10 Ashwagandha Side Effects & Contraindications to Know About

Published on January 13, 2023

By Kristen Boye BS, Natural Health

Kristen Boye

Kristen Boye is a natural health expert, writer, copywriter, and editor. Kristen was raised on an organic farm in British Columbia which inspired her life’s work. She holds a Bachelor’s Degree in Natural Health, is a Certified Natural Foods Chef, co-owner of a medicinal herb farm, and is a natural foods and children’s health advocate. Kristen lives with her husband and two children on their medicinal herb farm in Western North Carolina.

Ashwagandha is one of the most revered herbs in Ayurveda, the traditional wellness practice of India.

It’s also surging in popularity in the Western world due to its potential benefits for various health concerns. 

Ashwagandha as a whole herb/root extract is very safe, with a long track record of success and very few adverse events reported.REF#258REF#259REF#260

However, you should be aware of some rare but possible side effects and contraindications before taking Ashwagandha

This information is especially important if: 

  • You’re taking high doses of a pure alkaloid Ashwagandha extract
  • You’re taking certain medications
  • You have food allergies
  • You’re pregnant or nursing 
  • Or have certain types of chronic illness

In this article, we share ten potential Ashwagandha side effects you should know about, plus the benefits of the herb, and how to choose a safe and high-quality supplement.

What Is Ashwagandha?

Ashwagandha, also known as Ashwagandha Root, Indian Ginseng, Winter Cherry, or Withania somnifera, is an herb belonging to the nightshade family.

Ashwagandha is native to Eastern Asia and has been used extensively in Ayurveda for thousands of years. 

It’s been traditionally used to support a variety of concerns, including REF#261

In herbalism, Ashwagandha is considered a nervine, which supports the nervous system, and an adaptogen, which helps the body adapt to physical, mental, and emotional stress.*

Modern research on Ashwagandha has identified over 50 chemical constituents, including steroidal alkaloids and lactones, collectively known as withanolidesREF#262, which are involved in the plant’s actions and potential health benefits.

Now that you have a basic understanding of this incredible plant, let’s look at some potential side effects of Ashwagandha.

Potential Side Effects of Ashwagandha

Before we get into the potential side effects of Ashwagandha, it’s important to understand a few key points:

  • Side effects from Ashwagandha have been proven to be rare.REF#258REF#259REF#260
  • Ashwagandha has an extensive history of safe usage going back thousands of years.
  • There have been no reports of serum enzyme elevations (a marker of distress) occurring during Ashwagandha therapy and no mention of serious adverse events or hepatotoxicity in clinical trials.REF#259
  • Based on clinical trials, we don’t know how Ashwagandha root extract affects the body when taken long-term (longer than eight months).REF#260
  • Although a few adverse events have been reported from taking Ashwagandha-containing supplements, it was unclear if the Ashwagandha, or another ingredient or contaminant, caused the reaction.REF#263
  • Most adverse events reported from Ashwagandha have occurred in high doses of purified or isolated versions of the herb, such as those with high alkaloid content, vs. the whole herb.REF#259
  • Water extracts of Ashwagandha, however, did not create any toxicity, even at levels as high as 2000 mg/kg – which is about 50 times the recommended dosage for humans.REF#259

That said, there are still some potential side effects and contraindications to know about before taking Ashwagandha.

1: Ashwagandha Can Cause Reactions In Those With Nightshade Allergies or Sensitivities

As stated in the introduction, Ashwagandha belongs to the nightshade or Solanaceae family of plants.REF#264 Other common nightshades include potatoes, tomatoes, peppers, and eggplant.

Nightshades can cause an allergic reaction or sensitivity in some people.

Therefore, if you have a history of allergies or sensitivity to nightshades, Ashwagandha could produce an allergic reaction or other unpleasant side effects.

If you have a nightshade allergy or sensitivity and are looking for an Ashwagandha alternative, check out: Beyond Ashwagandha: 5 Calming Herbs for Stress Support.

#2: Ashwagandha May Aggravate Certain Thyroid Conditions

On the flip side, Ashwagandha has also been shown to support thyroid hormone production.*REF#265 

The takeaway: if you have or suspect a thyroid issue, talk to your doctor or healthcare practitioner before taking Ashwagandha.

If your doctor or healthcare practitioner recommends Ashwagandha for thyroid and metabolic support, consider Gaia Herbs Thyroid Support.*

#3: Ashwagandha May Not Be Appropriate For Pregnant Or Nursing Mothers

There is very little evidence on the safety of Ashwagandha during pregnancy and nursing.

Therefore, most experts recommend refraining from taking Ashwagandha during these times.

Similar online articles written on this topic report there is evidence Ashwagandha may cause contractions or miscarriage during pregnancy. 

Upon extensive investigation, we could not find any scientific evidence to back up these claims.

Many of these sites reference Memorial Sloan Kettering Cancer Center’s article on Ashwagandha warning of these effects. 

However, we could not find corresponding evidence within their references to support this statement about Ashwagandha specifically (although other herbs can have this effect, which may have led to their recommendation to avoid it during pregnancy).

Ultimately, the lack of safety data suggests it’s best to avoid Ashwagandha if you’re nursing or pregnant.

#4: Large Doses of Ashwagandha May Cause Stomach Upset In Some People

One study titled: “Adjunctive Use of a Standardized Extract of Withania somnifera (Ashwagandha) to Treat Symptom Exacerbation in Schizophrenia: A Randomized, Double-Blind, Placebo-Controlled Study,” showed that participants taking Ashwagandha reported mild to moderate drowsiness, lower abdominal discomfort, and loose stools.REF#267

However, even with those adverse events, researchers concluded their findings suggest Ashwagandha provided “significant benefits, with minimal side effects, for negative, general, and total symptoms and stress in patients with recent exacerbation of schizophrenia.”

Large doses of purified extract of Ashwagandha compounds, such as alkaloids, may also cause this effect.

#5: Ashwagandha May Potentially Interact With Certain Drugs

There have not been extensive drug-interaction studies with Ashwagandha. 

However, medical experts generally agree Ashwagandha may be contraindicated with certain prescription drugs.

However, its contraindication level is considered mild to moderate.REF#268REF#269

Meaning it may not cause problems for people taking medication. If it does, they will likely be mild to moderate.

Here’s a list of potential medications contraindications when taking Ashwagandha:

  • Sedatives
  • Immunosuppressants
  • Some thyroid medications
  • Anticonvulsants
  • Anti-diabetic drugs
  • Anti-hypertensive drugs

Your doctor can tell you if Ashwagandha is safe and compatible with the drugs you’re taking.

For example, some integrative functional medicine physicians will monitor a patient’s thyroid hormone levels while taking Ashwagandha and adjust their medication dosage as needed. 

However, that may be contraindicated for others based on individual health factors and their doctor’s recommendations.

Regardless, always talk to your doctor before taking Ashwagandha if you’re on medication.

#6: Ashwagandha May Cause Drowsiness

Ashwagandha is widely used and has been shown to support a healthy sleep cycle.*REF#270

Drowsiness may be a welcomed side effect if falling asleep is your goal!

However, if you’re new to taking Ashwagandha, use caution when taking it until you know how it affects you.

It’s also advisable to check with your doctor if you’re taking other sleep-promoting supplements or medication.

That’s not to say you can’t take it during the day or that it may not benefit some people.*

In many studies evaluating its potential health benefits, Ashwagandha was administered at various times of day with no reports of excessive drowsiness.*

It may be beneficial for some people to take it in the morning and/or before bed due to its supportive effects on the cortisol awakening response (your body’s ability to wake up feeling refreshed and energized in the morning).REF#271

Bottom line: Begin taking Ashwagandha before bed first and see how it affects you. Then, try taking a dose during the day while you’re at home (not operating machinery or driving) and see how it affects you.

We also recommend checking with your healthcare practitioner for individual recommendations.

If you’re interested in trying Ashwagandha before bed to support sleep, check out Gaia Herbs SleepThru® formula with Ashwagandha, Passionflower, and Jujube Date.*

#7: Rare Cases of Liver Problems Have Been Reported

Per information published in LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, there have been rare reports of liver damage in people taking high doses of Ashwagandha-containing supplements.REF#263

However, this point is controversial for three reasons.

#1: The published information notes, “In clinical trials, there have been no reports of serum enzyme elevations occurring during therapy and no mention of serious adverse events or hepatotoxicity [from taking Ashwagandha].”

#2: Adverse events were reported in people taking supplements “containing Ashwagandha.” So it’s unclear whether the Ashwagandha caused the toxicity or another ingredient. 

As is indicated in this quote from the researchers: 

“Because commercial herbal preparations are often mixtures of herbs and nutritional products and can be mislabeled and contain unknown herbs and medications, it is not always clear whether the reported cases were due to Ashwagandha and one of its components or to a contaminant. ”

This brings us to the third point of controversy: 

#3: Not all Ashwagandha is created equal. 

Sadly, as noted in the quote, many sources of herbs are tainted with various toxins that could injure the liver, including heavy metals, pesticides, mold, mildew, and even drug residues.

That’s why purchasing herbal supplements from companies that follow cGMP manufacturing guidelines, use organically-produced herbs, and do third-party testing for herbs’ identity and various contaminants like those listed above is essential.

Learn more about the quality and sourcing of herbs here.

8: Ashwagandha May Activate The Immune System

Ashwagandha has demonstrated potential immune-modulating effects.REF#272

For generally healthy people, this is a potential benefit.

However, for those with certain autoimmune conditions, Ashwagandha could cause unwanted side effects related to the immune system.

Always check with your doctor before taking Ashwagandha if you have an autoimmune disorder.

9: Ashwagandha May Not Be Appropriate Before Surgery

Some medical professionals believe Ashwagandha’s effects on the nervous system could interfere with medications used during surgery.

Talk to your doctor about when to stop taking Ashwagandha before surgery.

10. Ashwagandha May Affect Testosterone Levels

As discussed in 8 Surprising Ways Ashwagandha Benefits Men, the herb’s testosterone support may benefit some people.REF#273* 

However, if you’re suffering from prostate issues or hormonal imbalances, check with your doctor first.

Other Extremely Rare, Temporary, and Mild Side Effects Of Ashwagandha

Per evidence published in the Journal Ethnopharmacology titled: “Safety and clinical effectiveness of Withania Somnifera (Linn.) Dunal root in human ailments'' there have been other rare and mild side effects reported.REF#260

These rare, mild, and mainly temporary type side effects include:

  • Giddiness
  • Hallucinations
  • Vertigo
  • Nasal congestion (rhinitis)
  • Cough
  • Cold
  • Decreased appetite
  • Nausea
  • Constipation
  • Dry mouth
  • Hyperactivity
  • Nocturnal cramps
  • Blurring of vision
  • Hyperacidity
  • Skin rash
  • Weight gain

Keep in mind, there is no way to know whether these rare side effects were related to the Ashwagandha or something else. 

Is Ashwagandha Safe?

As previously outlined, Ashwagandha is considered very safe for most people to take based on the very low incidents of reported side effects in studies and its long history of use.

Even regarding potential drug interactions, there isn’t any evidence of serious interactions.REF#268REF#269

However, if you have any health issues listed above or are on medication, always check with your doctor before taking Ashwagandha.

Now let’s talk about quality.

We said it before, but quality is essential when choosing an Ashwagandha supplement—or any type of supplement.

To recap, when choosing a safe Ashwagandha supplement, insist on:

  • Certified organic Ashwagandha
  • Third-party testing for identity, potency, and contaminants
  • Avoid high-doses of purified Ashwagandha constituents, such as alkaloids—the whole herb or whole herb extracts are always safer 
  • Ashwagandha that’s free from fillers, binders, or excipients
  • Products made in a cGMP facility

By being proactive in your awareness of potential Ashwagandha side effects and contraindications, communicating with your doctor and healthcare providers, and following this quality criterion, you’re in a position to choose the safest herbs for you and your healthy lifestyle.

To learn more about the benefits of Ashwagandha, check out the following articles:

If these side effects and contraindications do not apply to you and you’re interested in trying Ashwagandha, check out Gaia Herbs Organic Ashwagandha Supplement collection.


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