Ashwagandha: Stress, Sleep and the Evidence Explained
Ashwagandha has gone from a little-known Ayurvedic herb to one of the most searched supplements in Australia. Social media is full of claims about stress, sleep and energy. So what has actually been tested, and what do Australians need to know about safety? This guide looks at the research, its limits, and the Therapeutic Goods Administration’s (TGA) current advice.
What is ashwagandha?
Ashwagandha is the common name for Withania somnifera, a small shrub in the nightshade family. It’s also called withania or Indian winter cherry. The root has been used in traditional Ayurvedic practice for centuries, where it’s described as a “rasayana”, a tonic herb.
The root contains a group of compounds called withanolides, along with alkaloids and other plant chemicals. Most modern research uses standardised root extracts, measured by their withanolide content.
An important point: extract, not tea
Almost every human trial of ashwagandha used concentrated root extracts in capsules, usually at 240–600 mg a day, often for eight weeks or more. Many used branded, standardised extracts. None of the studies below tested a cup of ashwagandha tea, and it’s not known how closely a herbal infusion matches those doses. Keep that in mind whenever you read a claim about ashwagandha.
Ashwagandha and stress
A 2022 systematic review and meta-analysis in Phytotherapy Research pooled randomised controlled trials of ashwagandha supplements for stress and anxiety (Akhgarjand et al., 2022). Compared with placebo, people taking the extracts reported lower scores on stress and anxiety questionnaires.
The authors also flagged limits. The trials were fairly small, they used different extracts, doses and questionnaires, and most ran for only a couple of months. They called for larger, longer studies before firm conclusions are drawn.
One of the individual trials gives a sense of what’s being tested. In an Australian study, 60 adults with mild self-reported stress took either 240 mg of a standardised extract or a placebo for 60 days (Lopresti et al., 2019). The extract group had a larger drop on a clinician-rated anxiety scale and lower morning cortisol and DHEA-S. But on another common questionnaire, the difference from placebo wasn’t statistically significant. Mixed results like this are typical of this field.
Ashwagandha and sleep
A 2021 meta-analysis in PLoS One looked at five randomised trials, with about 400 people in total, of ashwagandha extract and sleep (Cheah et al., 2021). It found a small but statistically significant effect on overall sleep, a little stronger in people with insomnia, and in trials using 600 mg a day or more for at least eight weeks.
“Small” is the key word. The authors judged the overall quality of evidence as limited and noted that more data are needed on safety.
What the research doesn’t show
It’s easy for small, promising results to become big promises online. At this stage, research doesn’t show that ashwagandha works for any medical condition, and it can’t replace advice or treatment from a health professional. If stress, anxiety or poor sleep is affecting your life, talk to your GP.
TGA safety advisory (February 2024)
On 22 February 2024 the TGA published a safety advisory on medicines and herbal supplements containing Withania somnifera (TGA, 2024). As at October 2026, this is the current advisory on the TGA website. The key points are:
- Products containing ashwagandha may cause sudden and potentially severe gastrointestinal symptoms in some people, such as severe nausea, vomiting and diarrhoea, sometimes after a single dose. The TGA noted 16 cases severe enough to need hospital care.
- In very rare cases, ashwagandha may be associated with liver injury. The TGA had received 12 reports of liver problems up to 5 February 2024. Seven had enough information to suggest liver injury that may have been caused by ashwagandha, and four of those needed hospital care. Most people recovered after stopping.
- Stop taking it immediately and seek medical advice if you notice yellowing of the skin or eyes, dark urine, nausea, vomiting, unusual tiredness, weakness, stomach or abdominal pain, or loss of appetite.
- If you have, or have had, liver problems, avoid medicines and herbal supplements containing ashwagandha.
The TGA says it’s continuing to monitor the evidence and may take further regulatory action, such as label warnings. Check the TGA website for any updates.
Who else should take care?
Beyond the TGA advice, ashwagandha is generally not recommended during pregnancy or breastfeeding. It may also interact with some medicines, including those for thyroid conditions, diabetes, blood pressure, the immune system and sedatives. If you take regular medication or have a health condition, check with your pharmacist or GP first.
The bottom line
Ashwagandha is one of the better-studied traditional herbs, and early trials of standardised root extracts on stress and sleep are interesting. But the studies are small and short, they used concentrated extracts rather than tea, and the TGA has flagged real, if uncommon, safety concerns. Treat bold online claims with caution, know the warning signs, and get personal advice before you try it.
This article is general information only and is not medical advice. It is not about any specific product. Talk to your GP or pharmacist about your own health. Safety information is current as at 24 October 2026; always check the TGA website for the latest advice.
References
- Akhgarjand C, et al. Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials. Phytother Res. 2022. https://pubmed.ncbi.nlm.nih.gov/36017529/
- Cheah KL, et al. Effect of Ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis. PLoS One. 2021. https://pubmed.ncbi.nlm.nih.gov/34559859/
- Lopresti AL, et al. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2019. https://pubmed.ncbi.nlm.nih.gov/31517876/
- Therapeutic Goods Administration. Medicines containing Withania somnifera (Withania, Ashwagandha): safety advisory. 22 February 2024. https://www.tga.gov.au/safety/safety-monitoring-and-information/safety-alerts/medicines-containing-withania-somnifera-withania-ashwagandha
