The rise of GLP-1 drugs such as Ozempic and Mounjaro has been nothing short of meteoric. Originally developed to treat diabetes, these drugs are now widely used for weight loss and have become household names. However, alongside headlines of dramatic transformations are reports of an increased risk of suicidal thoughts and unwanted pregnancies after contraception failures.
Australia’s Therapeutic Goods Administration (TGA) has issued new warnings this week about these potential side effects, urging caution among users. The announcement comes as more individuals turn to these medications for weight management, raising questions about their safety.
Understanding GLP-1 Drugs
Glucagon-like peptide-1 (GLP-1) drugs are medicines used to treat type-2 diabetes and obesity. They work by reducing blood sugar levels and suppressing appetite. In Australia, five medicines in this category are approved for use:
- Mounjaro (tirzepatide)
- Ozempic (semaglutide)
- Wegovy (semaglutide)
- Saxenda (liraglutide)
- Trulicity (dulaglutide)
These drugs have been available for the past decade but surged in popularity recently, partly due to endorsements by Hollywood celebrities. While the most common side effects are related to digestion, such as nausea and vomiting, more serious concerns have emerged.
Suicidal Thoughts: A Growing Concern
In the 12 months to November 2025, there were 20 cases of suicidal thoughts reported in the Australian Database of Adverse Events Notifications that coincided with the use of a GLP-1 medicine. This aligns with a 2024 study that found a link between GLP-1 medicines and a 106% increase in the risk of suicidal behavior.
A 2024 study found a link between GLP-1 medicines and a 106% increase in the risk of suicidal behavior.
However, not all evidence supports this link. A separate study from 2024 analyzed data from over 1.8 million patients and found a lower risk of new or recurring suicidal thoughts among those taking GLP-1 drugs compared to those who were not.
Impact on Contraception
Oral contraceptives work by using hormones to prevent the release of eggs from the ovaries and to thicken cervical mucus. If GLP-1 medicines affect hormone absorption, contraceptive effectiveness may be compromised. Researchers first raised this concern in 2003.
The impact of GLP-1 medicines on oral contraceptives may vary. A review found that tirzepatide had a higher impact on hormone absorption compared to other GLP-1 drugs. Conversely, a 2015 study indicated that semaglutide did not affect hormone levels in commonly used oral contraceptives.
GLP-1 drugs should not affect the efficacy of IUDs or other long-acting contraceptives as they are not reliant on hormones being absorbed from the stomach.
Guidance for Current Users
The TGA recommends that individuals taking GLP-1 medicines report any new or worsening depression, suicidal thoughts, or unusual mood changes to their doctor. For women using tirzepatide and oral contraceptives, the TGA advises switching to a non-oral contraceptive or adding a barrier method for four weeks after starting or increasing the dose of tirzepatide.
Additionally, GLP-1 drugs should not be used during pregnancy due to potential impacts on fetal growth. The adverse events database has reported cases of miscarriages in women taking semaglutide or tirzepatide during pregnancy.
If this article has raised issues for you, or if you’re concerned about someone you know, call Lifeline on 13 11 14 or the Suicide Call Back Service on 1300 659 467.
This material from the originating organization/author(s) might be of the point-in-time nature, and edited for clarity, style, and length. Mirage.News does not take institutional positions or sides, and all views, positions, and conclusions expressed herein are solely those of the author(s).
