Ashwagandha Side Effects: What You Need To Know

Ashwagandha side effects

Ashwagandha side effects are very rare, are associated with high doses, and often occur in products containing additional ingredients.

What Is Ashwagandha?

Ashwagandha is an increasingly popular Ayurvedic herb that is derived from extracts of the roots of the shrub’ Withania somnifera’, a low growing evergreen shrub that is found in India and Southeast Asia. 

As discussed in my article ‘Ashwagandha Benefits: Learn Why It’s My Favourite Health Supplement,’ it is reported to have neuroprotective and anti-inflammatory activities and is used to treat stress, fatigue, and pain, among other conditions. There has been a huge amount of scientific research over the last few years into Ashwagandha and its health benefits, and let’s not forget it has been used in Ayurvedic medicine for centuries. (source)

Before discussing the potential Ashwagandha side effects, I’d like to highlight a few important points:

  • Ashwagandha side effects are rare, based on both the published research and a very long history of use – so it is generally very safe to use.
  • There have been zero reports of elevated serum enzymes (a marker of distress) in the clinical studies when participants have been taking Ashwagandha. There have also been no serious adverse events or liver toxicity reported in clinical studies. (source)
  • There is no evidence of its safety profile when taken long-term (longer than eight months). I therefore often recommend cycling on and off Ashwagandha (nothing should be needed long term anyway!)
  • When adverse events happened, the researchers couldn’t identify if it was caused by the Ashwagandha because there were other ingredients in the product.
  • Most adverse events reported from Ashwagandha have occurred in inappropriate high doses.

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

If you have a nightshade allergy or sensitivity, you may react to Ashwagandha 

Ashwagandha belongs to the nightshade family of plants, which includes potatoes, tomatoes, and peppers. Interestingly, some people have an allergy, or sensitivity, to nightshades; therefore, if you react to nightshades, you may want to be cautious about using Ashwagandha.

Ashwagandha Side Effects and the Thyroid 

Ashwagandha can aggravate thyroid function in some individuals. However, Ashwagandha has also been shown to be beneficial in those with subclinical hypothyroidism (source)

It makes sense, therefore, to speak with a health practitioner before taking Ashwagandha if you have or suspect a thyroid issue.

Ashwagandha May Not Be Appropriate If Pregnant Or Breastfeeding

There is no evidence on the safety profile of Ashwagandha during pregnancy and breastfeeding, and therefore, I recommend not taking Ashwagandha during these times.

Large Doses of Ashwagandha May Cause Stomach Upset 

In one study (source), some participants reported mild drowsiness, lower abdominal discomfort, and loose stools. These symptoms were also transient. The dose recommended in this study was 1000mg/day, so at the higher end of the common range recommended. More commonly, you’ll see 600mg recommended.

Ashwagandha May Cause Drowsiness

Anecdotally, some people find that Ashwagandha can cause drowsiness.

However, bear in mind that in many of the studies investigating the health benefits of Ashwagandha, it was administered at various times of day with no reports of excessive drowsiness. I haven’t found this to be a common side effect either.

Rare Cases of Liver Problems Have Been Reported

There have been some very rare reports of liver damage in people taking high doses of Ashwagandha-containing supplements. 

However, this is quite a controversial point, as we have already mentioned. 

  • Research has reported that there have been no reports of serum enzyme elevations during the supplementation of Ashwagandha and no mention of serious adverse events or liver toxicity.
  • In the report mentioning adverse effects, the participants took a product with multiple ingredients.
  • Some cheaper products have been shown to be contaminated with various environmental toxins.

In fact, the authors of the paper even say, “The possibility of mislabeling or adulteration with hepatotoxic herbal products is always an issue in commercial multi-ingredient dietary supplements.” (source)

Ashwagandha Modulates The Immune System

Ashwagandha has been shown to have immune-modulating effects. While this may be a positive thing in healthy individuals, in those with certain autoimmune conditions, Ashwagandha could cause side effects due to this immune system modulation.

I’d recommend speaking with your healthcare practitioner before starting Ashwagandha if you would like to try it and have an autoimmune disease. 

Ashwagandha May Affect Testosterone Levels

As discussed in my article Ashwagandha Benefits: Learn Why It’s My Favourite Health Supplement, the herb has been shown to increase testosterone, which may be beneficial for some but not for others! 

If you’re suffering from prostate issues or hormonal imbalances, I’d consider speaking with a healthcare practitioner before starting Ashwagandha.

Ashwagandha May Not Be Appropriate Before Surgery

Ashwagandha might be contraindicated with medications prescribed during surgery.

Speak with your doctor about taking ashwagandha pre/during/post a surgical procedure.

Other Extremely Rare Ashwagandha Side Effects

Per evidence published in the Journal of Ethnopharmacology (source), there have been other rare and mild side effects reported. 

These rare, mild, and mainly temporary type Ashwagandha 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

What To Do if You Have Reacted to Ashwagandha?

It’s important to speak with a primary health care practitioner, but even in the few cases of actual liver injury caused by high dose or contaminated Ashwagandha, the injury has been self-limited in course and thus without acute liver failure or persistent liver injury.

In most instances, the liver injury subsided within 1 to 3 months of discontinuing the herbal product. (source)


Alex Manos Profile 2015 AM Logo scaled

Alex is a certified Functional Medicine Practitioner (IFMCP) and has a MSc in Personalised Nutrition. He is also a breathwork facilitator with a background in personal training and massage therapy. He also runs The Resiliency Program - a 24 week program aimed at building physical, mental, emotional, and spiritual resilience.

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