COUNTERFEIT WEIGHT-LOSS injections ordered online which contained the wrong ingredient and posed a “significant risk” to safety have been seized.

The fake injection pens were posing as the weight-loss injection Mounjaro, but instead of containing the correct ingredient, tirzepatide, they contained insulin.

The Health Products Regulatory Authority (HPRA) warned that if administered, users could develop severe hypoglycaemia, a life-threatening condition caused by low blood sugar.

The HPRA and Revenue’s Customs Service confiscated the pens, which were sent by post to Ireland and originated from outside of Europe.

The package included a mix of counterfeit injections, lab tests confirmed that two of the pens contained insulin.

The HPRA said that, to date, no reports of harm have been received in connection with this issue, nor is there evidence that these particular counterfeit products have reached end users.

It is advising members of the public to “only source prescription medicines from a registered pharmacy using a valid prescription to ensure they are accessing legitimate authorised medicinal products.”

Tirzepatide v insulin

The ingredients act in different ways, and if used together they can cause dangerously low blood sugar.

Tirzepatide is a manufactured peptide designed to help manage type 2 diabetes and support weight loss by encouraging the body to create insulin, while insulin injections act directly replace natural insulin.

The high price of weight-loss injections in Ireland has resulted in some users looking towards the black market for the medication.

Experts have previously warned that accessibility to the medication should be improved to prevent this safety risk, particularly given the recent price hike of the medication in the UK.

The HPRA said it detained almost 400,000 units of illegal medicines in the first half of 2025.

It said prescription medicines from unregulated sources means you can’t be sure what you’re getting.

“These products may be unsafe, ineffective, or fake – and could seriously harm your health,” it said.