Health experts have warned about the dangers of buying versions of the weight loss drugs Wegovy and Ozempic from online pharmacies.

Amid shortages of the drugs due to a surge in popularity, pharmacies were given the green light to mix their own versions using semaglutide, the active ingredient in Wegovy and Ozempic, in a process referred to as compounding.

However, it has led to the Food and Drug Administration (FDA) in America issuing a warning about the increase of black market versions and have also advised that the compounded drugs should not be taken if the approved drug is available.

The FDA said there have been reports of side effects relating to the compounded drugs but did not reveal what these are.

Semaglutide’s side effects are known to include diarrhoea, nausea and constipation.

The FDA said: “Patients should be aware that some products sold as ‘semaglutide’ may not contain the same active ingredient as FDA-approved semaglutide products.

“Products containing these salts, such as semaglutide sodium and semaglutide acetate, have not been shown to be safe and effective.

“Purchasing medicine online from unregulated, unlicensed sources can expose patients to potentially unsafe products that have not undergone appropriate evaluation or approval, or do not meet quality standards.”

Semaglutide helps people lose weight by simulating how a hormone in the body works and making them feel full.

Both Wegovy and Ozempic are approved for people with type 2 diabetes but only Wegovy is used to combat weight loss in people with obesity.

There was a 21-fold increase in prescriptions of the two drugs, and Eli Lilly’s Mounjaro, between 2019 and 2022, with more than five million prescriptions handed out last year.

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