Ashwagandha is considered safe at the doses usually recommended, and for people in good health. However, some serious side effects have been reported. Even if they are rare, it is important to be aware of them before taking an ashwagandha food supplement.
The dangers of ashwagandha for the liver
In recent years, several cases of liver damage have been reported in the scientific literature after taking ashwagandha in excessively high doses [2],[3]. Patients generally develop jaundice and symptoms, such as nausea, lethargy, itching and abdominal discomfort. Researchers believe that a compound present in ashwagandha extracts is responsible. The compound in question is a withanolide: withanone, which is present in significant quantities in ashwagandha, and to which many of its medicinal properties are attributed. But withanone has chemical groups in its structure - known as toxicophores - which, in medicines, are associated with undesirable effects and toxicity. Fortunately, we have a cellular detoxification system - gluthation - which neutralises these toxicophores, making the drugs containing them safe if used correctly. The same applies to ashwagandha. If taken in recommended doses, despite the presence of withanone toxicophores, our cellular detoxification system makes it safe. However, if taken in high doses, gluthation is no longer able to cope and detoxify the groups responsible for withanone toxicity, which can lead to liver damage[4]. In the majority of cases, liver damage regresses within a few months of stopping ashwagandha and with appropriate treatment.
Effects of ashwagandha on the thyroid gland
Several cases of hyperthyroidism (thyrotoxicosis) caused by high-dose ashwagandha supplementation have been reported in scientific studies, even in people who initially had no thyroid problems[6]. After two months of ashwagandha supplementation at a dose of 1950 mg per day (which is much higher than the recommended dosage), one woman experienced a worsening of her anxiety symptoms, as well as other symptoms, such as extreme fatigue, weight loss and an increased resting heart rate[7]. Hyperthyroidism was confirmed, and stopping ashwagandha allowed her to return to normal.
However, in the majority of cases, scientific studies report a beneficial effect of ashwagandha on hypothyroidism[8],[9]. As a reminder, hypothyroidism is characterised by insufficient production of the thyroid hormones T3 and T4. It appears that ashwagandha's stimulant properties may encourage the thyroid gland to produce these hormones. Ashwagandha could, therefore, help maintain normal thyroid function and offer support to people suffering from hypothyroidism.
However, few clinical studies have been carried out on this subject, which underlines the importance of caution:
A clinical study was carried out by GANNON in 2014 on 60 patients and confirmed the pharmacological results in animals, particularly with regard to T4 secretion, suggesting therapeutic potential in hypothyroidism.
A more recent study conducted by SHARMA in 2018 also revealed promising results. In this placebo-controlled clinical study, 55 subjects with hypothyroidism were given 600 mg of ashwagandha extract for 8 weeks. The results showed a significant decrease in TSH after 4 and 8 weeks of treatment, as well as a significant increase in T4 and T3 levels. These results suggest the potential of ashwagandha in normalising hormone levels in people with hypothyroidism.
However, it is important to stress that ashwagandha should not replace prescribed medication for hypothyroidism. Before starting any ashwagandha supplementation, it is advisable to consult a healthcare professional to assess the potential dangers and benefits, particularly for people with thyroid problems.
