All About Ashwagandha: What It Is, How It Works & What the Science Says
Ashwagandha has gone from a traditional herbal preparation to one of the most recognisable supplements on the market.
Search for it today and you'll find everything from straightforward root powders to highly concentrated extracts carrying enormous-looking milligram claims. Alongside them come claims about stress, sleep, exercise, cognition, hormones and almost everything in between.
So what actually is Ashwagandha? Why are people taking it? And what does the evidence really say?
Here’s our guide.
What is Ashwagandha?
Ashwagandha, scientifically known as Withania somnifera, is a small shrub that has a long history of use in Ayurveda, the traditional medical system of India.
The plant belongs to the Solanaceae family, the same botanical family that includes tomatoes, potatoes and aubergines.
Its roots are particularly associated with traditional use and remain one of the principal parts of the plant used in modern Ashwagandha supplements.
Today, you'll commonly find Ashwagandha sold as ground root powder, capsules or concentrated extracts.
It's also frequently described as an adaptogen. This is a broad term used for substances proposed to help the body adapt to physical or psychological stressors. While it's become an extremely popular term in the wellness industry, it shouldn't be mistaken for a specific medical effect or guarantee of what taking Ashwagandha will do.
Why has Ashwagandha become so popular?
Modern life has given Ashwagandha a rather different audience from its traditional one.
Interest has grown alongside wider conversations around stress, sleep, recovery and finding sustainable ways to manage demanding lifestyles.
That has also attracted scientific attention. Researchers have investigated Ashwagandha preparations in areas including stress, anxiety, sleep, cognitive function and physical performance.
However, there's an important distinction between “research has investigated this” and “this effect has been conclusively demonstrated.”
Different studies use different Ashwagandha preparations, concentrations, doses, populations and durations. Many trials are relatively small, and results obtained with one particular extract cannot automatically be applied to every Ashwagandha supplement.
That's why we think the interesting question isn't simply “Does Ashwagandha work?”
It's what does the evidence actually show?
What does the science say about Ashwagandha?
Stress and anxiety
Stress is probably the area most closely associated with modern Ashwagandha research.
A 2024 systematic review and meta-analysis examined nine randomised controlled trials involving 558 participants. The researchers reported improvements in measures of perceived stress and anxiety and reductions in serum cortisol compared with placebo. They nevertheless concluded that further information was required, particularly around longer-term safety. PubMed
Another meta-analysis published in 2022 also reported improvements in stress and anxiety, but importantly rated the certainty of evidence as low and found substantial differences between studies. PubMed
A larger 2026 review of 22 studies likewise reported promising results across several mental-health outcomes while calling for better-quality trials to resolve the considerable variation in the existing research. PubMed
The sensible conclusion therefore isn't that Ashwagandha is a proven treatment for stress or anxiety. There is promising clinical evidence, particularly around stress, but important uncertainty remains. The US National Center for Complementary and Integrative Health (NCCIH), for example, currently describes evidence for stress as supportive for some preparations while considering the evidence around anxiety less clear. NCCIH
Sleep
Ashwagandha has also been studied in relation to sleep.
A systematic review and meta-analysis of five randomised controlled trials involving 400 adults found a small but statistically significant improvement in overall sleep compared with placebo.
Interestingly, the effect was more pronounced among people with insomnia and in studies lasting eight weeks or longer. However, the researchers also highlighted the limited amount of long-term safety data available. PubMed
If you're interested in exploring our sleep supplement, find the product page here.
Exercise and physical performance
Ashwagandha has increasingly appeared in the sports-nutrition world too.
A 2026 systematic review and meta-analysis covering 13 trials and 599 participants found an average improvement across exercise-performance measures, with the most consistent evidence appearing in aerobic endurance. However, results weren't uniform and the authors described evidence around several other performance measures as uncertain or sparse. PubMed
So although this is an interesting developing area of research, Ashwagandha shouldn't be treated as a substitute for the things we know drive physical performance: appropriate training, nutrition, recovery and sleep.
Cognition
Cognition is another emerging area.
A 2026 systematic review covering 20 studies reported improvements across measures including memory, attention and processing speed. PubMed
It's an interesting direction for future research, but as with other proposed benefits, differences between formulations, populations and study designs matter. More research will help establish how meaningful and reproducible these effects are.
How might Ashwagandha work?
This is where things get particularly interesting from a biochemical perspective.
Ashwagandha isn't a single active molecule. The plant contains numerous naturally occurring compounds, including a group known as withanolides.
Withanolides are steroidal lactones that have become particularly important in Ashwagandha research and supplement standardisation.
Researchers have proposed several biological pathways that could contribute to observed effects of Ashwagandha preparations, including interactions with physiological systems involved in the stress response.
But proposed mechanism isn't the same thing as demonstrated clinical benefit.
Laboratory experiments can tell us fascinating things about what a compound does to a cell, receptor or signalling pathway. What ultimately matters for somebody taking a supplement is whether those mechanisms translate into meaningful effects in humans — which is why controlled clinical research remains so important.
Ashwagandha root powder vs extract: what's the difference?
This is one of the easiest areas of the supplement market to misunderstand.
Ashwagandha root powder is produced from the root itself. If a capsule contains 500mg of Ashwagandha root powder, there is 500mg of that root powder in the capsule.
Ashwagandha extracts are different. Components of the plant are extracted and concentrated, and products may be standardised to contain a particular concentration of compounds such as withanolides.
Neither approach is inherently “better”. They're simply different preparations.
This also means their milligram numbers aren't directly comparable.
A concentrated extract may contain considerably less physical material while providing a concentrated amount of particular constituents.
You may also encounter products advertising figures such as “5,000mg equivalent”. This can refer to the quantity of starting plant material represented by an extract rather than 5,000mg of material physically being inside the capsule.
That's why it's worth looking beyond the biggest number on the front of the bottle.
How much Ashwagandha should you take?
There's no single scientifically established dose that applies to every Ashwagandha product.
Research has used different doses depending on the preparation being investigated. A few hundred milligrams of a concentrated, standardised extract isn't necessarily comparable with the same weight of ordinary root powder.
That makes blanket claims such as “the scientifically proven dose of Ashwagandha is X mg” potentially misleading.
Instead, consider the specific preparation you're using and follow the product's directions.
Moderaci Ashwagandha contains 500mg of Ashwagandha root powder per capsule, with a recommended serving of one to two capsules daily.
That means you're getting exactly what the number suggests: 500mg of root powder from one capsule or 1000mg from two.
When should you take Ashwagandha?
There isn't a universally established “correct” time of day to take Ashwagandha.
For most people using a conventional supplement, following the manufacturer's directions and establishing a routine is more practical than worrying about finding a perfect minute of the day.
Some people prefer taking supplements with breakfast because they're easier to remember. Others incorporate them into an evening routine.
Moderaci Ashwagandha can be taken as one to two capsules daily, preferably with a meal.
Is Ashwagandha safe?
Natural doesn't automatically mean risk-free.
Ashwagandha appears to be tolerated by many people over the short periods studied, but long-term safety is less well established. Reported adverse effects can include stomach upset, diarrhoea, vomiting and drowsiness. Rare cases of liver injury have also been associated with Ashwagandha supplements. NCCIH
Ashwagandha should be avoided during pregnancy and breastfeeding. NCCIH also advises against its use around surgery and in people with certain autoimmune or thyroid disorders. Potential interactions include medicines used for diabetes, blood pressure, immune suppression, seizures and thyroid conditions, as well as sedatives. NCCIH
If you're taking medication, have an existing health condition, are preparing for surgery or aren't sure whether Ashwagandha is appropriate for you, speak to an appropriate healthcare professional before taking it.
Supplements should complement the foundations of health rather than replace medical care, a varied diet, sleep or other healthy habits.
How do you choose an Ashwagandha supplement?
The Ashwagandha shelf can be surprisingly difficult to navigate.
Rather than automatically choosing whichever product displays the largest number, look at what you're actually buying.
Check whether the product uses root powder, an extract, or a combination of plant parts. If it's an extract, look at its concentration and whether it's standardised. Check how the advertised strength has been calculated and how much material is actually present per capsule.
Then consider the rest of the product: does it contain other active ingredients? What is the capsule made from? Where is it manufactured? Are the directions and ingredient quantities clearly stated?
Transparency makes comparison considerably easier.
A simple product doesn't need a complicated label.
The Moderaci approach to Ashwagandha
We decided to keep ours simple.
Each Moderaci Ashwagandha capsule contains 500mg of Ashwagandha root powder in a plant-based HPMC capsule.
No enormous extract-equivalent number on the front. No unnecessarily complicated blend.
The 500mg capsule also gives you flexibility. Take one capsule for 500mg or two for 1000mg according to the recommended serving, rather than being locked into a single larger serving.
Each bottle contains 90 capsules, is manufactured in the UK and comes packaged in protective amber glass.
500mg per capsule. 90 capsules. Up to 90 days' supply.
Click the image below to explore Moderaci Ashwagandha today:
Because our approach to supplements reflects our wider philosophy:
A note from Moderaci
Supplement science isn't static.
New studies are published, evidence develops and scientific conclusions can change. We aim to update our educational content as the evidence develops and distinguish between interesting preliminary findings and conclusions supported by stronger clinical evidence.
This article is for general educational purposes and isn't intended to diagnose, treat or prevent disease or replace individual medical advice.
Last reviewed: October 2026
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