Popular health supplement used by Gwyneth Paltrow, Jennifer Lopez and Meghan Markle is being investigated by food authorities over concerns it could damage the thyroid and liver

Nutrition authorities are investigating a popular dietary supplement because it may harm the thyroid and liver.

The product, ashwagandha, is an herb found in India and the Middle East and has long been used in folk medicine there.

It has become increasingly popular in the UK over the past decade, amid claims that it can reduce anxiety and improve sleep quality.

Notable candidates include Gwyneth Paltrow, Jennifer Lopez and Meghan Markle.

It is commonly sold in tablets, gummies, and water-soluble powder, which are regularly promoted by social media influencers on TikTok and Instagram.

A bottle of ashwagandha gummies. The popular health supplement is being investigated by food authorities over concerns that it could harm the liver and thyroid.

High profile users of the drug include the Duchess of Sussex, Meghan Markle

However, last month the Food Standards Agency (FSA) announced that it was gathering evidence on the safety of using ashwagandha.

According to the FSA, there are ‘no safe levels or established limits’ in the UK for the amount of ashwagandha that can be used in supplements.

The supplement was said to be associated with ‘thyroid toxicity’ and ‘possible liver toxicity’.

The FSA added that ashwagandha may also affect ‘thyroid hormone levels’ and have ‘hypoglycaemic effects’ – meaning it can lower blood sugar levels.

The FSA has called on experts and companies selling ashwaganda to provide evidence on the safety of the supplement.

Ashwagandha roots and powder. The drug has become popular due to claims that it can reduce anxiety and improve sleep quality.

London-based nutritionist Elizabeth Montgomery said: ‘As with any supplement you take, people should be careful. Ashwagandha has been used for thousands of years and has been shown to help with stress.

But if you take too much of it, it can also have a negative effect on your body and cause all kinds of complaints.

‘That’s why it’s important that we have an upper limit for what can be added to supplements.

“They need to be properly regulated because people don’t understand how they work, especially when they are combined.”