Eli Lilly and Company announced in December that its next-generation weight loss drug retatrutide helped patients shed more pounds than any other similar weight-loss drug during a late-stage trial.
Patients taking the once-weekly drug over the course of 68 weeks lost nearly 29 percent of their body weight, whereas patients taking semaglutide drugs such as Ozempic or Wegovy previously lost only 16 percent.
But retatrutide functions differently than other popular drugs.
That’s because it’s a triple hormone receptor agonist. Instead of targeting and stimulating just one hormone to help curb appetite and make people feel fuller like GLP- class drugs, retatrutide targets three.
Now, some people are calling retatrutide a “GLP-3.”
What is a GLP-3 and how does it work?
Semaglutide weight loss drugs work by mimicking the hormone GLP-1, which is also known as Glucagon-Like Peptide, according to the Cleveland Clinic. The drugs do this by activating the proteins in the brain that produce the hormone.
GLP-1 helps to regulate blood sugar and reduce appetite, as well as slow digestion.
Retatrutide works by mimicking three different hormones: GLP-1, GIP and Glucagon.
GIP, or Glucose-Dependent Insulinotropic Polypeptide, works harmoniously with GLP-1 to improve the body’s metabolism and our release of blood sugar-regulating hormone insulin
Glucagon helps the body burn stored fat for fuel and reduces body weight.
Eli Lilly’s competitor Novo Nordisk announced a license agreement for a GLP-3 drug in March of last year.
Eli Lilly’s Mounjaro is the only dual drug on the market, targeting GLP-1 and GIP. Doctors say that Mounjaro is also more effective than semaglutide drugs, although results show less weight loss over 72 weeks.
Risk and reward
Experts believe the combination of all three hormones is why GLP-3 drugs could prove to be more effective going forward.
However, more research needs to be conducted into their safety – and they are not without risk.
More than 12 percent of patients in the retatrutide drug trial lost so much weight and experienced other “adverse events” that they stopped taking the drug, Eli Lilly said.
And, more than 20 percent of people taking the highest dose of the Eli Lilly drug – 12 milligrams – also had a condition that makes touching the skin painful.
Still, the majority of side effects were consistent with those felt when taking weight loss drugs currently on the market, such as nausea, diarrhea, vomiting and constipation.
One in eight Americans are taking a GLP-1 drug, according to a recent KFF Health Tracking Poll.
