A recent RTÉ Investigates programme highlighted some dubious practices surrounding the sale and use of weight-loss injections. It included the online sale of a new but unapproved experimental drug called retatrutide, as well as the supply of so-called “skinny pens”.
The problem with weight-loss jabs sold by fake online pharmacies is that they may be laced with rat poison or cement which can cause seizures and even coma in recipients.
It’s all a byproduct of the incredible hype surrounding a group of breakthrough drugs called GLP-1 agonists. Semaglutide, sold under the trade names Ozempic and Wegovy, and tirzepatide, branded as Mounjaro (which will be available in Ireland early next year) are approved for use by diabetes patients to help control their blood sugar levels and for those with higher levels of obesity to lose weight. Administered as a weekly injection, they are markedly effective.
The most obvious health benefit of GLP-1 agonists is the significant amount of weight loss they trigger. That is in part because GLP-1 is an incretin, a group of hormones released by the gut after a meal that modulate the release of insulin. GLP-1 is also known to reduce gut motility and delay gastric emptying, which brings a feeling of fullness more quickly after a meal is started. This has beneficial knock-on effects on the body. Weight loss reduces insulin resistance, tissue inflammation and fat accumulation in the liver and other organs.
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Clinical trials indicate that some people receiving weight-loss jabs lose anywhere between 16 per cent and 21 per cent of their body weight. And the Select trial, which studied semaglutide effects on heart disease and stroke in patients who were overweight or obese, found a 20 per cent reduction in major adverse cardiovascular events among those treated with the drug.
Despite prescribing guidelines that limit the prescription of GLP-1 drugs to patients who have a body mass index (BMI) of over 30, or a BMI of 27 to 30 and at least one weight-related health problem, such as high blood pressure or sleep apnoea, they are sought after by people who are not obese and just want to lose a few pounds. This trend has been driven by social media and the reputed benefits experienced by celebrities.
So it’s time for a reality check about GLP-1 agonist drugs.
The first point is that these drugs do not work for everyone. One study found that up to 15 per cent of those who took the drug tirzepatide did not lose clinically significant amounts of weight. Then there is the not inconsiderable issue of side effects. The Health Products Regulatory Authority (HPRA) has stated that, from the beginning of January 2022 to the end of November 2024, it has been notified of 385 reports of suspected side effects associated with a medicine containing a GLP1 substance.
Reports suggesting a link between suicide and the new drugs have been submitted to both the European Medicines Agency and the US Food and Drugs Administration. While two recent studies published in the Journal of the American Medical Association – Internal Medicine on the risk of GLP-1 initiation and adverse mental health outcomes were reassuring, neither fully answers the question of whether these drugs are safe in those with pre-existing mental health problems.
[ Sharp increase in number of illegal weight loss drugs seizedOpens in new window ]
People with inflammatory bowel disease and pancreatitis are likely to have problems with these weight loss jabs. They may worsen symptoms or interact with the drugs used to manage the chronic conditions.
The most frequent adverse events for semaglutide compared with placebo are gastrointestinal. Nausea occurs in 38 per cent of those taking semaglutide, diarrhoea in 27 per cent of patients and vomiting in 22 per cent. Headache and dizziness also occurred more often in those taking the GLP-1 agonist.
All of which means that, even for those deemed suitable for the jabs, there are a lot of reasons to think twice before starting treatment.
Caveat emptor indeed.