You have likely heard of Ozempic or Wegovy. These injectable drugs have become household names for weight loss and diabetes management. Now, researchers are investigating whether these medications, known as GLP-1 agonists or GLP-1 drugs, could treat conditions ranging from cancer and brain disease to depression, addiction, and endometriosis. Some findings are genuinely exciting, while others are being oversold. Here is what the science actually says.
How Do These Drugs Work?
GLP-1 (glucagon-like peptide-1) is a hormone naturally released by your gut after eating. It signals your pancreas to produce insulin and tells your brain that you are full. These drugs mimic that hormone. However, GLP-1 receptors are not only found in the gut; they are present in the heart, kidneys, liver, and brain. This is why scientists believe these drugs might do far more than manage weight.
Where the Evidence Is Already Solid
Beyond diabetes and obesity, GLP-1 drugs have earned regulatory approval in several new areas. A trial involving more than 17,000 people found that semaglutide (the active drug in Ozempic and Wegovy) reduced the risk of serious heart attacks and strokes by 20%, even in individuals without diabetes. In a trial of almost 1,200 patients, semaglutide outperformed a placebo in treating a type of advanced liver disease. Tirzepatide (Mounjaro) has also been shown to significantly reduce the severity of sleep apnoea, largely because weight loss relieves pressure on the airways.
GLP-1s and Cancer: Promising but No Clinical Trial Evidence
Obesity is a risk factor for at least 13 cancers, so reducing weight with GLP-1 drugs can be expected to lower cancer risk. A study of 86,000 adults with obesity found that GLP-1 users had a 17% lower cancer risk. New data suggests that GLP-1 users were also less likely to see cancer spread to other organs, but this work has yet to be verified by other researchers. The anti-inflammatory effects of these drugs, which appear to work independently of weight loss, may play a role. However, no well-controlled clinical trials have yet established a direct link between GLP-1 drugs and cancer prevention.
Endometriosis: Early but Promising Signs
Endometriosis affects roughly one in ten women of reproductive age, where tissue similar to the womb lining grows outside the uterus. Because GLP-1 receptors are also present in reproductive tissue, these medications have shown promise in improving symptoms, supported by a survey of 161 women. However, similar to cancer, there are no randomised human trials yet.
Addiction and Smoking
GLP-1 receptors are concentrated in the brain's reward pathways, which drive cravings for alcohol, nicotine, and drugs. An analysis of more than 1.3 million people found that GLP-1 users had significantly lower rates of opioid overdose and alcohol intoxication. A randomised trial found that semaglutide reduced drinking in people with alcohol use disorder. Early quit-smoking trials are also encouraging.
The Brain: The Least Clear Picture for GLP-1 Therapy
This is where the story becomes genuinely complicated. There are real biological reasons why GLP-1 drugs could help with neurodegeneration and mental ill-health. They reduce brain inflammation, interact with dopamine (the brain's motivation chemical), and support the gut-brain axis. However, current clinical evidence is conflicting. For Alzheimer's disease, researchers gave 204 participants with mild to moderate disease liraglutide (a GLP-1 that predated Ozempic) and measured brain volume loss. Those taking the drug showed significantly less shrinkage in key brain regions, including the temporal lobe and overall grey matter. However, a large phase 3 trial of oral semaglutide found it was not effective at slowing clinical disease progression. Similarly, exenatide (another earlier GLP-1) showed no evidence for disease modification in a phase 3 Parkinson's disease trial.
For mental health, current evidence is also mixed. Meta-analyses and large cohort studies show significant reductions in depression and anxiety scores among GLP-1 users. However, a separate observational study found that people on these drugs had almost double the risk of major depression. Another paper found that people with a genetic tendency toward low dopamine levels may face a higher risk of depression and suicidal thoughts on these medications. There are also case reports of serious psychiatric episodes appearing within weeks of starting treatment. We do not yet know who these drugs will help and who they could seriously harm.
What We Need to Be Cautious About
Crucially, most of the new uses for these medications have not yet been tested in proper clinical trials. Large real-world studies are useful but cannot rule out crucial confounding factors, meaning the effects may be due to external influences. For example, most major GLP-1 trials have enrolled people with obesity or diabetes, while those with mental health conditions, neurodegenerative diseases, or addiction were largely excluded. Yet these are the very populations now being considered for treatment.
Long-term effects are also unknown. A study of more than 200,000 patients found a 2 to 2.5 times higher risk of drug-induced pancreatitis (dangerous inflammation of the pancreas). Rapid weight loss also strips lean muscle, not just fat, affecting strength and metabolism, especially in older adults. Studies have also indicated a risk for thyroid cancer, prompting a warning on drug labels, but the evidence is highly conflicting. Time and further research will tell, but there are genuine safety concerns associated with the widespread use of these medications. So, while the science here is genuinely exciting, we should continue to approach with informed caution.
