Ashwagandha is a popular herb in Ayurvedic medicine that's been used to promote overall well-being for thousands of years. In fact, it's known as Indian ginseng and has been gaining significant traction outside India. It's reported to have a wide range of benefits, including better sleep and improved memory. It's also used in the treatment of anxiety and stress, and some use it to help with athletic performance and even the treatment of menopausal symptoms.
But is there any scientific evidence to back up its traditional uses? I did some digging into the literature and came away pretty impressed by the evidence behind some of its uses. In this article, I'll go over the benefits of ashwagandha with the strongest evidence. At the end, I'll cover its safety profile and everything you need to know before incorporating it into your health routine.
Hi, I'm Dr. Leonid Kim, board-certified in Obesity and Internal Medicine, and I share the most up-to-date, evidence-based information on weight loss, metabolic health, and longevity. Let's get into it.
Ashwagandha for Stress and Anxiety
One of the most studied uses of ashwagandha is its effect on stress and anxiety. A recent systematic review and meta-analysis of 29 trials, published in May of last year, noted a significant effect on anxiety, as measured by the Hamilton Anxiety Rating Scale, a psychological questionnaire often used to rate the severity of a person's anxiety. However, the trials were limited by small sample sizes.
Another study worth highlighting is a double-masked, randomized, placebo-controlled clinical trial published in 2019 that examined the adaptogenic and anxiolytic effects of ashwagandha root extract. This study looked not only at overall perceived stress and anxiety levels, but also at participants' serum cortisol levels, a stress hormone that can lead to elevated blood sugar, weight gain, and depression. The study found a significant reduction in stress levels and in serum cortisol levels.
One thing to note is that this study also compared two doses of ashwagandha: a standard dose of 600 milligrams per day versus a lower dose of 250 milligrams per day. They found that even at the lower dose of 250 milligrams per day, there was a statistically significant reduction in stress levels, an improvement in serum cortisol levels, and improved sleep quality. However, improvement in anxiety was only seen in the group taking the higher dose of 600 milligrams per day.
These results were impressive, but the sample size was pretty small, at 60 people, and the study duration was only eight weeks, making it difficult to extrapolate these findings to a larger population or know whether the results would hold with longer follow-up.
Ashwagandha for Sleep
Given that increased stress and anxiety often lead to poor sleep and insomnia, it's not surprising that ashwagandha has also been studied for its effect on sleep. A 2021 meta-analysis of five randomized controlled trials, including 400 participants, found that ashwagandha extract has a beneficial effect on sleep in adults.
An important caveat is that only two of the trials included in this meta-analysis combined both subjective and objective sleep measurements, meaning only two studies used self-reported questionnaires alongside lab-based polysomnography. This test provides more objective data on sleep quality. Another important caveat is that there was little data on the effects of ashwagandha in older adults, so it's difficult to extrapolate these effects to that population.
Ashwagandha for Memory and Cognition
When it comes to memory and cognition, the evidence isn't as strong. Still, it includes a prospective, randomized, double-masked study of 50 adults showing that eight weeks of ashwagandha treatment led to significant improvements in both immediate and general memory. It also showed a general improvement in executive function, sustained attention, and information-processing speed in adults with mild cognitive impairment.
A follow-up systematic review of five clinical studies reported early evidence of cognitive benefits. However, this review was limited by a heterogeneous population that included adults with mild cognitive impairment, schizophrenia, schizoaffective disorder, and bipolar disorder.
Ashwagandha for Physical Performance
Another area of research has focused on ashwagandha's effects on physical performance, and the initial data are promising. A double-masked, randomized, placebo-controlled trial published in 2021 included 50 athletic adults, with half randomized to receive 300 milligrams of ashwagandha twice daily for 8 weeks. The group that received ashwagandha showed improvement in VO2 max, a marker of cardiorespiratory fitness, as well as improved recovery.
Another study specifically examined muscle strength and recovery in 57 adults, with half randomized to ashwagandha supplementation and the other half to a placebo. After eight weeks of resistance training, the group that took ashwagandha had significantly greater increases in muscle strength and size. The ashwagandha group also showed a significantly greater reduction in exercise-induced muscle damage, as indicated by stabilization of serum creatine kinase, as well as a greater decrease in body fat percentage.
Ashwagandha for Menopausal Symptoms
Lastly, some people promote using ashwagandha in the treatment of perimenopausal symptoms. A randomized, double-blind, placebo-controlled study published in 2021 included 100 women and found that taking 300 milligrams of ashwagandha twice daily was associated with improvements in hot flashes, night sweats, anxiety, and urogenital symptoms compared with placebo. The group treated with ashwagandha also showed a statistically significant increase in estradiol levels, which may help explain its benefits for menopausal symptoms, since menopause is the period when estradiol levels decline due to progressive ovarian impairment.
Safety Profile
When it comes to safety, none of these studies found any major adverse events, though most had pretty small sample sizes and short follow-up periods. A study published in 2021 examined the safety and tolerability of ashwagandha in 80 participants and found that administering up to 300 milligrams twice daily for 8 weeks did not result in any adverse effects, as assessed by hematologic and biochemical parameters.
Researchers also did not find any abnormalities in participants' liver or thyroid function, which is reassuring, since there are some case reports of liver damage associated with ashwagandha use.
Unfortunately, there's just no reliable long-term data on the safety of ashwagandha beyond eight weeks. Personally, given the small sample sizes and sparse long-term safety data, I would talk to your doctor before using ashwagandha, especially if you're taking prescription medications or other supplements, so that you can monitor for potential effects on your liver or interactions with other medications.
Conclusion
Ashwagandha has accumulated a surprising amount of credible evidence supporting several of its traditional uses, particularly for stress, anxiety, sleep, physical performance, and menopausal symptoms, with some promising early signals for memory and cognition as well. That said, the research base is still relatively young, built mostly on small trials with short follow-up periods, typically eight weeks or less.
Long-term safety data are limited, and while serious side effects appear rare, there are occasional case reports of liver-related issues. For most healthy adults, ashwagandha appears reasonably safe to try. Still, it's worth discussing with your doctor first, especially if you take other medications or supplements, so that any effects can be properly monitored.
FAQ
What is ashwagandha used for?
Ashwagandha is traditionally used in Ayurvedic medicine to promote overall well-being. Modern research has focused on its potential benefits for stress and anxiety, sleep, memory and cognition, physical performance, and menopausal symptoms.
Does ashwagandha actually reduce stress and anxiety?
Yes, evidence suggests it does. Multiple clinical trials show ashwagandha can reduce stress and serum cortisol levels, with anxiety improvements more consistently seen at higher doses (around 600 milligrams per day) compared to lower doses.
Can ashwagandha improve sleep?
Research suggests it can. A meta-analysis of five randomized controlled trials found a beneficial effect on sleep in adults. However, data in elderly populations and in studies using objective sleep measurements such as polysomnography remain limited.
Is ashwagandha helpful for exercise or muscle recovery?
Early studies suggest yes. Clinical trials have shown improvements in VO2 max, exercise recovery, muscle strength and size, and reduced exercise-induced muscle damage in adults taking ashwagandha alongside resistance training.
Is ashwagandha safe to take long-term?
Short-term studies, generally up to eight weeks, have not found major adverse effects on liver, thyroid, or blood parameters. However, reliable long-term safety data beyond eight weeks is lacking, and there are occasional case reports of liver damage associated with ashwagandha.
Should I talk to a doctor before taking ashwagandha?
Yes, especially if you take prescription medications or other supplements. Given the limited long-term safety data, a doctor can help monitor for potential liver effects or drug interactions.