Ashwagandha’s purported immune-boosting properties have heightened its popularity amid the COVID-19 pandemic. But are these benefits backed by credible science?
What Is Ashwagandha?
Ashwagandha (Withania somnifera) is a simple evergreen shrub with light-green flowers and red-orange fruit. It is native to the dry, hot regions of the Middle East, northern Africa, and the Indian subcontinent.
It belongs to the Solanaceae, or nightshade, family. This makes it a relative of tomato, eggplant, and bell pepper plants. The root, leaves, and berries of ashwagandha have long been used in medicinal preparations.
The plant is particularly important to the ancient Indian medicine system, Ayurveda. Adherents refer to ashwagandha as the “King of Ayurvedic Herbs,” due to its claimed ability to treat a vast range of ailments.
In Sanskrit, ashwagandha means “the smell of a horse”—a nod to its equine aroma as well as the horse-like strength and stamina it’s said to impart to users.
Other supposed benefits include lowering blood sugar, boosting memory and cognitive function, and reducing triglyceride and cholesterol levels.
These benefits may come from the herb’s bioactive compounds, including:
- Alkaloids: Naturally occurring nitrogen-containing bases found in plants.
- Saponins: Bitter-tasting glycosides known to foam in water.
- Withanolides: Steroidal lactones that give ashwagandha its distinct flavor and odor (withaferin A, withanone).
8 Potential Health Benefits of Ashwagandha
Let’s take a closer look at the research surrounding ashwagandha benefits for health.
1. Reduced Stress and Anxiety
Ashwagandha is considered an adaptogenic herb, which means it may help limit the effects of stress on your body. One of the ways this might occur is through the hormone cortisol.
Your adrenal glands release cortisol in response to stress. This can be useful in “fight-or-flight” situations, as it provides you with a shot of glucose (energy) to prepare for action.
But when your cortisol levels remain too high for extended periods, it can cause harm to multiple body systems. Chronically high cortisol levels can lead to:
- High blood sugar
- High blood pressure
- Digestion problems
- Weight gain
Research suggests that ashwagandha could help lower cortisol levels.
A 2008 study showed that cortisol levels were significantly reduced (by up to 30%) in chronically stressed adults who took ashwagandha extract, compared to a control group.
In a 2019 study, published in the journal Medicine, researchers looked at 60 adults who reported high stress. Participants were randomly assigned to one of two groups: one taking 240 milligrams (mg) of ashwagandha daily and the other taking a placebo. The ashwagandha group saw greater reductions in cortisol and other measurements of stress and anxiety levels.
And in another study of 64 adults with chronic stress, those supplementing with ashwagandha reported a 70% reduction in anxiety and insomnia. The placebo group reported an 11% reduction.
Moreover, blood cortisol levels dropped by 27% in patients on ashwagandha, compared with 7.9% in those on the placebo.
2. Improved Male Fertility and Testosterone Levels
There’s some evidence that ashwagandha might positively impact testosterone levels and infertility in men.
In a 2010 study, 75 infertile men treated with ashwagandha root experienced improvements in sperm count and motility. They also showed higher blood levels of testosterone.
One pilot study evaluated the herb’s spermatogenic activity in 46 men with low sperm counts. Twenty-one subjects took 675 mg of root extract three times daily for 90 days; the other 25 followed the same protocol with a placebo.
The ashwagandha treatment significantly improved and regulated patients’ blood hormone levels relative to placebo treatment.
As well, among the ashwagandha group, researchers found a:
- One hundred sixty-seven percent increase in sperm counts
- Fifty-three percent increase in semen volume
- Fifty-seven percent increase in sperm motility
Finally, a 2011 study, published in Evidence-Based Complementary and Alternative Medicine, suggested that Withania somnifera improved semen quality in infertile men under psychological stress. In fact, 14% of the patients’ partners became pregnant following the three-month treatment.
However, despite their infertility, the men all had normal, healthy sperm at the outset of the study.
3. Potential Anti-Cancer Effects
Studies in rodents and in vitro have shown ashwagandha’s promise in stopping the growth of certain cancers.
A 2011 review highlighted one study examining the herb’s anti-tumor effect on CHO (Chinese hamster ovary) cells carcinoma. Results suggest ashwagandha root inhibited the cells’ colony-forming efficiency. Specifically, researchers said it blocked the cells’ growth while also preventing their attachment.
Other research reviewed found ashwagandha to be effective against lung tumors in mice.
Withania somnifera might also help trigger the programmed death of cancer cells, or apoptosis. Multiple studies point to the cell-toxic compound withaferin A in ashwagandha as the catalyst.
Scientists think withaferin A might work to lower apoptosis resistance in cancer cells. They also suspect it prompts cancer cell dysfunction by encouraging and regulating free radical development.
In a study published in the journal Frontiers in Physiology, researchers stated that withaferin A induced DNA damage in human oral cancer cells by generating free radicals. The authors wrote that the compound “selectively killed oral cancer cells with less toxic effects to normal oral cells.”
More research is necessary to determine if ashwagandha has the same anti-cancer effects in humans outside the lab.
4. Blood Sugar-Lowering Activity
People have used ashwagandha to help manage their diabetes since ancient times. And research, albeit limited, suggests our predecessors might have been onto something.
Diabetes is a metabolic disorder where the pancreas either doesn’t produce enough insulin or doesn’t respond to it properly. This creates abnormally high levels of sugar in the blood.
Test-tube, animal, and human studies have found that ashwagandha can reduce blood sugar levels.
An in vitro study of muscle cells showed Withania somnifera heightened insulin sensitivity and boosted insulin secretion. Researchers believed that withaferin A was at least partially responsible for the anti-diabetic effects.
In a 2008 study, researchers observed improvements in blood glucose levels, insulin levels, and insulin sensitivity in diabetic rats fed ashwagandha.
Meanwhile, a systematic review and meta-analysis of 24 studies, published in Phytotherapy Research, concluded that ashwagandha treatment in diabetes “significantly restored the altered levels of blood glucose, glycosylated hemoglobin, insulin, lipid profile, serum and oxidative stress markers with no safety concerns.”
5. Greater Muscle Strength and Mass
Ashwagandha may also be beneficial if you’re looking to gain muscle and better strength.
One study examined the effects of the root extract on muscle mass and strength in males performing resistance training.
For the study, scientists randomly assigned 57 men aged 18 to 50 years, with little experience in resistance training, to a treatment group or a placebo group.
The treatment group took 300 mg of ashwagandha root extract twice a day, while the control group consumed starch placebos. Both groups underwent resistance training for eight weeks, with baseline measurements taken at the beginning of the study and at the end of week eight.
Results showed that the ashwagandha group saw significantly greater increases in muscle strength (on the bench-press and leg-extension exercises) and muscle size (of the arms and chest).
In another study, researchers were evaluating the safety and tolerability of the herb in healthy adults. Participants took between 750 and 1,250 mg of ashwagandha daily over a 30-day period. Among other benefits, the subjects saw a significant increase in muscle strength after 30 days.
6. Boosted Cognitive Function and Memory
A couple of human studies have put ashwagandha’s long-touted benefits for memory and cognitive function to the test.
One placebo-controlled study recruited 50 adults with mild cognitive impairment. Researchers found that taking 300 mg of ashwagandha root extract twice daily significantly improved participants’ memory as well as their executive function, attention, and information processing speed.
The other study showed improvements in reaction time and a variety of cognitive tasks among healthy men who took two 250-mg capsules twice daily for two weeks.
Scientists have also investigated ashwagandha’s ability to protect nerve cells against degeneration in cellular and animal models.
A lab dish study, published in 2012, showed that the liquid extract strongly inhibited the formation of amyloid-beta fibrils. This occurs when normally soluble proteins clump together to form insoluble fibers that are hard to degrade. Their formation in the brain is one of the hallmarks of Alzheimer’s disease.
A similar PLoS ONE study found that ashwagandha extract reverses beta-amyloid-induced toxicity in human neuron cells.
And in an animal study, older mice administered Withania somnifera root extract saw a reversal in behavioral deficits, amyloid-beta peptide buildup, and other pathological features of Alzheimer’s disease.
7. Lower Triglyceride and Cholesterol Levels
In studying ashwagandha’s effects on stress and blood sugar levels, researchers have uncovered its potential to lower high levels of blood fats, including triglycerides and cholesterol.
In a study of adults with chronic stress, researchers reported that the group taking 250 mg of standardized extract twice daily saw an 11% decrease in triglycerides after 60 days. The group’s “bad” LDL (low-density lipoprotein) cholesterol was down by 17%, on average.
Significant decreases in triglycerides and LDL cholesterol were also seen in a very small study of 12 adults—six with type 2 diabetes and six with high cholesterol. For the 2008 study, scientists treated the subjects with powdered ashwagandha root for 30 days.
It’s important to note that the research in humans is very limited. Greater blood-fat reductions have been seen in animals.
8. Enhanced Immune Response
A growing number of people are turning to natural remedies like ashwagandha to boost their immunity during the COVID-19 pandemic.
The South Asian herb does appear to act as an immunomodulator. These chemical agents can alter the behavior of the immune system, most often in a positive way.
Ashwagandha, in particular, is thought to aid the immune system by suppressing pro-inflammatory response. This allows for a more effective immune response to potential pathogens.
Several studies have underscored ashwagandha’s impact on pro-inflammatory cytokines.
A 2017 study evaluated the immune-regulating effect of an ashwagandha-based formulation in the white blood cells of mice. Results showed that expression of the cytokines TNF-α (tumor necrosis factor), IL-1β (interleukin-1β), and MIP-1α (macrophage inflammatory protein-1 alpha) was significantly down-regulated.
In a placebo-controlled study, Withania somnifera root reduced TNF-α and interleukin-6 (IL-6) in fructose-fed rats. It also blocked the fructose-induced increases in glucose and insulin.
The findings suggested that the root normalized the rats’ high blood sugar by reducing inflammatory markers and improving insulin sensitivity, per the researchers.
Ashwagandha and COVID-19
Cytokines signal your immune cells to travel to the scene of an attack. Yet, having too many of them circulating at once can cause your body to attack itself. The phenomenon, called a cytokine storm, has been linked to severe COVID-19 cases.
Many have used this observation to peddle ashwagandha supplements as a cure-all. But while the above study outcomes are promising, keep in mind that there is no known cure for COVID-19 yet.
Building immunity is no doubt important. But it doesn’t happen with the pop of a pill. A healthy diet, regular exercise, and adequate sleep are also contributing factors.
Preventive measures are still the best ways to fight infection with the virus that causes COVID-19, including handwashing, mask-wearing, and social distancing.
Ashwagandha Uses and Dosages
Ashwagandha has traditionally been used to treat many of the conditions outlined above. However, more research is needed to confirm its effectiveness for these purposes, particularly larger, more rigorously designed studies in humans.
In existing clinical studies, scientists have used a wide range of dosages. A standard recommended dosage has not yet been set.
As such, how much ashwagandha to take and how often will depend on the condition you’re trying to treat. With stress, for example, dosages ranging from 240 to 600 mg daily have reduced symptoms.
Dosages of between 600 and 1,000 mg per day improved memory and cognitive function in some studies.
Ultimately, it’s best to seek a qualified naturopath or healthcare practitioner to help you determine the appropriate dosage for your needs.
You can purchase ashwagandha in capsule, powder, or liquid extract form. The supplement is widely available in major supermarkets, health food stores, and online retailers at various strengths.
Dried leaves and roots are also available for use in teas.
Ashwagandha Side Effects and Precautions
Ashwagandha is considered safe for most people when taken in smaller doses for up to three months. Some of the reported side effects with larger doses include:
- Upset stomach
Pregnant and nursing women should avoid using the herb altogether. Some evidence suggests it may cause miscarriages or premature labor, while safety data on breastfeeding women are lacking.
Ashwagandha may increase your immune response. This could potentially lead to an increase in symptoms if you have an autoimmune disease like multiple sclerosis, rheumatoid arthritis, or lupus. Check with your doctor whether supplementing is safe for you.
Due to possible adverse drug interactions, people with the following conditions should also consult their doctor before taking the remedy:
- Thyroid disease
- High blood pressure
Lastly, it’s important to remember that the U.S. Food and Drug Administration does not regulate herbal supplements like ashwagandha. Therefore, you should only purchase from a reputable, third-party-tested manufacturer. Certified organic and non-GMO supplements are ideal.
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