Australia’s top drug regulator has issued a new safety warning over potential risks of suicidal thoughts and mood changes linked to GLP-1 weight-loss therapies, which have surged in global demand for treating obesity.
In a safety alert released on December 1, the Therapeutic Goods Administration (TGA) announced updated product warnings for GLP-1 medicines to provide consistent guidance on possible mood-related side effects. The revisions follow ongoing investigations by Australian and international authorities. Patients are urged to report any new or worsening depression, thoughts of self-harm, or unusual shifts in mood.
The TGA stressed that current evidence does not confirm these drugs directly cause psychological effects. However, it noted that mental health conditions, obesity, and the emotional impact of weight loss can interact in complex ways.
GLP-1 drugs, initially developed for type 2 diabetes, mimic gut hormones to regulate blood sugar, curb appetite, and slow digestion. In India, Eli Lilly’s Mounjaro and Novo Nordisk’s Wegovy have quickly become top-selling therapies, while in Australia the GLP-1 lineup includes Ozempic, Saxenda, Trulicity, Wegovy, and Mounjaro.
Additional Caution on Mounjaro
The TGA also highlighted a potential interaction between the GLP-1 drug tirzepatide (Mounjaro) and oral contraceptives. While evidence is not conclusive, the regulator said a reduction in contraceptive effectiveness cannot be ruled out.
Labels for tirzepatide have been updated to advise patients to switch to non-oral contraceptives or use a barrier method for four weeks after starting the drug and after each dose increase.
Experts Weigh In
Dr. Monika Sharma, senior endocrinologist at Aakash Healthcare, said the updated warnings reflect growing attention to patient safety as new data emerges on the psychological and pharmacological effects of GLP-1 drugs.
She noted that reports of mood disturbances, depressive symptoms, and rare suicidal thoughts have prompted regulators to harmonise product labels, even without a proven direct causal link. Early detection is key, she said, because sustained appetite suppression and rapid weight loss can create unexpected psychological strain for vulnerable patients.
Chennai-based diabetologist Dr. V. Mohan urged caution in interpreting early findings and stressed the need for larger studies. He noted that even after bariatric surgery, patients can experience identity changes contributing to emotional distress. Many individuals eligible for GLP-1 therapies are already at higher risk for depression and suicidal thoughts, complicating efforts to separate underlying conditions from drug effects. Severe psychiatric side effects remain relatively rare, he added.
Dr. Sharma emphasized that the revised guidelines underscore the importance of close monitoring, clear communication about mood changes, and careful evaluation of each patient’s medical and psychological history throughout treatment.
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