Scientists discover two weight loss jab side effects not officially listed by manufacturers
Weight loss jabs might be more popular than ever but users often have to contend with a wide range of side effects.
Drugs such as Ozempic, Mounjaro and Wegovy are all in demand from people looking for a seemingly quick and easy way of losing weight, despite the medications being initially designed as a treatment for Type 2 diabetes.
Since celebrities first started being honest about using them, we've heard about all sorts of side effects, with Jeremy Clarkson very vocal about the way Ozempic affected his body.
Symptoms such as nausea, diarrhoea and fatigue have all been heavily reported, while there do also seem to be some positive side effects, particularly when it comes to heart health.
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However, scientists who analysed posts from nearly 70,000 Reddit users between 2019 and 2025 have now identified some of the other common symptoms that have been reported on social media, some of which aren't listed by manufacturers.
Published in the journal Nature Health, they found nausea (36.9 per cent), fatigue (16.7 per cent), vomiting (16.3 per cent), constipation (15.3 per cent) and diarrhoea (12.6 per cent) were the most frequent symptoms reported.
However they wrote that 'notably, reproductive symptoms, for example, menstrual irregularities and temperature-related complaints, for example, chills and hot flushes, emerged as unrecognised potential effects'.
“These findings highlight patient concerns not well captured in current labelling or trials.”
Neil Sehgal, study lead author and doctoral student in computer and information science at the University of Pennsylvania, made it clear that this does not represent a confirmation that the GLP-1 drugs are causing these symptoms.
However, he added that it's a 'signal worth investigating', as 'nearly four per cent of the Reddit users in our sample reported menstrual irregularities, which would be even higher in a female-only sample.
Professor Lyle Ungar, a professor of computer and information science at the University of Pennsylvania, added: “Clinical trials generally identify the most dangerous side effects of drugs.
“But they can fail to find what symptoms patients are most concerned about – even though social media is not necessarily representative, a large collection of posts may reflect additional concerns.
“We don’t really know yet whether what we’re seeing on Reddit reflects the experience of GLP-1 users globally, or whether it’s particular to the kind of person who posts on Reddit in the United States.”
The scientists suggest that using AI to monitor social media and comments could become a good way of identifying early warning signs from drugs which might not have been picked up in trials.
This could be particularly important when it comes to the sale of GLP-1 medications, many of which are purchased from online pharmacies without proper prescriptions, since they are only currently available to people who meet strict guidelines here in the UK.
Meanwhile, it seems as if the drugs will only become more popular, with a ground-breaking pill version set to be released soon.
A spokesperson for Eli Lilly, the manufacturer of Mounjaro, told LADbible: "Patient safety is Lilly’s top priority, and we take any reports regarding patient safety seriously. Regulatory agencies conduct extensive independent assessments of the benefits and risks of every new medicine and Lilly is committed to continually monitoring, evaluating, and reporting safety data to ensure the latest information is available for regulators and prescribers.
"We encourage patients to consult their doctor or other healthcare professional regarding any possible side effects they may be experiencing and to ensure that they are getting genuine Lilly medicine."
LADbible has contacted Novo Nordisk for comment.
James Moorhouse