Ashwagandha: What the Evidence Says and Who Should Avoid It
Medically Reviewed by Dr. Pedro Yelamo Vera, MD
Licensed Physician No. 484814280 · Official Medical College of Bizkaia (Spain)Last reviewed: 5 November 2026
Ashwagandha is sold in Spain as a supplement for stress and sleep.
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Ashwagandha (Withania somnifera) is a herb from Indian Ayurvedic medicine. In Spain it is sold as a food supplement for stress, anxiety and sleep. Small trials suggest a modest effect on stress. But rare cases of liver damage have been reported, and it should not be taken in pregnancy. This guide is by Dr. Pedro Yelamo Vera, a GP licensed in Spain (Colegiado No. 484814280).
- Ashwagandha is a food supplement, not a medicine. It did not have to prove it works before going on sale.
- Small, short studies suggest it may ease stress a little and help sleep a little. The evidence is weak.
- Rare cases of liver damage have been reported, some serious. Stop it if your skin or eyes turn yellow or your urine goes dark.
- It can affect the thyroid and add to sedatives, diabetes medicines and blood pressure medicines.
- It is not advised in pregnancy or when breastfeeding. Denmark banned its sale in 2023.
- It does not replace treatment for anxiety. If anxiety holds you back, see a doctor.
What is ashwagandha?
It is a shrub from India and North Africa. The root is the part most used, as a powder or an extract. It is also called Indian ginseng or winter cherry, though it is not a ginseng. It is sold as an "adaptogen". That is a marketing word, not a medical one.
In Spain you find it in pharmacies, health shops (herbolarios), supermarkets and online as a complemento alimenticio (food supplement). A supplement does not go through the checks that the Spanish medicines agency (AEMPS) needs for a medicine. The amount of herb, the part of the plant and the purity vary from brand to brand.
What is ashwagandha good for?
It has no approved medical use. It is sold for stress, anxiety, sleep, energy, sport, sex drive and women's health. The US National Institutes of Health (NIH) say there is not enough proof for most of these uses.
Does ashwagandha work for anxiety and stress?
It may help a little with stress, but the proof is weak. Several small, short trials, mostly in India, found less stress and slightly lower cortisol than with a dummy pill. They lasted only a few weeks. Many were paid for by the firm that makes the extract.
An anxiety disorder is a different matter. It has treatments that are proven to work, such as talking therapy (CBT) and some medicines. If anxiety keeps you awake, makes you avoid places or affects your work, see a doctor before you try a supplement.
Does it help you sleep?
A review of five small studies found a small gain in sleep. The gain was a bit larger in people with insomnia. That is not much data. For long-term insomnia, the first choice is a type of talking therapy called CBT for insomnia.
What about ashwagandha and women's health?
Very little is known. It is sold for the menopause, fertility, sex drive and polycystic ovaries (PCOS). But there are very few studies, with few women, over a short time. None of them is enough to recommend it for these uses.
The bigger worry is safety for women who could get pregnant:
- Pregnancy: some experts say to avoid it because of reports of possible miscarriage. Denmark banned its sale in 2023 over doubts about safety in pregnancy. France's food safety agency (ANSES) advised against it in pregnancy in 2024.
- Breastfeeding: there is no safety data. The NIH advise not to take it.
- Trying for a baby: talk to your doctor before you take any supplement.
Why can it harm the liver?
No one knows exactly why, but there are published cases of liver damage. LiverTox, the NIH database on liver harm from drugs and herbs, rates it as a likely cause. It tends to start between one week and a few months after the first dose. Most people get better when they stop. Some cases have been serious. In Australia, deaths and one liver transplant have been reported.
Stop it and see a doctor if you notice:
- yellow skin or eyes;
- dark urine or pale poo;
- itching all over;
- feeling sick, deep tiredness, or pain in the upper right side of your tummy.
If it has caused a liver problem before, do not take it again.
Does it affect the thyroid?
Yes, it can. Some studies show it raises thyroid hormones. There are cases of an overactive thyroid that settled once people stopped it. If you have a thyroid problem or take levothyroxine, such as Eutirox, ask a doctor first.
Who should not take ashwagandha?
- Women who are pregnant or breastfeeding.
- Children and teenagers.
- People with liver disease, or who had liver damage from a supplement.
- People with thyroid disease.
- People with an autoimmune disease, such as lupus or rheumatoid arthritis.
- Anyone with an operation booked.
- Men with hormone-sensitive prostate cancer.
Ask first if you take sedatives, sleeping tablets, diabetes or blood pressure medicines, epilepsy medicines, thyroid hormone or medicines that dampen the immune system.
How much ashwagandha should I take?
This guide does not give supplement doses. If you choose to take it, do not go over what the pack says. Do not mix products that contain it. Ask your pharmacist or doctor, above all if you take other medicines. Its long-term safety is not known.
In English: what is the equivalent?
The name is the same everywhere: ashwagandha. In Spain, labels may also say ginseng indio or bufera. In the UK and the US it is also sold as a food supplement, not a licensed medicine. There is no prescription version in any of the three countries.
When to see a doctor
- Stress or anxiety affects your daily life, work or sleep.
- You get palpitations, shaking or weight loss while taking it.
- You notice signs of liver damage.
- You took it while pregnant or breastfeeding.
When to call 112
- Confusion, deep drowsiness or vomiting blood with yellow skin.
- Swelling of the face, lips or tongue, or trouble breathing.
- Chest pain or a racing heartbeat.
If you have thoughts of suicide, call 024, Spain's free suicide prevention line, or 112 if you are in danger now.
Frequently asked questions about ashwagandha
Do you need a prescription for ashwagandha in Spain?
No. It is sold as a food supplement, with no prescription. That does not mean it is harmless.
Is ashwagandha banned in Spain?
No. It is sold as a food supplement. Denmark banned it in 2023, and other European countries have issued warnings.
Can I take ashwagandha with antidepressants?
Ask first. It may add to the drowsiness of other medicines that act on the brain, and it has not been well tested with them.
Does ashwagandha cause weight gain?
There is no good proof that it does. A few small studies mention weight changes, but the data are not reliable.
Can anxiety be assessed by video?
Yes. A doctor can assess your symptoms by video, check what you take and suggest a plan. A prescription is never guaranteed.
Getting a medical assessment
If you have stress or anxiety and want a doctor's advice, you can book a video consultation with Dr. Pedro Yelamo Vera, a physician registered in Spain. You can also read about anxiety treatment, how to lower cortisol and insomnia. A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.
This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.
Sources
This content is written and reviewed by a licensed physician with reference to the following sources.
