You’ve probably heard of Ozempic or Wegovy. These are the injectable drugs that have become household names for weight loss and diabetes.
Now, researchers are investigating whether these drugs, known as GLP-1 agonists or GLP-1 drugs, could treat everything from cancer and brain disease to depression, addiction and endometriosis.
Some findings are truly fascinating. Others are oversold. Here’s what the science actually says.
First, how do these drugs work?
GLP-1 (glucagon-like peptide-1) is a hormone that your gut naturally releases after you eat. It tells your pancreas to produce insulin and signals your brain that you are full. These drugs mimic this hormone.
But GLP-1 receptors aren’t just in the gut. They are found in the heart, kidneys, liver and brain. This is what leads scientists to believe that these drugs may do much more than just manage weight.
Read more: The rise of Ozempic: how surprise discoveries and lizard venom led to a new class of weight loss drug
Where the evidence is already solid
Beyond diabetes and obesity, GLP-1 drugs have now received regulatory approval in several new areas.
A testing more than 17,000 people found that semaglutide (the active drug in Ozempic/Wegovy) reduced the risk of major heart attacks and strokes by 20%, even in people without diabetes.
In one trial of nearly 1,200 patientssemaglutide outperformed placebo in treating a type of advanced liver disease.
Tirzepatide (Mounjaro) has also been shown to be significant reduce the severity of sleep apneamainly because weight loss puts less pressure on the airways.
GLP-1 and cancer: promising but no clinical trial evidence
Obesity is a risk factor for at least 13 cancerstherefore weight reduction using GLP-1 drugs may also be expected to reduce cancer risk. This was seen in a study of 86,000 adults with obesity. It found that GLP-1 users had a 17% lower risk of cancer.
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, there have not yet been well-controlled clinical trials proving the link between GLP-1 drugs and cancer prevention.
Endometriosis: early but promising signs
Endometriosis affects approx one in ten women of reproductive age. This is where tissue similar to the lining of the uterus grows outside the uterus.
Because GLP-1 receptors are also present in reproductive tissue, these drugs have shown promise in improving symptoms, with survey of 161 women supporting this.
But, similar to cancer, there are no randomized trials in humans.
Haberdoedas/Unsplash
Addiction and smoking
GLP-1 receptors are concentrated in the brain’s reward pathways. These same circuits cause 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 poisoning.
A randomized trial found that semaglutide reduced alcohol consumption in people with alcohol use disorder.
Early smoking cessation trials they are also encouraging.
The brain: the less clear picture for GLP-1 therapy
This is where the story gets really complicated.
There are real biological reasons that GLP-1 drugs could help with neurodegeneration and mental illness. They reduce brain inflammation, interact with dopamine (the brain’s motivation chemical), and support the gut-brain axis (the communication network that carries signals to and from the gut and brain).
However, current clinical evidence is conflicting.
For Alzheimer’s disease, the researchers recruited 204 participants with mild to moderate disease liraglutide (a GLP-1 that predates Ozempic) and measured how much brain volume they lost. Those who received the drug showed significantly less shrinkage in key areas of the brain, including the temporal lobe and overall gray matter.
However, a large phase 3 trial of oral semaglutide found that it was not effective in slowing the clinical progression of the disease.
Similarly, exenatide (another older GLP-1) showed no evidence of disease modification in 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.
But a special one observational study found that people taking these drugs had almost twice the risk of major depression.
Other paper found that people with a genetic tendency toward low dopamine levels may face a higher risk of depression and suicidal thoughts with these drugs.
There are also case reports severe psychiatric episodes occurring within weeks of starting treatment.
We don’t yet know who these drugs will help and who they could seriously harm.
Read more: Taking a drug like Ozempic? What you need to know about the risks of suicidal thoughts and contraceptive failure
What should we watch out for?
Importantly, most of the new uses for these drugs have yet to be tested in proper clinical trials. Large real-world studies are useful but cannot rule out critical confounders. This means that the results may be due to external influences.
For example, most major GLP-1 trials have enrolled subjects with obesity or diabetes. People with mental illness, neurodegenerative diseases or addiction were largely excluded. However, these are the very populations that are now being considered for treatment.
The long-term effects are also unknown. A study of more than 200,000 patients found a 2-2.5 times higher risk of drug-induced pancreatitis (dangerous inflammation of the pancreas).
Rapid weight loss also strips away lean muscle, not just fat, affecting strength and metabolism, especially in older adults.
Studies have also shown that these drugs carry a risk of thyroid cancercausing a warning on drug labels, but the evidence is excellent contradictory.
Time and further research will tell, but there are real safety concerns associated with the widespread use of these drugs.
So while the science here is really exciting, we should continue to approach with informed caution.
Read more: Mounjaro is more effective for weight loss than Ozempic. So how does it work? And why does it cost so much?
