Pharmacists have warned people not to buy fake weight loss drugs online, as a shortage of Ozempic is expected to continue until next year.

The National Pharmacy Association (NPA) suggested this could result in “an explosion in the unlicensed sale of prescription drugs online”.

Weight loss injections have been popularised by celebrity endorsements and before-and-after pictures online, but fake versions can be dangerous.

Ozempic is a brand of semaglutide that helps people with type 2 diabetes control their blood sugar levels, but in some countries it is also increasingly prescribed for weight loss.

There is currently a shortage of Ozempic, as demand is high and some doctors are prescribing it without a prescription, as it is not licensed for weight loss.

Although Ozempic, available on the NHS, helps people with type 2 diabetes, people are also using it to lose weight due to its ability to suppress appetite.

This has led to a shortage of the medicine and also a rise in the sale of counterfeit vaccines.

Wegovy, another brand of semaglutide, is licensed for weight management and is also available on the NHS.

The NPA, which represents 5,000 independent community pharmacies across the UK, is urging people to speak to a pharmacist or GP rather than buying medicines online from sellers who are not registered or regulated in the UK.

It also warned that shortages of Ozempic, manufactured by pharmaceutical company Novo Nordisk, were likely to continue into next year.

NPA president Nick Kay said: “Pharmacists are extremely concerned that the current medicine shortage crisis could lead to a huge increase in the unlicensed sale of medicines online.

“Stocks of Ozempic in community pharmacies across the UK have become very low and it is important that it is prioritised for those with the greatest clinical need.

“Given the precarious supply situation of this and other vital medicines, the risk of people ordering supplies from disreputable online sellers is very high.”

Last year the Medicines and Healthcare products Regulatory Agency (MHRA) reported that a small number of people had been hospitalised with symptoms including hypoglycaemic shock and coma after using potentially counterfeit pens.

In January, the Department of Health and Social Care told healthcare providers not to prescribe the weight loss drug off-label, and said existing stocks should be reserved for patients with type 2 diabetes.

It said supply issues have arisen due to increased demand and off-label use.

“We don’t know how prevalent off-label prescribing is, but we know (it happens),” Mr. Kaye said.

He suggested people could check whether an online provider is registered with the General Pharmaceutical Council or the Pharmaceutical Society of Northern Ireland.

A Department of Health and Social Care spokesperson said: “We strongly advise the public not to buy regulated medicines from unauthorised online retailers or beauty salons as they may be dangerous.”

It said the MHRA would continue to take action against those who illegally traffic drugs, and said the Government was trying to shift the focus from treatment to prevention in tackling the obesity problem.