure is most notable when the body is reacting to psychological stress.
Mechanisms of Action Relevant to Cardiovascular Health
The primary way Ashwagandha influences blood pressure is through its adaptogenic properties. The herb helps modulate the hypothalamic-pituitary-adrenal (HPA) axis, the body’s central stress response system. By regulating this axis, Ashwagandha helps to lower elevated levels of the stress hormone cortisol.
Chronic high cortisol levels contribute to elevated blood pressure by increasing heart rate and constricting blood vessels. The reduction in circulating cortisol achieved by Ashwagandha can lead to a slight relaxation of blood vessels and a decrease in systemic pressure. This indirect mechanism explains why the hypotensive effect is often observed in individuals whose high blood pressure is linked to chronic stress.
Ashwagandha also contains withanolides that exhibit potent antioxidant activities, offering a secondary protective mechanism. Oxidative stress can damage the lining of blood vessels, leading to stiffness and increased blood pressure. By reducing markers of oxidative stress, such as malondialdehyde (MDA), the herb may help preserve the flexibility and function of the arteries.
Safety Profile and Critical Drug Interactions
Ashwagandha is generally considered safe for short-term use, typically up to three months. However, individuals who are pregnant or breastfeeding should avoid it due to potential risks. The herb should also be avoided by people with autoimmune disorders, such as rheumatoid arthritis, lupus, or Hashimoto’s thyroiditis, because it may increase immune system activity.
A major consideration involves its interaction with prescription medications, particularly those used to manage blood pressure. Combining Ashwagandha with antihypertensive drugs—such as ACE inhibitors or beta-blockers—could cause blood pressure to drop too low, leading to hypotension, dizziness, or fainting. Individuals taking any medication for hypertension must consult their physician before starting supplementation.
The herb also interacts with other classes of drugs. Due to its mild calming effect, combining it with sedatives or central nervous system depressants can lead to excessive drowsiness. Ashwagandha may increase thyroid hormone levels, posing a risk of hyperthyroidism when taken with replacement medications like levothyroxine. Discontinue use at least two weeks before any scheduled surgery due to its potential to interfere with anesthesia.
Practical Dosage and Quality Considerations
For general stress reduction, the standard effective dosage of Ashwagandha root extract typically ranges from 300 to 600 milligrams per day. This daily dose is often split into two equal servings and should be taken consistently to maintain stable levels of active compounds. Effectiveness relies heavily on the concentration of withanolides, so consumers should look for extracts standardized to a specific percentage, such as 2.5%.
Ashwagandha is available in various forms, including capsules, powders, and liquid tinctures, with capsules being the most common form used in clinical studies. Quality sourcing is paramount when selecting a product. High-quality supplements should explicitly state that they undergo third-party testing to ensure purity and confirm the absence of heavy metals, pesticides, and other contaminants. Starting with a lower dose and gradually increasing it while monitoring the body’s response is a sensible approach.