The latest class of weight-loss medications have been game-changing for the treatment for obesity and related conditions such as diabetes, and more are on the way, pending additional research and FDA approval.
With new research emerging regularly, it can be difficult to keep track of all the options.
Here are the major weight-loss medications currently being used and studied, how they work, and the latest research and news on their effectiveness and side effects.
Semaglutide (sold as Ozempic, Wegovy)
Background: Semaglutide, a once-weekly injection first designed to treat diabetes, was one of the first medications of its type to be a called a "game changer" for weight loss. It was FDA approved for that purpose in 2021, and is sold by Danish pharmaceutical giant Novo Nordisk.
The drugmaker is also developing a once-daily pill version of semaglutide, with early evidence suggesting it could be just as effective as injections.
How it works: It mimics a naturally occuring hormone called GLP-1, which helps regulate appetite and digestion. As a result, patients notice reduced cravings, especially for highly-palatable foods like sugary treats or rich, fatty meals.
Effectiveness in clinical trials: Clinical trials found that patients taking semaglutide lost an average of 15% of their body weight over 68 weeks. However, research suggests people need to continue taking the drug to maintain the weight loss.
Emerging evidence suggests that semaglutide may also help reduce the risk of heart attack and stroke. One study found it may help prevent colon cancer, too.
Side effects: Common side effects of the medication include nausea, diarrhea, vomiting, and constipation.
Why you've heard of it: Semaglutide has received a major popularity boost thanks to mentions from celebrities like Elon Musk. Due to social media trends, Ozempic has become one of the most recognizable terms for weight loss medication, although that brand name is marketed for diabetes.
Popular terms such as "Ozempic face" refer to the brand while describing side effects, in this case sagging skin related to rapid weight loss.
Semaglutide has also been controversial because of widespread shortages beginning soon after it was approved for weight loss. The high demand prompted a wave of "copycat" versions of the drug, known as compounded semaglutide.
Cost: About $936 for Ozempic and $1,349 for Wegovy per month. Insurance coverage can be complicated, making the drug out of reach for many who could benefit from it.
Tirzepatide (sold as Mounjaro, Zepbound)
Background: Tirzepatide is a newer medication, initially earning FDA approval as a diabetes treatment in 2022 under the brand name Mounjaro from pharmaceutical company Eli Lilly.
Lilly's version specifically prescribed for weight control, branded Zepbound, received FDA approval in early November 2023.
How it works: Tirzepatide acts on GLP-1, like semaglutide, but also works on another hormone called GIP, which could boost the effects on appetite and weight loss, obesity medicine doctors previously told Insider.
Effectiveness in clinical trials: Available evidence suggest it may be even more effective than semaglutide at helping patients shed pounds. An early study found people taking the medication lost 20% of their body weight, an average of 52 pounds, in in about 16-months.
A clinical trial found that nearly half of overweight, diabetic patients taking the drug lost at least 15% of their body weight, a "landmark" result, according to the study's lead author.
A recent study also found that people who stop taking tirzepatide will regain at least some fo the weight they lost on the medication.
Side effects: Tirzepatide has similar side effects as semaglutide, including gastrointestinal issues, but they may be less severe, mitigated by the drug's effect on both hormones.
Why you've heard of it: Like semaglutide, tirzepatide has made a name for itself in the media with dramatic weight-loss stories and social media trends, as well as concerns from patients about accessing the drug long-term.
Cost: $1,023 per month for Mounjaro, $1,059.87 for Zepbound
Liraglutide (sold as Victroza and Saxenda)
Background: Liraglutide, also sold by Novo Nordisk, has been available the longer than comparable GLP-1 medications, approved in 2010 for diabetes and in 2014 for weight loss.
How it works: It is less long-lasting than newer drugs, and therefore needs to be adminsitered as a once-daily injection instead of once-weekly.
Effectiveness in clinical trials: Research suggests patients lost about 5 to 10% of their body weight, according to one review.
Side effects: While liraglutide has similar gastrointestinal side effects as other GLP-1 drugs, it's also been linked to more concerning reactions, such as pancreatitis, gallbladder disease and in rare cases, mental health symptoms such as worsening depression or insomnia.
Cost: About $1,349 per month for Saxenda
Retatrutide: the newest medication pending FDA approval
Background: Retatrutide is the newest contender in once-weekly injectable GLP-1 medications, currently slated for phase 3 trials, from pharmaceutical company Eli Lilly.
How it works: It's earned the nickname "triple G" because it works on three different hormonal pathways. Similarly to semaglutide, reatrutide acts on GLP-1, and like tirzepatide, it acts on GIP. However, it adds yet another interaction to the mix by targeting receptors for another hormone called glucagon, which influences blood sugar.
Effectiveness in clinical trials: The most recent evidence, published June 26 in The New England Journal of Medicine, showed that patients taking the highest dose of the medication once a week lost 24.2% of their body weight in 48 weeks, results comparable to those seen with bariatric surgery.
Side effects: Research is still underway to understand possible side effects of retatrutide. Available evidence suggests any issues are mostly gastrointestinal, and can be managed by starting with a lower dose and gradually increasing, similar to other GLP-1 drugs.
Cost: TBD
