GLP-1 receptor agonists, such as Ozempic and Mounjaro, have been hailed as breakthroughs against obesity and diabetes. But now, the Australian regulator Therapeutic Goods Administration (TGA) has issued a class-wide warning: mood changes, depression, even suicidal thoughts or behaviours have been reported.

Simply put: these drugs don’t act only where you want them to. Their receptors exist across many parts of the body, brain, heart, kidneys and more. That broad reach means that while they suppress appetite or cravings, they might also blunt deeper drives: thirst, libido, even life’s motivations.

Some studies show elevated risks of depression or suicidal ideation in people with pre-existing mental-health issues. Others, including one large study by National Institutes of Health, found no increased risk compared to other drugs.

The contradiction is not surprising. Clinical trials tend to be short and narrow; they may miss rare, long-term or cumulative effects. But people who take these drugs for months or years may experience subtle shifts, in mood, drive, or desire, that go undetected in trials.

If you or someone you know is on a GLP-1 regimen, taking note of changes in mood, energy, interest or closeness with others is vital. Be honest with your doctor. Ask for independent data, not just company-funded studies. Because sometimes, the cost of “feeling lighter” could be far heavier than expected.