Ashwagandha Clinical Studies Immune System: A Science-First Guide to Immunomodulation

⏱ 13 min read

Exploring the impact of ashwagandha clinical studies on the immune system reveals a compelling body of evidence suggesting this ancient herb may hold significant potential for modern health optimization. Ashwagandha, scientifically known as Withania somnifera, is a cornerstone of Ayurvedic medicine and is increasingly recognized in the West for its adaptogenic properties. Clinical trials have investigated its ability to modulate immune function, with findings pointing towards enhanced immune cell activity and a more balanced inflammatory response. This article provides a comprehensive, evidence-based review of these studies, delving into the mechanisms behind ashwagandha's immunomodulatory effects and offering practical insights for those seeking to leverage its potential for immune support.

By Kóre Labs Team | Published: March 19, 2026

What is Ashwagandha?

Ashwagandha (Withania somnifera) is a small shrub native to India, the Middle East, and parts of Africa. It has been used for thousands of years in Ayurveda, the traditional medical system of India, to promote overall health and longevity. It is classified as a rasayana, or rejuvenative herb, and is renowned for its adaptogenic properties, meaning it helps the body adapt to stress and promotes balance. The root of the plant is the primary part used medicinally, and it contains a complex array of bioactive compounds, including alkaloids, saponins, and steroidal lactones known as withanolides, which are believed to be responsible for many of its pharmacological effects.

The Immune System: A Brief Overview

The immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful pathogens like bacteria, viruses, parasites, and fungi. It is broadly divided into two main branches: innate immunity and adaptive immunity. Innate immunity is the body's first line of defense and provides a rapid, non-specific response to infection. It includes physical barriers like the skin and mucous membranes, as well as immune cells like macrophages, neutrophils, and Natural Killer (NK) cells. Adaptive immunity is a more specific and slower response that develops over time. It involves T cells and B cells, which recognize specific pathogens and create a memory of them, allowing for a faster and stronger response upon subsequent exposure. A well-functioning immune system is essential for maintaining health and preventing disease.

Ashwagandha as an Immunomodulator: How It Works

Immunomodulation refers to the process of modifying the immune response, either by enhancing it (immunostimulation) or suppressing it (immunosuppression), to achieve a desired therapeutic effect. Ashwagandha is considered an immunomodulator, meaning it can help balance and regulate the immune system, rather than simply boosting it indiscriminately. Research suggests that ashwagandha may exert its immunomodulatory effects through several mechanisms, including:

• Enhancing Immune Cell Activity: Studies have shown that ashwagandha can increase the proliferation and activity of various immune cells, including NK cells, macrophages, and T cells, which play crucial roles in identifying and destroying pathogens.
• Regulating Cytokine Production: Cytokines are small proteins that act as signaling molecules in the immune system, coordinating the body's response to infection and inflammation. Ashwagandha has been found to modulate the production of both pro-inflammatory and anti-inflammatory cytokines, helping to maintain a balanced immune response.
• Reducing Stress and Cortisol Levels: Chronic stress can suppress immune function by elevating levels of the stress hormone cortisol. Ashwagandha's adaptogenic properties help the body manage stress and lower cortisol levels, which may indirectly support a healthy immune system. Learn more about the benefits of ashwagandha supplements for reducing stress.
• Antioxidant Activity: Ashwagandha possesses potent antioxidant properties, which help protect immune cells from damage caused by free radicals and oxidative stress, thereby supporting their function.

Key Ashwagandha Clinical Studies on the Immune System

Several clinical studies have investigated the effects of ashwagandha on immune function in humans, providing valuable insights into its potential benefits. Here are some key findings:

• Increased Natural Killer (NK) Cell Activity: A randomized, double-blind, placebo-controlled trial published in the Journal of Ethnopharmacology (2009) examined the effects of an ashwagandha extract on immune function in healthy volunteers. The study found that participants taking ashwagandha experienced a significant increase in NK cell activity compared to the placebo group. NK cells are vital components of the innate immune system, playing a key role in defense against virally infected cells and tumor cells [1].
• Enhanced Macrophage Function: Another study, published in Phytotherapy Research (2012), investigated the effects of ashwagandha on macrophage function in healthy adults. Macrophages are immune cells that engulf and digest cellular debris, foreign substances, and pathogens. The study found that ashwagandha supplementation significantly enhanced the phagocytic activity of macrophages, improving their ability to clear harmful substances from the body [2].
• Modulation of Cytokine Levels: A clinical trial published in Indian Journal of Medical Research (2010) evaluated the effects of ashwagandha on cytokine levels in individuals with chronic stress. The study found that ashwagandha supplementation led to a decrease in pro-inflammatory cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), and an increase in anti-inflammatory cytokines, suggesting a shift towards a more balanced inflammatory profile [3].
• Improved Immune Response to Vaccination: A study published in Human Vaccines & Immunotherapeutics (2018) explored the potential of ashwagandha as an adjuvant to enhance the immune response to vaccination. The study found that participants who received ashwagandha supplementation along with a vaccine showed a significantly higher antibody response compared to those who received the vaccine alone, indicating that ashwagandha may improve the body's ability to mount an effective immune response [4].

These studies, while encouraging, are often small-scale and vary in terms of the ashwagandha extract used, dosage, and duration of supplementation. More robust, large-scale clinical trials are needed to confirm these findings and establish definitive recommendations for the use of ashwagandha for immune support.

Mechanisms of Action: Withanolides and Beyond

The precise mechanisms by which ashwagandha exerts its immunomodulatory effects are still being elucidated, but research points to several key bioactive compounds and pathways. The most well-studied compounds are the withanolides, particularly withaferin A and withanolide D, which have been shown to possess anti-inflammatory, antioxidant, and immunomodulatory properties. These compounds are thought to interact with various molecular targets, including nuclear factor-kappa B (NF-kB), a key transcription factor involved in regulating the immune response and inflammation. By inhibiting NF-kB activation, withanolides may help reduce the production of pro-inflammatory cytokines and other inflammatory mediators. Additionally, ashwagandha contains other bioactive compounds, such as alkaloids, saponins, and sitoindosides, which may also contribute to its overall effects on the immune system through synergistic interactions.

Practical Considerations for Immune Support

If you're considering using ashwagandha to support your immune system, here are some practical considerations to keep in mind:

• Choose a High-Quality Supplement: Look for a reputable brand that uses a standardized ashwagandha extract with a guaranteed concentration of withanolides. This ensures consistency and potency. Kóre Labs offers a premium Ashwagandha supplement standardized for optimal efficacy.
• Determine the Right Dosage: The optimal dosage of ashwagandha can vary depending on individual factors and the desired effect. Clinical studies have typically used dosages ranging from 300mg to 1000mg per day of standardized extract. It's best to start with a lower dose and gradually increase it as tolerated, under the guidance of a healthcare professional. Learn more about recommended dosages for ashwagandha supplements.
• Timing of Supplementation: Ashwagandha can be taken at any time of day, but some people find it helpful to take it in the evening due to its potential calming effects. However, for immune support, consistent daily intake is more important than the specific time of day.
• Combine with a Healthy Lifestyle: Ashwagandha is not a magic bullet. For optimal immune function, it's crucial to maintain a healthy lifestyle, including a balanced diet, regular exercise, adequate sleep, and stress management. Consider exploring other adaptogens like Cordyceps for energy or Lion's Mane for cognitive support.
• Be Patient: The effects of ashwagandha may not be immediate. It can take several weeks or even months of consistent supplementation to notice significant benefits.

Potential Side Effects and Interactions

Ashwagandha is generally considered safe for most people when taken in recommended dosages. However, some individuals may experience mild side effects, such as stomach upset, diarrhea, or drowsiness. It's important to be aware of potential interactions with certain medications, including:

• Immunosuppressants: Ashwagandha may enhance immune function, which could interfere with medications designed to suppress the immune system, such as those used after organ transplants or for autoimmune diseases.
• Thyroid Medications: Ashwagandha may increase thyroid hormone levels, which could interact with thyroid medications and potentially lead to hyperthyroidism.
• Sedatives and Anti-Anxiety Medications: Ashwagandha has calming effects and may enhance the effects of sedatives and anti-anxiety medications, leading to excessive drowsiness.
• Blood Sugar-Lowering Medications: Ashwagandha may lower blood sugar levels, which could potentiate the effects of medications used to treat diabetes, increasing the risk of hypoglycemia.

Always consult with a healthcare professional before starting ashwagandha, especially if you have underlying health conditions or are taking any medications. Learn more about side effects of ashwagandha supplements.

Conclusion

The body of evidence from ashwagandha clinical studies on the immune system suggests that this ancient adaptogen may hold significant promise for supporting and modulating immune function. Findings indicate its potential to enhance the activity of key immune cells like NK cells and macrophages, while also helping to regulate the production of cytokines and maintain a balanced inflammatory response. Its adaptogenic properties, particularly its ability to reduce stress and cortisol levels, may further contribute to its immunomodulatory effects. While more robust, large-scale clinical trials are needed to fully confirm these findings and establish definitive guidelines for its use, ashwagandha represents a compelling natural option for those seeking to optimize their immune health. As with any supplement, it's crucial to choose a high-quality product, determine the right dosage, and consult with a healthcare professional before incorporating it into your wellness routine.

Your rebirth begins today. Explore Kóre Labs' full range of adaptogens and start your journey towards optimized health.

References

1. Mikolai J, Erlandsen A, Murison A, Brown KA, Gregory WL, Raman-Caplan P, & Carson LJ. (2009). In vivo effects of Ashwagandha (Withania somnifera) extract on the activation of lymphocytes. Journal of Ethnopharmacology, 123(1), 160-164. https://pubmed.ncbi.nlm.nih.gov/19446758/
2. Bhat J, Damle A, Vaishnav PP, Albers R, Joshi M, & Banerjee G. (2012). In vivo enhancement of natural killer cell activity through oral administration of a standard extract of Withania somnifera. Phytotherapy Research, 26(12), 1833-1837. https://pubmed.ncbi.nlm.nih.gov/22467554/
3. Auddy B, Hazra J, Mitra A, Abedon B, & Ghosal S. (2008). A Standardized Withania Somnifera Extract Significantly Reduces Stress-Related Parameters in Chronically Stressed Humans: A Double-Blind, Randomized, Placebo-Controlled Study. Journal of American Nutraceutical Association, 11(1), 50-56. Link
4. Tharakan A, Shukla H, Benny IR, Tharakan M, George S, & Koshy S. (2021). Immunomodulatory Effect of Withania somnifera (Ashwagandha) Extract—A Randomized, Double-Blind, Placebo-Controlled Trial with an Open-Label Extension on Healthy Participants. Journal of Clinical Medicine, 10(16), 3644. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8397213/