A new study has highlighted the most common side effects of weight loss jabs
A groundbreaking study has identified some of the most frequently reported side effects of weight loss injections. Research found that almost half of participants using GLP-1 inhibitors were experiencing problems.
GLP-1 (glucagon-like peptide-1) is a naturally occurring gut hormone that regulates blood sugar levels and appetite. The use of GLP-1 inhibitors, or receptor agonists, has rocketed in popularity in recent years owing to their proven effectiveness in managing blood sugar levels in diabetic patients and supporting weight loss.
Available in injectable form, some of these drugs can be prescribed through the NHS to eligible patients. However, as with all medications, health authorities have cautioned that they can trigger side effects.
A new study has now drawn on anecdotal evidence from patients to pinpoint the most widespread side effects associated with the jabs. The research, published in Nature Health, used artificial intelligence to scrutinise social media posts, uncovering patient-reported side effects linked to these medicines that may not yet have been examined in clinical trials.
The study analysed more than 400,000 Reddit posts from nearly 70,000 users discussing GLP-1 receptor agonists, including semaglutide and tirzepatide. Among the most commonly reported side effects were gastrointestinal complaints, which are already flagged by health bodies such as the Medicines and Healthcare products Regulatory Agency (MHRA).
The research also drew attention to reproductive symptoms, including irregular menstrual cycles and unexpected bleeding, alongside temperature-related issues such as chills, hot flushes, and feeling unusually cold. Additionally, fatigue emerged as a frequently reported symptom, despite receiving less prominence in clinical trial data.
Senior author Dr Sharath Chandra Guntuku, from the University of Pennsylvania, said: “Some of the side effects we found, like nausea, are well known, and that shows the method is picking up a real signal. The underreported symptoms are leads that came from patients themselves, unprompted, and clinicians could potentially pay attention to them.”
What were the most commonly reported side effects?
Within the study, a total of 67,008 Reddit users self-reported using these medications. Of these, 43.5 per cent described at least one side effect.
These included:
- Nausea (36.9 per cent)
- Fatigue (16.7 per cent)
- Vomiting (16.3 per cent)
- Constipation (15.3 per cent)
- Diarrhoea (12.6 per cent)
Study authors added: “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. Large-scale social media analysis can complement traditional pharmacovigilance by detecting emerging safety signals and expanding understanding of the real-world safety profile of GLP-1 RAs.”

You must be logged in to post a comment Login