The difference between game-changer weight loss drugs semaglutide, tirzepatide, and liraglutide

• People were found to lose almost 16% of their body weight on the drug tirzepatide in a trial.
• Manufacturer Eli Lilly said it hopes the FDA will approve the drug for weight loss this year.

Diabetes drug tirzepatide has been shown to help people lose almost 16% of their body weight in a clinical trial, and it could soon join semaglutide and liraglutide in the ranks of buzzy weight loss medications on the market.

The trial that took place over 72 weeks involved 938 patients with type 2 diabetes who were overweight or obese, drugmaker Eli Lilly said in a press release on Thursday.

Those who took tirzepatide lost 15.7%, or 34.4 pounds, of body weight on average when compared to those on a placebo, who lost 3.3% of their weight, or 7 pounds, on average. The participants weighed 222 pounds on average at the start of the trial.

According to the press release, Eli Lilly plans to complete its submission to the FDA in the coming weeks for the drug to be approved for weight loss, which it hopes will happen late this year.

If approved, tirzepatide would join other buzzy "game-changer" drugs including semaglutide, which is marketed as Ozempic for diabetes and Wegovy for weight loss, and liraglutide, which is marketed as Saxenda for obesity and diabetes.

Semaglutide has become so popular there have been shortages, as rumors swirl around which celebrities may be using it.

These drugs are part of a family of medications known as GLP-1 agonists, which mimic a hormone released when we eat food. As well as helping the body to create more insulin, they reduce the amount of sugar the liver makes, reduce appetite, and slow down the digestion process.

Common side effects of GLP-1 agonists include nausea, diarrhea, stomach pains, constipation, lowered appetite, low blood sugar, and headaches.

Dr. M. Regina Castro of the Mayo Clinic wrote in an article for the institution's website that it is not yet certain why GLP-1 agonists help with weight loss, but they do curb hunger and can make a person eat less.

Here's how the drugs compare.

Semaglutide

Developed and manufactured by Novo Nordisk, semaglutide is a weekly injection that was approved by the FDA to treat type 2 diabetes under the name Ozempic in December 2017.

However, a trial published in the New England Journal of Medicine in 2021 involving almost 2,000 people across 16 countries found that in 68 weeks, participants lost 15% of their body weight on average on semaglutide, paving the way for it to be used as a weight loss drug.

At the time, Dr. Robert F. Kushner, lead author of the study and an obesity researcher at Northwestern University Feinberg School of Medicine who works with Novo Nordisk, called the drug a "game-changer" in an interview with The New York Times.

"This is the start of a new era of effective treatments for obesity," he said.

In June 2021, semaglutide was approved by the FDA as a once-weekly weight loss shot under the name Wegovy for adults who were either obs ese or overweight with at least one weight-related condition, such as high blood pressure, type 2 diabetes, or high cholesterol. In December 2022 it was approved for those aged 12 and up with the same conditions.

Tirzepatide

Tirzepatide was approved by the FDA for adults with diabetes in May 2022, under the name Mounjaro.

Like semaglutide products, tirzepatide is used to control blood sugar levels, and is administered via a weekly injection. Unlike semaglutide, it mimics the GIP hormone as well as GLP-1.

People have been found to lose large amounts of weight on the drug in trials, but it is not approved by the FDA for this purpose.

In addition to the trial results released on April 27, a clinical trial published in the New England Journal of Medicine last year showed that patients who were obese or overweight and had other health conditions such as high blood pressure, high cholesterol, or cardiovascular disease lost 20% of their body weight in 16 months while taking the maximum dose of 15mg. That potentially makes it more powerful than semaglutide for weight loss.

Liraglutide

Novo Nordisk also manufactures liraglutide, which is marketed as Saxenda.

Saxenda was approved by the FDA in December 2014 for weight management for adults who are overweight or obese with a weight-related condition. In April 2020, the drug was approved for those aged 12 and over, too.

Its effects are less significant than other drugs, with people losing between 4 to 6 kilograms or 5 to 10% of their body weight, according to a 2017 review.

During a trial, one patient died by suicide so patients should also be monitored for depression and suicidal thoughts while taking it, according to the FDA.