Last updated: October 2026
Most people tolerate ashwagandha well, and the most common side effects are mild: drowsiness, an upset stomach, nausea and loose stools. Rarely, it has been linked to liver injury and thyroid changes. Avoid it if you are pregnant or breastfeeding, have a thyroid, liver or autoimmune condition, are due to have surgery, or take regular medication.
Below: the common and rare side effects, what to know as a man or a woman, the “emotional numbness” question, who should avoid it, medicine interactions, where ashwagandha stands in the UK, and how to use it more safely.
Common ashwagandha side effects
Ashwagandha (Withania somnifera) is a root used in Ayurvedic practice for centuries and now one of the UK’s most popular supplements for stress. In studies, side effects are usually mild and similar to a placebo. The ones people report most are:
- Drowsiness or feeling sluggish, especially when taken in the morning
- An upset stomach, nausea or loose stools, more likely on an empty stomach
- Headaches
- Vivid dreams for some people
These usually settle if you lower the dose, take it with food or move it to the evening. Read our guide on when to take ashwagandha.
Less common and rare side effects
Liver injury (rare)
A small number of liver injury cases linked to ashwagandha supplements have been published, including case series from Iceland, the US and India. It is rare, and most people recovered after stopping, but stop straight away and see a doctor if you notice yellowing of the skin or eyes, dark urine, itching or pain in the upper right of your tummy.
Thyroid changes
Ashwagandha can raise thyroid hormone levels in some people, and there are case reports of an overactive thyroid. This matters most if you already have a thyroid condition or take thyroid medicine.
Hormonal effects
Ashwagandha can influence hormones, including testosterone and thyroid hormones. That is part of why some people take it, but it is also why regulators have been cautious about it.
Changes in mood
Most people take it to feel calmer, but a few report feeling flat, restless or more anxious. If your mood changes for the worse, stop taking it.
Ashwagandha side effects for women
- Pregnancy: avoid ashwagandha. There are long-standing concerns that high doses could increase the risk of miscarriage.
- Breastfeeding: avoid it. There is no good research on whether it passes into breast milk. Read our guide to ashwagandha and breastfeeding.
- Trying to conceive: speak to your GP first, as ashwagandha may affect reproductive hormones.
- Thyroid conditions: women are more likely to have thyroid problems, so check before taking it.
- PCOS and hormone-sensitive conditions: ask your doctor first. Our guide to ashwagandha for PCOS looks at the research.
If you want calm and better sleep without ashwagandha, magnesium is a gentler place to start. See magnesium glycinate and ashwagandha vs magnesium.
Ashwagandha side effects for men
Many men take ashwagandha for stress, sleep, training recovery or testosterone. A 2021 systematic review concluded that ashwagandha root and root and leaf extracts had positive effects on testosterone levels in men, although the studies were small.
The side effects for men are the same as for anyone: drowsiness, stomach upset and, rarely, liver or thyroid effects. Because it can affect hormones, ask your doctor first if you have a hormone-sensitive condition such as prostate cancer, or are having fertility treatment.
For more on how stress shows up in men, and how to manage it, see our Movember guide to stress in men.
Does ashwagandha make you feel emotionally numb?
“Does ashwagandha kill emotions” has become one of the fastest-rising ashwagandha searches in the UK. Some people, mostly in online forums, describe feeling flat, detached or emotionally numb while taking it.
Here is what we know honestly:
- Emotional blunting has not been reported as a side effect in clinical trials, which mostly looked at stress, sleep and anxiety scores.
- There is no proven mechanism. One plausible explanation is that by taking the edge off stress, some people feel less of everything, which can feel like numbness.
- People react differently to supplements, so personal reports still matter.
What to do: if you feel flat, low or detached, stop taking it and see whether you feel like yourself again within a week or two. If low mood carries on, talk to your GP.
Who should avoid ashwagandha?
- people who are pregnant, breastfeeding or trying to conceive
- anyone with a thyroid condition
- anyone with liver disease
- people with autoimmune conditions
- anyone due to have surgery (stop at least two weeks before)
- children and teenagers under 18
- people taking any of the medicines listed below
Medicine and supplement interactions
Ashwagandha may interact with:
- Thyroid medicine, such as levothyroxine
- Diabetes medicines, as it may lower blood sugar
- Blood pressure medicines, as it may lower blood pressure
- Sedatives and sleeping tablets, including benzodiazepines
- Immunosuppressants
- Anti-seizure medicines
Be careful stacking it with other sedating supplements, such as high doses of valerian or melatonin. If you take any regular medication, speak to your pharmacist before starting ashwagandha.
Is ashwagandha safe and legal in the UK?
Ashwagandha is currently legal to sell as a food supplement in the UK. In 2024 the Food Standards Agency asked for evidence on its safety, citing concerns about the thyroid, blood sugar and the liver, and the UK’s Committee on Toxicity is reviewing it. No decision has been published yet.
Elsewhere in Europe, Denmark banned ashwagandha in foods and supplements in 2023, saying a safe intake could not be established. That decision has been criticised by some researchers, and most countries still allow it.
We follow the FSA’s review closely and will update this page when it reports. Our guide to ashwagandha in the UK covers the regulation in more detail.
How to use ashwagandha more safely
- Start low. Begin with the lowest suggested dose on the label.
- Be consistent, not aggressive. More is not better.
- Avoid stacking sedatives. Don’t combine it with several other sleep aids at once.
- Take breaks. Many people take it for up to eight to twelve weeks, then pause.
- Choose a tested product from a brand that publishes lab reports.
- Stop if something feels wrong, and see a doctor for any signs of liver problems.
Ashwagandha in Evopure products
Our Flow CBD Oil contains ashwagandha root extract alongside broad spectrum CBD and maca. As with any ashwagandha product, don’t take it if you are pregnant, breastfeeding, under 18, or have a thyroid, liver or autoimmune condition, and check with your pharmacist if you take regular medication. You can read more about combining the two in CBD and ashwagandha.
If ashwagandha isn’t right for you, our Magnesium Glycinate Sleep Complex and Sleep CBD Oil contain no ashwagandha.
FAQs
Is ashwagandha safe for daily use?
Most healthy adults tolerate it well for several weeks at a time. Many people take breaks after eight to twelve weeks. Avoid it if you are pregnant, breastfeeding, or have a thyroid, liver or autoimmune condition.
Does ashwagandha kill your emotions?
Some people report feeling flat or emotionally numb, mostly online, but this has not been reported in clinical trials. If you feel flat or detached, stop taking it, and speak to your GP if low mood continues.
What are the side effects of ashwagandha for women?
The common side effects are the same for everyone: drowsiness, stomach upset and loose stools. Women should avoid it in pregnancy and while breastfeeding, and check with a GP first if they have a thyroid condition, PCOS (now also called PMOS) or are trying to conceive.
What are the side effects of ashwagandha for men?
Men report the same mild side effects as anyone. Because ashwagandha can affect testosterone and other hormones, men with hormone-sensitive conditions or having fertility treatment should ask a doctor first.
Can ashwagandha cause anxiety?
It is usually taken to ease stress, but a small number of people feel restless or more anxious. If that happens, stop taking it.
Does ashwagandha affect hormones?
Yes, it can affect thyroid hormones and testosterone. That is why people with thyroid conditions, hormone-sensitive conditions or who are pregnant should avoid it or check with a doctor first.
Is ashwagandha banned in the UK?
No. It is legal to sell as a food supplement in the UK, although the Food Standards Agency is reviewing its safety. Denmark banned it in 2023.
Is magnesium a safer alternative to ashwagandha?
Magnesium is gentler and has fewer cautions, which makes it a good first step for calm and sleep. It works differently, though, so it is not a direct replacement.
Sources
- NIH National Center for Complementary and Integrative Health. Ashwagandha.
- Björnsson HK et al (2020). Ashwagandha-induced liver injury: a case series from Iceland and the US Drug-Induced Liver Injury Network. Liver International.
- Philips CA et al (2023). Ashwagandha-induced liver injury: a case series from India and literature review. Hepatology Communications.
- Smith SJ et al (2021). Examining the effects of herbs on testosterone concentrations in men: a systematic review. Advances in Nutrition.
- Nutrition Insight (2024). UK FSA opens call for ashwagandha safety data.
This guide is general information, not medical advice.
