Ashwagandha: What the Science Actually Says
Ashwagandha has quietly become one of the most talked-about herbs in the wellness world. It's in the adaptogen lattes, the "stress support" aisle and a great many social media routines. But it's not new — it's one of the oldest remedies in Ayurvedic medicine, with centuries of traditional use behind it.
So what is it, what does the research actually support, and why the surge in popularity now? Here's a measured look — including the parts the marketing tends to skip.
What Is Ashwagandha?
Ashwagandha (Withania somnifera) is a small shrub native to the drier regions of Asia, Africa and the Middle East. Its roots and orange-red fruit have been used for centuries in traditional medicine.[1]
The name itself is evocative: "ashwagandha" roughly translates to "smell of the horse" — partly a nod to the root's aroma, and partly, in traditional lore, to the strength it was said to impart. In Ayurvedic practice it's classed as a Rasayana, a category of tonics traditionally associated with vitality and rejuvenation.[1]
Traditional use is a good place to start a story — but it isn't evidence of effect, so let's turn to what modern research has actually looked at.
The Compounds Behind the Interest
Ashwagandha contains a family of naturally occurring compounds called withanolides, along with others such as sitoindosides and various alkaloids.[1] These are the constituents researchers are most interested in, and standardised extracts are often characterised by their withanolide content.
In laboratory and mechanistic studies, these compounds appear to interact with several biological pathways — including the body's stress-response system (the HPA axis) and signalling involved in relaxation.[1] That's the proposed why behind ashwagandha's best-studied use, which brings us to stress.
Ashwagandha and Stress: The Best-Studied Area
This is where the research is genuinely reasonable — and it's why ashwagandha is classed as an adaptogen, a term for substances traditionally used to help the body cope with stress.[1]
Several systematic reviews and meta-analyses have now pooled the randomised controlled trials in this area, and the overall pattern is fairly consistent: ashwagandha supplementation is associated with reductions in perceived stress and in levels of cortisol — the body's primary stress hormone — compared with placebo.[2,3] One meta-analysis of nine trials reported statistically significant improvements in perceived stress scores alongside a notable reduction in serum cortisol.[3]
It's worth keeping this in proportion, though. The trials are mostly short (typically 30–90 days), sample sizes are often modest, and results aren't perfectly uniform — at least one recent analysis found a clear cortisol reduction but a less consistent effect on perceived stress.[4] The honest summary: this is one of the more promising areas in the herbal-supplement literature, with real supportive evidence, while still being an area where researchers call for larger and longer trials.[2,4]
What About Everything Else?
Ashwagandha gets attached to a long list of claims online — covering mood, sleep, exercise and more. The evidence across these is uneven:
- Sleep has some supportive trial data and is an active research area, often linked to the same stress-modulating mechanisms.[1]
- Mood and cognition have preliminary human research, but it's earlier and less settled than the stress findings.[1]
- Many other circulating claims rest mainly on preclinical (cell and animal) studies, which are a reason to investigate further — not evidence of an effect in people.
The pattern is a familiar one in this series: a genuinely interesting herb whose strongest evidence sits in one area (stress), surrounded by a much larger cloud of claims that are earlier, weaker or purely preclinical. Reading past the headline matters.
Safety: The Part That Deserves Attention
Ashwagandha is generally well tolerated at typical doses, with mild side effects such as digestive upset or drowsiness reported in some people.[1] But there are some genuinely important cautions, and they're often glossed over:
- Pregnancy and breastfeeding. Ashwagandha is traditionally contraindicated in pregnancy and is generally advised against, as it may not be safe.[1]
- Certain health conditions and medications. Because it may affect the immune system, thyroid parameters, blood sugar and sedation, it can interact with some conditions and medications. Anyone in these categories should seek professional advice first.[1]
- Liver considerations. There have been case reports internationally of liver issues associated with some ashwagandha products, which is one reason quality, correct identification and professional guidance matter.
This isn't a reason for alarm, but it is a reason ashwagandha shouldn't be treated as automatically harmless just because it's a plant. "Natural" and "risk-free" are not the same thing.
Why Is It Gaining Popularity?
Several things have converged. Modern life is stressful, and interest in natural approaches to managing stress has grown sharply. Ashwagandha happens to be the adaptogen with some of the more supportive human trial data behind exactly that use, so it's ridden that wave. Standardised extracts have made it more consistent than older preparations. And the wellness world loves a compound with an ancient pedigree and a modern evidence base — ashwagandha offers both.
Common Myths
Myth 1: Ashwagandha is a proven treatment for a long list of conditions. Its strongest evidence is in stress and cortisol. Many other circulating claims are preliminary or preclinical.[2,3]
Myth 2: Because it's natural, it's completely safe. It has real contraindications — including pregnancy — and can interact with medications and conditions.[1]
Myth 3: All ashwagandha is the same. Products differ in the part of the plant used, extract standardisation and withanolide content, which is why research uses standardised extracts.[1]
The Bottom Line
Ashwagandha is one of the more interesting entries in the modern supplement story: an ancient herb whose headline use — helping the body cope with stress — is backed by a genuinely reasonable and growing body of human research, even as much of the wider hype around it outpaces the evidence.
As with everything in this space, the useful approach is neither dismissal nor breathless enthusiasm. It's a real herb with real activity, real research and real cautions — and, as always, decisions about whether it's right for you are best made with a healthcare professional who knows your circumstances.
References
- National Institutes of Health, Office of Dietary Supplements. Ashwagandha: Is it helpful for stress, anxiety, or sleep? — Health Professional Fact Sheet. Available at: https://ods.od.nih.gov/factsheets/Ashwagandha-HealthProfessional/
- Effects of Ashwagandha Supplements on Cortisol, Stress, and Anxiety Levels in Adults: A Systematic Review and Meta-Analysis. BJPsych Open. 2025. Available at: https://www.cambridge.org/core/journals/bjpsych-open/article/effects-of-ashwagandha-supplements-on-cortisol-stress-and-anxiety-levels-in-adults-a-systematic-review-and-metaanalysis/6F2D7847C1F64707F2034A45FD6CF0C0
- Arumugam V, Vijayakumar V, Balakrishnan A, et al. Effects of Ashwagandha (Withania somnifera) on stress and anxiety: A systematic review and meta-analysis. EXPLORE. 2024;20(6):103062. Available at: https://www.sciencedirect.com/science/article/abs/pii/S1550830724001691
- Albalawi AA. Dual impact of Ashwagandha: Significant cortisol reduction but no effects on perceived stress — A systematic review and meta-analysis. Nutrition and Health. 2025. Available at: https://journals.sagepub.com/doi/abs/10.1177/02601060251363647
This article is intended for general educational purposes only and does not constitute medical advice. Ashwagandha has contraindications — including pregnancy — and can interact with medications and health conditions. Individual health needs vary; please consult a qualified healthcare professional or pharmacist regarding your own circumstances before starting any new supplement.
