Who should not take ashwagandha? Side effects, interactions and warning signs
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Ashwagandha is sold as a gentle herb for stress. For most healthy adults who take it for a few weeks, the trials report mild side effects or none. That is not the same as being suitable for everyone. Several groups are advised to avoid it, and there are rare reports of liver injury.
This article lists who should not take ashwagandha, which medications it may interact with, and the symptoms that mean you should stop. It is general information for adults. Your doctor or pharmacist knows your situation and should have the last word.
The short list
| Group | Advice | Why |
|---|---|---|
| Pregnant | Avoid | The NIH advises against use in pregnancy |
| Breastfeeding | Do not use | Safety has not been established |
| Thyroid conditions or thyroid medication | Avoid unless your doctor agrees | May change thyroid hormone levels |
| Autoimmune conditions | Avoid unless your doctor agrees | May affect immune activity |
| Surgery planned | Stop beforehand, as your surgical team advises | Possible sedation and effects on blood sugar and blood pressure |
| Hormone-sensitive prostate cancer | Avoid | May raise testosterone |
| Liver disease | Avoid unless your doctor agrees | Rare cases of liver injury have been reported |
| Under 18 | Not for children or teenagers | The trials were in adults |
Pregnancy and breastfeeding
The National Institutes of Health advises that ashwagandha should be avoided during pregnancy and should not be used while breastfeeding. The trials that support its use for stress excluded pregnant and breastfeeding women, so there is no safety data to rely on.
If you are trying to conceive, treat it the same way and stop. If you have been taking it and find you are pregnant, stop and mention it at your next appointment.
Thyroid conditions
Ashwagandha may raise thyroid hormone levels. For someone with an overactive thyroid, that is the wrong direction. For someone taking levothyroxine for an underactive thyroid, it can shift a dose that was carefully adjusted, and it can make blood test results harder to interpret.
The NIH advises people with thyroid disorders, and people taking thyroid hormone medication, not to use ashwagandha without medical advice. Taking the two at different times of day does not remove the concern, because the issue is the hormone level and not absorption.
Autoimmune conditions
Ashwagandha may increase the activity of the immune system. People with conditions such as rheumatoid arthritis, lupus, multiple sclerosis or Hashimoto’s disease are generally advised to avoid it. The same applies to anyone taking medication that suppresses the immune system, including after a transplant.
Before surgery
Ashwagandha can cause drowsiness and may lower blood sugar and blood pressure. These can matter under anesthesia. Tell your surgical team about every supplement you take. A common instruction is to stop herbal supplements two weeks before a planned operation, but follow what your own team says.
Hormone-sensitive prostate cancer
Some trials reported higher testosterone in men taking ashwagandha. In a 2015 strength training trial, testosterone rose more in the ashwagandha group than in the placebo group. In a 2019 stress trial, testosterone rose in men over the study, although the difference from placebo was not statistically significant.
For that reason the NIH says ashwagandha may not be suitable for men with hormone-sensitive prostate cancer. Anyone with a hormone-sensitive condition, or taking hormone treatment, should ask their doctor first.
Liver concerns
A 2020 case series described five people with liver injury attributed to ashwagandha supplements, three in Iceland and two in the United States. Their ages ranged from 21 to 62. All developed jaundice, with symptoms such as nausea, tiredness, itching and abdominal discomfort. Symptoms began two to twelve weeks after they started the supplement.
None developed liver failure. Liver tests returned to normal within one to five months in the four patients who were followed. Laboratory analysis confirmed ashwagandha in the supplements that were available for testing and found no other toxic compounds. Four of the five were also taking other supplements.
These cases are rare against the number of people who take ashwagandha. They are the reason to avoid it if you have liver disease, and the reason to know the warning signs below.
Medication interactions
The NIH lists the following types of medication as ones ashwagandha may interact with.
| Medication type | Concern |
|---|---|
| Thyroid hormone, such as levothyroxine | May add to thyroid hormone levels |
| Diabetes medication | May lower blood sugar further |
| Blood pressure medication | May lower blood pressure further |
| Immunosuppressants | May work against the medication |
| Sedatives, including sleep medication and benzodiazepines | May add to drowsiness |
| Anticonvulsants | May add to drowsiness |
This is a list of possible interactions, not a list of proven harms. It means the combination should be checked by someone who can see your full medication list. A pharmacist can do this in a few minutes.
Alcohol is also sedating. Combining it with a supplement that causes drowsiness is best avoided.
Side effects in people who can take it
In the trials, side effects were mild and occurred at a similar rate to placebo. The 2012 stress trial described them as mild and comparable in both groups. The 2019 trial of a root and leaf extract reported no adverse events in 60 participants over 60 days. The 2020 sleep trial reported no withdrawals due to side effects among 150 participants.
The side effects the NIH lists are:
- stomach upset
- loose stools or diarrhea
- nausea or vomiting
- drowsiness
Taking it with food helps the first three. For drowsiness, move the dose to the evening. See ashwagandha in the morning or at night.
Keep the scale of the evidence in mind. A 2022 meta-analysis found 12 trials with about 1,000 participants in total. That is enough to see common side effects. It is not enough to detect rare ones, which is how the liver cases came to light only through case reports.
Warning signs: stop and see a doctor
- Yellowing of the skin or the whites of the eyes
- Dark urine or pale stools
- Itching that does not go away
- Nausea, loss of appetite or abdominal pain without another cause
- A racing heart, tremor, unexplained weight loss or feeling unusually hot
- A rash, swelling or difficulty breathing. Treat the last as an emergency
Take the bottle with you. The label tells the doctor which extract and how much.
How long is too long?
The NIH says ashwagandha appears to be safe for up to about three months and that its long-term safety is unknown. The trials ran for six to ten weeks. Nobody has studied what a year of daily use does.
A cautious approach is to review at eight to twelve weeks. If it has not helped, stop. If it has, ask your doctor whether to continue or to take a break.
A note on gummies
A gummy does not change who should avoid ashwagandha. It adds two things to check.
- Sugar. Most gummies contain added sugar. Goli Ashwagandha Gummies list 2 g of sugars per gummy, which is 8 g at the suggested four gummies a day. This matters if you manage your blood sugar. See added sugar in gummies.
- Other ingredients. The same product lists vitamin D at 12.5 mcg per gummy, or 50 mcg at four gummies. Add that to any other vitamin D you take. The upper limit for adults is 100 mcg a day. See can you take too many gummy vitamins.
Gummies look and taste like sweets. Keep them out of the reach of children. Ashwagandha gummies are for adults only.
Our Goli Ashwagandha Gummies review lists who the product is not for. The ashwagandha ingredient guide covers the research.
If ashwagandha is not for you
Stress has no supplement shortcut. The approaches with the best evidence are regular physical activity, enough sleep and, where stress is persistent, talking therapy. If stress or anxiety is affecting your work, sleep or relationships, see a doctor before trying any supplement.
Among supplements, L-theanine has a different safety profile and a smaller body of evidence. It has its own cautions, so check those too. Other options are on the stress gummies page.
The short version
- Avoid ashwagandha if you are pregnant or breastfeeding.
- Get medical advice first if you have a thyroid, autoimmune or liver condition, or hormone-sensitive prostate cancer.
- Check interactions with thyroid, diabetes, blood pressure, immune, seizure and sedative medication.
- Stop before surgery as your team advises.
- Common side effects are mild: stomach upset and drowsiness.
- Jaundice, dark urine or persistent itching mean stop and see a doctor.
- Safety is studied to about three months only.
Common questions
Who should not take ashwagandha?
People who are pregnant or breastfeeding, and people with thyroid or autoimmune conditions, liver disease or hormone-sensitive prostate cancer, unless a doctor agrees. It is also not for anyone under 18.
Can I take ashwagandha with thyroid medication?
Not without your doctor’s agreement. Ashwagandha may raise thyroid hormone levels and change how much medication you need.
Can ashwagandha damage the liver?
Rare cases of liver injury have been reported, with jaundice starting two to twelve weeks after people began taking it. The cases in the main published series resolved after stopping.
Is ashwagandha safe in pregnancy?
No. The NIH advises avoiding it during pregnancy and not using it while breastfeeding.
Can I take ashwagandha with antidepressants or anxiety medication?
Ask your doctor or pharmacist. Ashwagandha can add to the drowsiness caused by sedating medication, and the combination has not been well studied.
What are the most common side effects?
Stomach upset, loose stools, nausea and drowsiness. In trials they were mild and about as frequent as with placebo.
Sources
- NIH National Center for Complementary and Integrative Health. Ashwagandha: usefulness and safety.
- NIH Office of Dietary Supplements. Ashwagandha: is it helpful for stress, anxiety, or sleep? Fact sheet for health professionals.
- Björnsson HK, et al. Ashwagandha-induced liver injury: a case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020.
- Wankhede S, et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. 2015.
- Lopresti AL, et al. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2019.
- Chandrasekhar K, et al. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian J Psychol Med. 2012.
- Deshpande A, et al. A randomized, double blind, placebo controlled study to evaluate the effects of ashwagandha (Withania somnifera) extract on sleep quality in healthy adults. Sleep Med. 2020.
- Akhgarjand C, et al. Does ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials. Phytother Res. 2022.
These statements have not been evaluated by the Food and Drug Administration. Products discussed here are not intended to diagnose, treat, cure or prevent any disease. This page is not medical advice. It is written for adults 18 and over.