Ashwagandha: Benefits, side effects, and safety concerns

Ashwagandha is getting a lot of attention from wellness-focused consumers. But can it really calm your anxious nerves or help you sleep more soundly, as proponents claim?

This herbal remedy has been used in traditional Indian (Ayurvedic) medicine for thousands of years. And there’s evidence emerging from studies of ashwagandha that’s encouraging. “Some of the findings from research line up quite well with traditional use cases,” says Dr. Jay Luthar, an integrative physician with Harvard-affiliated Mass General Brigham.

But ashwagandha isn’t a cure-all — and it may not be right for everyone. Here’s a closer look at when it may be helpful, for whom, and, if it is appropriate for you, how to work it into your wellness routine.

What is ashwagandha?

Ashwagandha is an evergreen shrub grown in Asia, Africa, and Europe. The plant has been used as an herbal remedy for centuries in Ayurvedic medicine, which aims to help the body and mind maintain a state of balance. In recent years, ashwagandha has gained popularity in the United States. Some people use the remedy to relieve stress, anxiety, and low energy.

In Ayurvedic medicine, ashwagandha root is dried and ground into a powder and stirred into warm cow’s milk. In the U.S., supplements, which include ashwagandha powder, liquids, capsules, and gummies, contain ashwagandha roots and leaves or their extracts.

Ashwagandha’s name comes from its scent. Traditionally, the roots were thought to smell like a wet horse. In Sanskrit, “ashwa” means horse and “gandha” means smell. Ashwagandha sometimes goes by other names too. Two common ones are winter cherry and Indian ginseng.

What does ashwagandha do?

Ashwagandha is considered to be an adaptogen. “These are compounds that appear to increase the body’s overall resistance to stress. They work by turning the body’s stress-response pathways up or down,” explains Dr. Luthar. Adaptogens may activate the body’s defense systems to help these systems handle stress.

Some evidence suggests that ashwagandha affects levels of the stress hormone cortisol. This may help regulate the body’s cardiovascular, nervous, and immune systems. Ashwagandha’s effects are thought to come from withanolides, compounds that seem to affect pathways that regulate inflammation, interactions between the nervous system and the endocrine (hormone-producing) system, and the body’s response to stress.

What are the benefits of ashwagandha?

Some of ashwagandha’s traditional uses within Ayurvedic medicine are supported by research studies. That’s especially true for things like stress management and better sleep.

However, not all of the claims about ashwagandha are backed by evidence. Here’s a closer look at how this herb may be helpful and where more studies are needed.

Stress and anxiety. Some research suggests that ashwagandha might help reduce feelings of stress and anxiety. In a randomized trial lasting one month, people who took ashwagandha capsules daily reported better well-being. Many said that they had more energy and focus. They reported sleeping better, too.

Other findings have suggested that ashwagandha lowers blood levels of the stress hormone cortisol. Most clinical trials have used doses ranging from 125 to 600 milligrams (mg) per day, according to the National Institutes of Health. Higher doses haven’t been studied as closely.

Sleep. There’s less research on ashwagandha and sleep. But a handful of small trials suggest that the remedy could be beneficial. In one study, participants who took 120 mg of ashwagandha extract daily for six weeks had greater improvements in sleep compared with those who took a placebo.

Another trial looking at adults with insomnia showed similar results: compared with those who got a placebo, the ashwagandha users fell asleep faster, had better sleep quality, and felt more alert when they woke up.

Male fertility. Some limited evidence suggests that ashwagandha might enhance male fertility. An older review found that the herb was tied to an increase in testosterone levels and sperm quality after two to four months of use, but its impact on fertility was uncertain. Additional studies are needed to understand this potential effect more fully.

Other uses for ashwagandha

It’s possible that ashwagandha could have helpful effects beyond stress and sleep. Some proponents believe that the herb might be useful for

• improving cognitive function
• alleviating constipation
• lowering high blood sugar
• reducing inflammation
• improving joint health
• reducing menopause symptoms
• enhancing sexual health.

However, the potential of ashwagandha to provide these benefits remains unproven as research is extremely limited.

Ashwagandha side effects and safety concerns

Ashwagandha appears to be safe for short-term use for people who are generally healthy. However, data on use beyond three months are limited, so discuss ongoing use with your doctor.

Some people who take ashwagandha may have mild side effects. These can include loose stools, nausea, or drowsiness. In rare instances, ashwagandha has also been reported to cause liver injury, impaired liver function, or both.

Ashwagandha may also interact with medications used to treat

• anxiety
• autoimmune conditions
• diabetes
• high blood pressure
• seizures
• sleep
• thyroid disease.

Keep in mind that ashwagandha may not work for everyone. Many people find that the herb helps them feel calmer and less stressed. But anecdotally, some people report feeling more stimulated or anxious. So, pay attention to how you feel after taking it — and stop if you don’t find it helpful.

Who should not take ashwagandha?

Ashwagandha may have negative health effects for certain people. You shouldn’t take it if you

• are pregnant or breastfeeding
• have a thyroid condition
• have prostate cancer
• have an autoimmune condition
• take medications for certain conditions, including diabetes, high blood pressure, sleep, anxiety, or seizures.

Should you try ashwagandha?

As you should before taking any new supplement, consult your doctor before taking ashwagandha. Like other herbal remedies, ashwagandha may work best as part of a bigger plan to address the root cause of your stress. “It’s a tool, but I’d never say that it’s the one thing a person needs. We should also look at their sleep habits, eating patterns, exercise, and whether they may need psychotherapy or medication,” Dr. Luthar says.

One other thing to remember: herbal supplements aren’t closely regulated. If you choose to take ashwagandha, make sure the product you buy is verified by a third-party seal. Look for one by a certifier like USP, NSF International, or ConsumerLab.

Frequently asked questions

How much ashwagandha can you take?

Most studies have looked at ashwagandha dosages ranging from 125 mg to 600 mg per day. The largest safety study to date used 600 mg per day. Some smaller studies have gone up to 500 mg to 600 mg twice per day, but these higher doses haven’t been studied as closely.

Ashwagandha appears to be well tolerated for up three months. A few small studies have looked at use up to 12 months. Beyond that, long-term data are limited. If you decide to take ashwagandha, you should decide with your doctor on how long to take it for. You should also decide together how you should be monitored to make sure that the ashwagandha continues to be beneficial for you and isn’t causing any harmful effects.

When is the best time to take ashwagandha?

Research on dosage timing is limited. So if you’re wondering when to take ashwagandha, experiment to see what works best for you. If you’re using it for sleep, try taking it close to bedtime. If you’re trying to manage stress or increase your focus during the day, you could try taking it earlier in the day.

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