What the latest research says about GLP-1s in 2025

Now used by millions, GLP-1 agonist drugs like Wegovy are also being studied for everything from weight loss to gambling addiction. Here’s what we know now.

WRITTEN BY

Julie Stewart

Updated: 12/05/2025|8 min read

GLP-1 receptor agonists have exploded in popularity, with prescriptions increasing by 364 percent between 2019 and 2024. Medicare and Medicaid could soon cover these medications, further expanding their use.

Since their initial public release in 2005 as diabetes drugs—and in the last decade, their widespread use for weight loss—researchers have continued to probe the long-term health effects of GLP-1 receptor agonists.

Today, the body of research is in its teenage years and rapidly expanding. Researchers published hundreds more papers on GLP-1 receptor agonists in 2024 than in 2023, and 2025 is on pace to be the biggest year yet for GLP-1 studies.

So far, scientists are finding both benefits and drawbacks to these drugs. A recent study review published in Nature Medicine suggests that GLP-1s could be linked to as many as 175 different health outcomes, both positive and negative. The weight-reducing, blood-sugar-lowering, inflammation-tamping effects of GLP-1 receptor agonists appear to translate into other health improvements in several studies. However, sometimes these drugs cause side effects that can negatively impact quality of life.

Here’s what the latest research tells us.

GLP-1s and weight loss

Well-established as weight-loss treatments, these medications work by stimulating receptors for the hormone glucagon-like peptide 1 (GLP-1) to suppress hunger. GLP-1 receptor agonists also support weight loss by:

• Enhancing insulin secretion to improve blood sugar control
• Reducing the release of glucagon (a hormone that raises blood glucose levels)
• Slowing the movement of food through your gastrointestinal system
• Regulating gut hormones
• Curbing inflammation
• Reducing deposition of body fat in organs and tissues not meant to store fat
• Possibly altering taste perception to make food less appetizing

As more people try these medications, we’re learning more about how to maximize their weight-reducing benefits. Below are a few recent lessons.

1. These drugs work when you stick with them

A study review published in Diabetes, Obesity and Metabolism in April suggests that weight loss on GLP-1s can range from 2.2 to 21.2 percent over six months to a year, with the best outcomes after a year of consistent use.

Some people regain significant amounts of weight if they stop the medication. Research published in Diabetes, Obesity and Metabolism found that people lost 17.3 percent of their body weight when they used a GLP-1 agonist. But after quitting the drug, they regained 11.6 percentage points of lost weight in a year, bringing their net loss to 5.6 percent over a 120-week period.

We need more long-term studies to determine whether rebound weight gain is avoidable, including whether lifestyle interventions can stave off weight gain or if you need to take GLP-1s forever to prevent weight gain. One recent study found that people started gaining weight about eight weeks after stopping their medication. The metabolic effects of GLP-1s go away when you stop taking the drugs, the researchers say, and the reduction in GLP-1 receptor agonist activity could lead to weight regain.

2. Most of the weight lost is fat, not muscle

About 25 percent of the weight lost with GLP-1s is lean mass, such as muscle, suggests a review of studies published in Metabolism in March. (People lose similar amounts of muscle when dropping pounds through other methods.)

However, relative lean mass—the proportion of lean mass over time—stayed consistent in the study. That means fat-to-muscle ratio remains the same—or, it could improve, suggests a new review published in the European Journal of Pharmacology. Eating plenty of protein and doing resistance training can help preserve muscle while you take a GLP-1, scientists suggest. Yet a recent survey reports that many people taking GLP-1s don’t consume enough protein (about 0.5 to 0.9 grams per pound of body weight per day) to maintain muscle mass on a low-calorie diet.

3. Microdosing is still an open question

Many health influencers tout microdosing—taking smaller-than-usual doses of GLP-1s for weight loss or maintenance. According to one recent survey, more than one-third of GLP-1 users follow this practice, which is especially popular among Gen Z. However, microdosing hasn’t been studied in clinical trials, so there’s no reliable data to suggest how well it works. One mathematical modelling study suggests that taking semaglutide or tirzepatide every two weeks instead of weekly could help maintain 75 percent of the weight lost.

Doctors say microdosing could be helpful if you’re looking to:

• Smooth the transition when switching GLP-1 medications or doses
• Lower out-of-pocket medical costs
• Stay on your medication during drug shortages or adjust to very-low-calorie diets

Microdosing could also curb gastrointestinal side effects. GLP-1s increase the risk of nausea, vomiting, diarrhea, and constipation. Higher doses were associated with more side effects and higher odds of stopping treatment in clinical trials.

To microdose safely, doctors say, pay attention to the shelf life of opened pens, store them properly, and use a new needle with each injection. Most importantly, maintain communication with your healthcare providers.

The other health benefits of GLP-1s

When people lose weight with GLP-1s, their health can improve in other ways as well. Many of these benefits relate to weight loss, but studies are underway to understand how these medications might affect health through additional mechanisms. For example, research suggests GLP-1s might impact reward circuits in the brain to influence behavior. They might also curb inflammation, a root cause of almost every disease. Here are a few of the benefits science has found so far.

Cancer risk

Using a GLP-1 might help lower cancer risk. A review of health records published in eClinicalMedicine found similar rates of obesity-related cancers in people treated with GLP-1s versus bariatric surgery. But in a model adjusting for the greater weight loss achieved with surgery, GLP-1s were associated with a 41 percent lower relative risk of obesity-related cancers. Some researchers credit GLP-1s’ ability to reduce inflammation, which promotes cancer cell growth and spread.

Another recent study in JAMA Oncology showed that taking GLP-1s was associated with a 25 percent reduced risk of endometrial cancer, a 31 percent reduced risk of meningioma, and a 47 percent reduced risk of ovarian cancer. Obesity and high blood sugar are risk factors for endometrial cancer, which has been linked to metabolic and hormonal pathways. Studies of tumors show that many meningiomas express GLP-1 receptors and might respond to GLP-1 medications. And research in ovarian cancer cells suggests that GLP-1s might reduce the activity of metalloproteinases, enzymes that enhance tumor growth.

Heart health

GLP-1s might improve heart health by reducing blood sugar, blood pressure, and oxidative stress that would otherwise harm cardiac cells. A new review published in Diabetes Care found that people with Type 2 diabetes (a group at heightened risk of heart problems) who used a GLP-1 had a 14 percent lower risk of major cardiovascular events. GLP-1 users also had a 14 percent lower risk of hospitalization for heart failure, a 17 percent reduced risk of major kidney complications, and a 12 percent reduced risk of all-cause mortality.

GLP-1s also lower heart disease risk in people who have obesity but not diabetes, according to new research published in the Journal of Diabetes. GLP-1s reduced the risk of major cardiovascular events by 20 percent compared to placebo.

Liver health

The FDA recently approved the GLP-1 receptor agonist semaglutide (Wegovy) for the treatment of metabolic-associated steatohepatitis (MASH), a severe form of fatty liver disease that causes inflammation and scarring. Untreated, MASH can progress to liver failure, cancer, or death. The drug was approved based on research showing that 63 percent of people who took semaglutide cleared their MASH within 72 weeks compared to 34 percent of people taking a placebo. The study is continuing for another 168 weeks to assess long-term effects.

“Wegovy promotes weight loss and potentially other mechanisms not fully understood, which may improve liver inflammation and scarring,” the FDA said in its approval notice.

Other GLP-1s might also protect the liver. A new study review found that patients who used any one of eight GLP-1s reduced their liver fat by 5 percent in about 24 weeks. The medications also improved a wide range of liver markers, including liver stiffness.

Brain health

GLP-1s might protect against age-related brain degeneration in specific populations. In a new study published in JAMA Network Open, people with Type 2 diabetes and obesity (both risk factors for neurodegeneration) who took GLP-1s had lower risks of dementia and strokes than people who received other diabetes treatments. GLP-1s might help protect neurons in ways that aren’t yet understood, the researchers say. These medications might thwart strokes by preventing blockages in small blood vessels in the brain. A study review suggests that GLP-1s might reduce stroke risk in people without diabetes, too.

Sleep apnea

Tirzepatide (Zepbound) is now FDA-approved for obesity with moderate to severe obstructive sleep apnea (OSA), a sleep disorder that causes low oxygen at night. The approval is based on research showing that 52 weeks of treatment with tirzepatide reduced study participants’ apnea or hypopnea events (losses of oxygen at night) compared to placebo. “The improvement… in participants with OSA is likely related to body weight reduction with Zepbound,” according to the FDA approval notice.

Although more research is needed, other GLP-1s might also improve sleep apnea. A recent meta-analysis that included studies with tirzepatide, liraglutide, and exenatide showed that the medications reduced apnea events. The researchers say weight loss and other mechanisms, such as improved blood sugar control, fewer diabetes complications, and a reduction in fat around upper airways, may contribute to this benefit.

The downsides of GLP-1s

Despite all the benefits we hear about, GLP-1s also have some drawbacks.

Oral health

Despite people talking about “Ozempic teeth,” marked by dry mouth and tooth decay, research is limited. In an extensive review of adverse event reports, dry mouth was far more common than expected for GLP-1 drugs—about 3 times higher than typical for semaglutide, and modestly higher for liraglutide and exenatide. This condition can contribute to tooth decay because saliva contains natural buffers that protect against acids and bacteria that erode teeth.

However, for people with diabetes and gum disease—which often go together, due in part to elevated glucose in saliva—GLP-1s might be helpful, suggests research published in the Journal of Periodontal Research. In vitro studies, animal studies, and one human study suggest that GLP-1s might curb gum inflammation and protect against bone loss around the gums. The researchers say these medications might even promote healing from periodontal or dental implant procedures. GLP-1s might act on signaling pathways that help stem cells in bone marrow regenerate the periodontal bone tissue that supports teeth, they suggest.

Skin health

“Ozempic face” is probably real. Rapid weight loss—using GLP-1s or other methods—can make skin look saggier and older. One reason is that when you lose fat that lies just beneath the skin on your face, any existing wrinkles look more pronounced than they did before, researchers say. However, experts believe GLP-1s might accelerate skin aging beyond the effects of fat loss. For example, GLP-1s might stimulate GLP-1 receptors in skin’s fibroblasts, impairing their ability to protect themselves from oxidative damage and produce new collagen, a structural protein in skin, suggests a study review published in Endocrine.

Still, the news about GLP-1s and skin isn’t all bad. Some research suggests these medications can improve some inflammatory skin conditions, such as psoriasis and hidradenitis suppurativa, which causes boils where skin rubs together.

Hair loss

Social media is buzzing with stories of people who lost hair while taking GLP-1s. While research is scarce, the FDA has received more than 1,000 reports of hair loss related to the medications. One theory is that GLP-1s might disrupt the hair follicle cycle to promote shedding rather than regrowth. Accelerated skin aging might also affect hair follicles, researchers say.

Mixed results with GLP-1s

With all the emerging data, there’s still uncertainty about some of GLP-1's effects.

Eye health

High blood sugar can harm the tiny blood vessels in your eyes and threaten your vision, which is why eye complications are common in people with diabetes. Since GLP-1s reduce blood sugar, they might help protect your eyes—but it’s complicated.

In a study published this summer in JAMA Ophthalmology, people with Type 2 diabetes who took GLP-1s had double the risk of developing neovascular age-related macular degeneration than those who didn’t. Another study published a month earlier in JAMA Network Open found that people with Type 2 diabetes who used GLP-1s had a slightly increased risk of diabetic retinopathy. One theory for both effects is that rapid glucose reduction might initially worsen the health of blood vessels in the eyes.

However, the upside is that people with diabetic retinopathy who took GLP-1s developed fewer serious, sight-threatening complications—including blindness—than those who didn’t. The medications also improved blood sugar control and cardiovascular and kidney health, protecting the eyes over time. The researchers say regular screening for diabetic retinopathy is important for people with Type 2 diabetes who take GLP-1s.

Recovery from knee surgery

GLP-1s might influence recovery from knee replacement surgery, suggests a new retrospective study published in the medical journal The Knee. Compared to nonusers, people who used a GLP-1 within six months before knee replacement surgery had fewer complications overall and a lower risk of readmission, deep vein thrombosis, and death in the 90 days after surgery. GLP-1 users did, however, have a higher risk of acute kidney failure in that post-surgery period.

Obesity and diabetes are risk factors for post-surgery complications because they increase inflammation and disturb blood clotting and heart function. Researchers say the weight-reducing, blood-sugar-lowering, cardioprotective benefits of GLP-1s might reduce complications. However, questions remain about how these medications affect kidney function, especially during surgery. Researchers suggest these drugs might be toxic to the kidneys when combined with other medications such as non-steroidal anti-inflammatories for pain relief. They might also promote dehydration—which harms the kidneys—by delaying gastric emptying or making users more prone to vomiting.

Are GLP-1s right for you?

If you have overweight, obesity, Type 2 diabetes, liver disease, or sleep apnea, a GLP-1 receptor agonist medication may well help you lose weight and improve your condition. It might also improve your health in other ways that are still being understood. However, like any medication, these drugs also come with risks that are still being realized and understood. Talk with your healthcare provider to weigh the risks and benefits of GLP-1s based on your health history and circumstances.

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