GLP-1s, the newest class of obesity medications, have soared in popularity for their ability to help people lose weight. They may have additional health benefits, research shows.
GLP-1 drugs have been available since 2005 to treat type 2 diabetes. Now, a handful of them are approved by the FDA to treat obesity. These medications include semaglutide (called Ozempic or Rybelsus when prescribed for diabetes, Wegovy for obesity), liraglutide (Victoza/Saxenda), and a closely related drug called tirzepatide (Mounjaro for diabetes, Zepbound for obesity). Several more are in the approval pipeline.
These drugs work by mimicking gut hormones that slow down digestion and lower blood glucose after you eat. Experts think they also lessen cravings by acting on certain areas of the brain. This has been a game changer for people who have struggled to lose weight despite doing their best with diet and exercise.
The benefits of these drugs seem to go even deeper than weight loss. They have been shown to lower blood pressure, improve lipid disorders and fatty liver disease, and reduce the risk of heart and kidney disease.
GLP-1 Drugs May Protect Organs
Researchers have known for a long time that these medications can reduce inflammation and scarring and potentially protect our organs, says Katherine Tuttle, MD, a kidney disease specialist at the University of Washington and the executive director for research at Providence Health Care in Spokane, WA.
She helped lead a 2019 clinical trial called FLOW, which included people who had both type 2 diabetes and serious chronic kidney disease, a common complication of diabetes. People in the study either got semaglutide once a week or a placebo. After an average of about 3.5 years, people in the semaglutide group were 24% less likely to have a major kidney disease event such as dialysis, transplant, or kidney-related death, compared to those who got the placebo. People in the semaglutide group were also 20% less likely to die from any cause during the study period.
“We’ve never seen anything like this before,” Tuttle says. “The potential impact on the public’s health is enormous.”
People on semaglutide were also 20% less likely to have a heart attack and stroke during the study. In fact, the drugs were so good at reducing cardiovascular risk and improving kidney health that the researchers stopped the study early. “Basically, it was not ethical to continue giving people placebo,” Tuttle says. These effects were independent of whether someone lost weight.
Anti-inflammation, Anti-Scarring Effects
Most types of kidney and heart disease share many risk factors, such as diabetes and high blood pressure, Tuttle says. These factors can cause inflammation in the body, as well as fibrotic scarring, which is when the tissues of your organs become thicker and stiffer over time in response to damage.
GLP-1s work partly by improving those risk factors, Tuttle says. Weight loss can sometimes help counter inflammation and fibrosis. But the GLP-1s also appear to have anti-inflammatory and anti-fibrotic effects that can protect the organs directly, even without weight loss.
When you protect one organ system, Tuttle notes, you often protect another. For instance, she points out that when a kidney fails, it’s bad for the heart and when someone has heart failure, it compromises the kidneys. “It’s pretty amazing that the drugs, in some ways, seem to break that cycle.”
The anti-inflammatory effects also appear to protect other areas of the body from damage, including the brain. Chronic inflammation plays a role in a wide array of brain disorders, including Alzheimer’s, multiple sclerosis, schizophrenia, epilepsy, and more. Many preclinical studies have shown that GLP-1s can reduce brain inflammation. Other studies have shown that semaglutide may improve cognitive function and possibly reduce risk of dementia. Researchers are working hard to find out exactly how this happens, and whether this means these drugs can be used safely to treat neurological diseases.
GLP-1 and Addiction
In addition to controlling inflammation, GLP-1 drugs seem to act directly on brain pathways that have to do with pleasure and reward, says obesity medicine specialist Michelle Rappaport, MD, the medical director for Swedish Weight Loss Services in Seattle. While this research is still preliminary, if it pans out, it could have big implications for addiction treatment. Semaglutide studies have shown that the drugs interact directly or indirectly with multiple different brain areas related to food intake. “I don’t think it’s surprising that some of those pathways might overlap with addiction,” Rappaport says.
She says that some of her patients struggle not to think about food to the point that it distracts them from their work. But when they start taking a GLP-1, they say they feel as if that tunnel vision surrounding food has been removed. “I think that’s really a benefit – the quieting of ‘food noise,’” Rappaport says.
She’s also noticed that her patients taking GLP-1 medications often don’t crave alcohol as much as they used to. People may find that their tolerance for alcohol is lower, perhaps because the medicines slow down how quickly the stomach empties, she says. This is part of why the drugs work for weight loss: They make people feel full faster. People taking these medications may also get more unpleasant effects from drinking, such as heartburn or stomach upset, making alcohol less pleasurable, Rappaport says.
People also often report simply not caring about drinking alcohol anymore, she says. Just as the drugs appear to help quiet “food noise,” early clinical data from studies done in lab animals suggest that these medications may be able to curb compulsive drinking habits, as well as the use of nicotine and other drugs, including opioids. But research is needed to confirm that this holds up in people. Some surveys, social media studies, and anecdotes from doctors show that people report drinking less alcohol while taking GLP-1 drugs. Researchers are working to find out exactly why that happens.
Related news story: Small Study Raises hopes for Semaglutide Treatment of Alcoholism
Side Effects
For all their potential benefits, GLP-1s aren’t a silver bullet, and researchers are still studying side effects, as well as long-term effects on the body. Common side effects include nausea, vomiting, and diarrhea, especially when you first start taking the medication or if you’re on a higher dose. Some people may also have:
- Dizziness
- Increased heart rate
- Infections
- Headaches
- Upset stomach
- Injection site issues
Other rare but severe possible side effects can include pancreatitis, medullary thyroid cancer, sudden kidney injury, and worsening diabetes-related retinopathy.
Some of the newer, more effective drugs in the pipeline have particularly high rates of certain side effects, Rappaport says, “like, 30% of people vomiting in some cases.” She recommends being wary of online prescribers who sometimes sell full doses of these medications without a doctor’s visit. “We will see a lot of ER visits for IV hydration and kidney injury from dehydration from these medications if we don’t have more responsible prescribing,” she says.
Researchers have also stressed that while the medications appear to be relatively safe, the long-term effects are not yet well known. Having a relationship with a doctor who can assess you and follow you over time is extremely important, Tuttle says, especially in light of the high prices for these drugs.
Access Problems
The potential for GLP-1 drugs is clear. “I think these [medications] need to become first-line therapies for people with diabetes and kidney disease,” Tuttle says. But cost and availability are major hurdles, and insurance (including Medicare and Medicaid) don’t always cover them.
Conditions such as diabetes, obesity, and kidney disease are often concentrated in groups that are at a socioeconomic disadvantage, Tuttle notes. “The people who need it as a kidney- and heart-saving therapy are the people who may be least able to access it,” she says. “This is the next big issue to confront. How do you make the drug available to all people who could benefit, not just the privileged few?”
