Few supplements have had quite the run ashwagandha has had over the past several years. It's in gummies, powders, coffee blends, and capsules, promoted as an easy way to feel calmer and more resilient in a busy life. It also happens to be one of the oldest herbs in Ayurvedic medicine, used for thousands of years in India for exactly that purpose.
Lately though, ashwagandha has been getting attention of a different kind. Food safety authorities in several European countries, including Denmark, France, and the Netherlands, have started reviewing it more closely, and Denmark has gone as far as restricting it in food supplements altogether. So is this beloved herb actually risky, or is it a case of caution catching up to popularity? Let's look at both sides.
What ashwagandha actually is
Ashwagandha comes from the root, and sometimes the leaves, of Withania somnifera, a small shrub native to India, the Middle East, and parts of Africa. Its calming reputation is generally credited to a group of compounds called withanolides, which researchers believe interact with the body's stress response system, though the full mechanism is still being worked out. In Ayurvedic tradition it's classified as a rasayana, a type of restorative tonic meant to be taken over time rather than as a quick fix, which is a slightly different mindset than how many people reach for it today.
Not all extracts are the same
Commercial ashwagandha comes in a range of forms, and this matters more than it might seem. Standardized extracts like KSM-66 and Sensoril are the most heavily studied in clinical trials, each processed slightly differently and concentrated to a defined level of withanolides. Less standardized products can vary quite a bit in strength, which is part of why comparing "ashwagandha" across brands isn't always an apples-to-apples exercise.
The evidence for stress and anxiety
This is genuinely where ashwagandha's reputation holds up best. Several recent meta-analyses have pooled the growing number of clinical trials, and the pattern is fairly consistent.
One 2024 meta-analysis of nine randomized trials involving 558 people found a meaningful reduction in perceived stress, anxiety scores, and cortisol levels compared to placebo. A separate, larger meta-analysis of fifteen trials with 873 participants echoed this, finding significant drops in both anxiety and cortisol, a hormone commonly used as a biological marker of stress. Interestingly, that same review found no real improvement in overall quality of life, a useful reminder that feeling less stressed on a questionnaire doesn't automatically translate into every area of daily life improving too.
Beyond stress relief
Ashwagandha has also been studied for sleep quality, exercise performance, and, in men, testosterone and fertility markers, with some encouraging smaller trials in each area. These uses are less thoroughly researched than the stress and anxiety evidence, so it's fair to treat them as promising side benefits rather than headline claims.
Why regulators are paying closer attention
Here's the part of the story that's genuinely worth understanding properly, since it's a real, current safety conversation rather than internet speculation. Over the past few years, a small but growing number of case reports have described liver injury in people taking ashwagandha supplements, including cases of jaundice and elevated liver enzymes that improved after stopping use. Other reports have raised concerns about effects on thyroid hormone levels, particularly in people who already have a thyroid condition.
In response, Denmark has restricted ashwagandha in food supplements, while Dutch and French food safety authorities have advised against its use in specific groups, including people with thyroid, liver, or heart conditions, pregnant women, and people taking sedative medication. The UK's Food Standards Agency has asked its expert toxicology committee to formally review the evidence and determine a safe exposure level.
It's worth adding some balance here too. Several broader safety reviews and larger analyses of clinical trial data have found no consistent signal of liver or thyroid harm at typical doses, and the herb has a genuinely long history of traditional use spanning thousands of years without this kind of concern being raised. One recent AI-assisted review of the published literature found that the vast majority of studies mentioning ashwagandha reported no toxicity concerns at all, with the small number of red flags concentrated mostly around cytotoxicity research related to cancer cells rather than everyday supplement use. The most likely explanation is that ashwagandha is safe for most people at reasonable doses, while carrying a real, if uncommon, risk for certain groups, which is exactly the kind of nuance that's easy to lose in headlines either praising or condemning a popular supplement.
Who should be extra cautious
Based on the current concerns being investigated, a bit of extra caution makes sense for:
- People with an existing thyroid, liver, or heart condition
- Pregnant women, since ashwagandha may affect hormone levels
- People taking sedatives, thyroid medication, or immunosuppressants
- Anyone noticing symptoms like unusual fatigue, dark urine, yellowing skin, or persistent nausea while using it, who should stop and see a doctor
For everyone else, most clinical trials to date have reported only mild, temporary side effects like drowsiness or an upset stomach.
Common questions
Does ashwagandha actually reduce stress? The clinical evidence here is some of the stronger evidence among popular adaptogens, with multiple meta-analyses showing real reductions in perceived stress, anxiety scores, and cortisol.
Why is ashwagandha suddenly controversial in Europe? A rise in case reports of liver injury and thyroid effects has prompted several countries to review its safety more closely, leading to restrictions in Denmark and cautionary advice in others. It reflects growing scrutiny rather than a sudden change in the herb itself.
How long does it take to notice an effect? Most clinical trials measuring stress and anxiety used eight weeks of daily use before assessing results, so it's generally not a same-day effect.
Is it safe to take long-term? This is genuinely one of the open questions researchers are still working on, since most trials only run for a few months. If you're considering long-term use, checking in with a healthcare provider periodically is a sensible precaution.
So, where does this leave you?
Ashwagandha remains one of the better-researched adaptogens for stress and anxiety, with real, repeatable clinical evidence behind that specific use. At the same time, it's genuinely a good moment to take the emerging safety conversation seriously rather than dismiss it, particularly if you fall into one of the higher-risk groups regulators have flagged. For most healthy adults without those risk factors, current evidence suggests it can be used sensibly and short to medium term, ideally with a standardized extract and a bit of attention to how your body responds.
As with any popular supplement caught between enthusiasm and emerging caution, the smartest approach is neither blind trust nor outright avoidance, but an informed one, ideally with a healthcare provider in the loop if you have any underlying health conditions.
Sources
- Effects of Ashwagandha Supplements on Cortisol, Stress, and Anxiety Levels in Adults: A Systematic Review and Meta-Analysis. BJPsych Open: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12242034/
- Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis. PubMed: https://pubmed.ncbi.nlm.nih.gov/39348746/
- Regulatory update: Spotlight on international authorities' response to ashwagandha safety concerns. Nutrition Insight: https://www.nutritioninsight.com/news/regulatory-update-spotlight-on-international-authorities-response-to-ashwagandha-safety-concerns.html
- Evaluating the Safety of Ashwagandha as a Food Additive: A Focus on Reproductive, Thyroid, and Immune System Effects. PubMed: https://pubmed.ncbi.nlm.nih.gov/41454545/
- Herb-Induced Liver Injury by Ayurvedic Ashwagandha as Assessed for Causality by the Updated RUCAM. Available via PMC: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10459262/
This article is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare provider before starting any new supplement.