A new meta-analysis comparing popular GLP-1 weight loss medications found that tirzepatide, sold under the brand names Zepbound and Mounjaro, produced greater weight loss than semaglutide or liraglutide. The findings point to a clear difference in how much weight patients can expect to lose depending on which drug they take.
According to Healthline, participants using tirzepatide lost 15 to 20 percent of their body weight. Those taking semaglutide, sold as Ozempic or Wegovy, lost around 12 to 13 percent. Liraglutide, sold as Saxenda, showed the lowest weight loss percentage, around 5 percent.
The review was conducted by researchers at the University of Georgia College of Pharmacy. "We were interested in finding which drug gives the most weight loss and doesn't have higher rates of side effects like nausea and gastrointestinal problems," said Pooja Gokhale, the corresponding author of the review and a doctoral student at the college. "Tirzepatide seems to be the better option," Gokhale said.
GLP-1 medications work by mimicking natural hormones in the gut, which help to lower blood sugar, slow digestion, and promote feelings of fullness to aid weight loss. Semaglutide and liraglutide target GLP-1 receptors only. Tirzepatide targets both GLP-1 receptors and a second gut hormone called GIP. Researchers believe this dual mechanism may explain why tirzepatide produces greater weight loss results.
The drugs also differ in how long they stay active in the body. Liraglutide has a half-life of only around 13 hours and requires a daily injection. Semaglutide and tirzepatide have half-lives of one week and five days, respectively, allowing both to be taken with weekly injections. Researchers noted that how the body processes each medication may also play a role in weight loss outcomes.
Not everyone involved in weight management research believes tirzepatide is the clear winner for all patients. Clare Thompson, a general practitioner and weight management services lead at Cadogan Clinic in the United Kingdom, was not involved in the study but offered perspective on the findings. "While tirzepatide may achieve greater average weight loss, there is no single 'best' medication for every patient," Thompson said.
Thompson also pointed to the longer track record of semaglutide as a factor worth considering. "Semaglutide has been on the market for longer and subsequently has more robust, long-term data on outcomes for reducing heart attacks and strokes, and also good evidence to support a reduction in renal disease," she said. Cost may also be a deciding factor, as semaglutide is often less expensive than tirzepatide.
Semaglutide is also available in an oral pill form, sold as Rybelsus, which may be preferable for patients who want to avoid injections. Thompson noted that future research will be needed to determine whether the additional weight loss seen with tirzepatide translates into better long-term health outcomes compared to other GLP-1 therapies.
