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Last updated November 16, 2019. 9 minute read

Ashwagandha benefits that have been proven by research

Ashwagandha gets its potent medicinal power from withanolides, naturally occurring steroidal lactones that are found in the root, but they need to be absorbed and pass through the intestinal wall to confer their benefits.

Linnea Zielinski Written by Linnea Zielinski
Reviewed by Dr. Mike Bohl, MD, MPH

The practices of Ayurveda, a traditional form of Indian medicine, have been around for centuries, but some of its hallmark treatments are only now gaining recognition in the United States. One of those is ashwagandha or Withania somnifera, also called Indian ginseng or winter cherry. This plant is an adaptogen, a family of medicinal plants such as herbs and roots popular in alternative medicine that help the body adapt to or deal with all kinds of stressors, from physical to mental. (Other popular adaptogens include American and Siberian ginseng, some fungi like Cordyceps, and Rhodiola rosea.) And we really are some of the last people catching on; ashwagandha has long been an essential herb of Ayurvedic, Indian, and African traditional medicine, which use both the roots and berries of the plant for treatments.

So why should your modern routine take a cue from these older wellness traditions? Although modern science still has a bit of catching up to do about these traditional treatments, the research does look promising. Like many other adaptogens, the potential health benefits extend from your brain to your blood sugar levels. Here’s what you need to know about ashwagandha and why it might be worth taking:


  • Ashwagandha is a plant that has been used for centuries in Ayurvedic medicine
  • Considered an adaptogen, it may help your body deal with mental and physical stressors, from anxiety to inflammation
  • Human studies show that the herb can increase testosterone production, boost sperm health, and even increase muscle size and strength in certain people
  • Ashwagandha is generally well-tolerated and widely available

Ashwagandha benefits

Ashwagandha root is considered a drug of “Rasayana”, a Sanskrit word that translates to path of essence and a practice of Ayurvedic medicine that refers to the science of lengthening lifespan. Many of its health benefits live up to this centuries-old reputation, but there is a catch here. In order for you to reap the health benefits of ashwagandha, like reduced cortisol levels and improved heart health, you need to be absorbing it properly. Ashwagandha gets its potent medicinal power from withanolides, naturally occurring steroidal lactones that are found in the root, but they need to be absorbed and pass through the intestinal wall to confer their benefits.

Reduce blood sugar

Powder made from ashwagandha root was able to lower blood sugar a similar amount as an oral diabetes medication in patients with type 2 diabetes, one very small study found (Andallu, 2000). Another also found effects on blood sugar levels, noting significant differences in fasting blood glucose between patients taking high-dose ashwagandha and those given a placebo (Auddy, 2008). The second found that the effects were dose-dependent: the larger the dose of the adaptogenic root, the larger the reduction in blood sugar levels. Researchers think this is because of how it acts on cortisol, which plays a role in regulating blood sugar.

Reduce cortisol levels (stress)

Stress on our bodies is more than what most of us think of when we talk about stress. For our bodies, stress can be emotional, psychological, or physical. But whichever stress you’re thinking of, it involves cortisol. You probably know cortisol as the stress hormone, which gets the nickname because our adrenal glands release it in response to stress. (For the record, some cortisol is not just good but vital for get-up-and-go reactions like waking up and having the energy to go about your day.) 

One study that gave participants a high-dose of ashwagandha root extract found that, compared to a placebo, it significantly reduced serum cortisol levels (Chandrasekhar, 2012). The participants of this study also reported a better quality of life because their perceived stress levels diminished. And another clinical trial gave employees who had experienced at least 6 weeks of moderate to severe anxiety high-dose ashwagandha and found that, along with several other interventions, it significantly improved mental health, concentration, energy levels, social functioning, vitality, and overall quality of life (Cooley, 2009).

It’s important to note that while this may help you feel less stressed at work to psychological stressors like an aggressive boss, it also helps with things your body sees as stressors like low blood sugar. Chronically elevated cortisol levels can be associated with elevated blood sugar levels and weight gain.

Treat arthritis

Although more research in humans need to be done, preliminary studies suggest that ashwagandha can help fight inflammation, making it a potentially powerful treatment for rheumatoid arthritis (RA). The root’s use as an anti-inflammatory goes back a long time. Ayurvedic medicine would mash the root into a paste that was applied to ulcers and caruncles as a pain reliever as well as to joints to ease inflammation, and a preliminary study backs up the practice (Singh, 2011). A small study found that, in combination with another Ayurvedic treatment for arthritis called Sidh Makardhwaj, ashwagandha powder eased swollen and painful joints in people with RA. More research needs to be done to confirm the findings.

Ashwagandha is also good at fighting other sources of inflammation. Tea made with withania somnifera and four other Ayurvedic herbs raised levels of natural killer (NK) cells in humans in one study (Bhat, 2009). These immune cells fight infection, which is one potentially source of inflammation. Another found that it decreased C-reactive protein (CRP), which is a very nonspecific marker of inflammation in the body. In fact, CRP was decreased by approximately 36% in participants in one study with just a twice daily dose of 250 mg of ashwagandha extract (Auddy, 2008).

Boost testosterone and improve fertility in men

Sperm count and motility increased in infertile men treated with ashwagandha powder in one study that included 75 fertile and 75 infertile men, and their oxidative stress, an imbalance between damaging free radicals and health-boosting antioxidants in the body, also decreased (Ahmad, 2010). Subjects’ testosterone levels also increased. But another small study is especially promising for men struggling with infertility (Mahdi, 2011). Men given ashwagandha for stress saw decreased stress levels, increased antioxidants in the blood, and improved sperm quality. In fact, by the end of the study, the partners of 14% of the men had become pregnant.

May increase muscle mass and strength

One of the longest-recognized effects of ashwagandha is its ability to increase strength and energy. In fact, the word ashwagandha is Sanskrit for “smell of the horse,” and references the herb’s unique smell as well as its ability to increase strength. (Don’t worry, you can side-step the smell issue by opting for capsules over loose powder.) Participants in one study designed to assess tolerability of the Ayurvedic herb showed positive composition and strength changes over 30 days (Raut, 2012). Enough to show it was worth devoting a study solely to how ashwagandha could help in these areas.

Although it was a small study, another showed that supplementing with ashwagandha may prove beneficial to those on a weight lifting regimen (Wankhede, 2015). At the end of the 8 week study, participants taking the supplement had increased their bench press by 176% more than those taking the placebo. Their strength gains on leg extension also outpaced their placebo-taking counterparts and they gained significantly more muscle size and lost more body fat.

Prevent loss of brain function

The “youth giving” properties of ashwagandha don’t just apply to your physical aptitude. Preliminary studies done on animals and in test tubes suggest it also extends to boosting your mental abilities and brain function. Though the practice of using ashwagandha for brain health is a long Ayurvedic practice, research in humans is lagging behind. Reaction time and cognitive function improved significantly in men put on a regimen of ashwagandha versus placebo in one small study (Pingali, 2014). Memory and information processing were also increased in participants of another study that looked specifically at effects in people with mild cognitive impairment (MCI) (Choudhary, 2017).

Although there are animal studies that show great promise for ashwagandha as a treatment for diseases like Parkinson’s and Alzheimer’s, more research needs to be done specifically in humans to see if the benefits are the same. The studies suggest that this herb can potentially help brain cell formation (Kuboyama, 2009) and communication and protect the brain (Jayaprakasam, 2010) against beta-amyloid, a plaque that causes cell damage and death and plays a role in the development of Alzheimer’s. But again, we cannot yet say that this holds true in humans until more research is done.

Improve heart health

One area where we do have solid human research is in the area of heart health. Withania somnifera appears to lower (Raut, 2012)both total and LDL cholesterol and serum triglycerides (Agnihotri, 2013), the main building blocks of body fat in humans, in certain people with consistent use. A very small study found the same, noting decreases in serum triglycerides and cholesterol, LDL cholesterol, and VLDL (very low density lipoproteins) cholesterol in its subjects after 30 days of use (Andallu, 2000).

May stop cancer growth

This is hands down one of the most exciting potential effects of withania somnifera. First things first, though: There’s currently no human research that suggests ashwagandha has anti-cancer properties, but animal and test-tube studies are worth mentioning because they’re so promising. The programmed death of cancer cells (or any other cells) is called apoptosis, and one study found that withaferin, a compound in the Ayurvedic herb, makes cancer cells less resistant to apoptosis as well as disrupting their growth (Nishikawa, 2015). And animal studies have found these properties hold true for multiple types of tumors, making it a potential treatment for lung (Senthilnathan, 2006), breast (Khazal, 2014), ovarian (Kakar, 2014), brain (Chang, 2016), prostate (Nishikawa, 2015), and colon (Muralikrishnan, 2010) cancers. In mice, this root seems especially effective. Ovarian tumors in mice reduced by 70–80% (Kakar, 2014) when treated with withaferin alone or in combination with an anti-cancer drug. We need to confirm these findings with human studies before saying it can do the same to our tumors, but it’s a hopeful first step.

Widely available and safe for most people

One of the most amazing parts of this adaptogen is the relatively low rate of side effects noted across many different clinical trials. One participant in a study on withania somnifera dropped out after experiencing increased appetite and libido as well as vertigo (Raut, 2012). But there are groups of people who shouldn’t take it, especially not without talking to a healthcare professional first. 

Pregnant women and breast-feeding moms should avoid ashwagandha. And people with an autoimmune disease—such as Hashimoto’s, rheumatoid arthritis, or lupus—need to consult with a medical professional before starting a supplement regimen. Also, talk to a healthcare practitioner if you’re on thyroid medication. Ashwagandha may impact lab results that test thyroid function. It’s also part of the nightshade family, so those following a diet that eliminates this group of plants that includes tomatoes, peppers, and eggplants should avoid taking this supplement.

Ashwagandha supplements are readily accessible in health stores, supplement shops, and online. Just choose a product from a company you trust as ashwagandha is not regulated by the FDA.