Buzzy GLP-1 Drug Retatrutide Led to Dramatic Weight Loss in Diabetes Trial

Last summer, drugmaker Eli Lilly shared highlights of clinical trial results for its highly anticipated medication retatrutide, nicknamed “reta.” Now, scientists have published the findings in a peer-reviewed medical journal, allowing healthcare providers and potential patients to learn more details about what the research discovered.

“These are impressive results, and what makes them notable is the population,” says Gitanjali Srivastava, MD, an obesity medicine specialist and medical director of Vanderbilt Obesity Medicine in Nashville, Tennessee. “People with type 2 diabetes have historically lost less weight on obesity medications than people without diabetes.”

What Is Retatrutide?

Retatrutide is not the same as other medications in the GLP-1 space like semaglutide (Wegovy, Ozempic) and tirzepatide (Zepbound, Mounjaro). It is a triple-agonist (“triple G”) medication that acts on three different hormone receptors in the body — glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP), and glucagon (GCG).

Tirzepatide works on two receptors (GLP-1 and GIP); semaglutide works on one receptor (GLP-1).

Retatrutide is experimental and not yet approved by the U.S. Food and Drug Administration (FDA) for use by the general public. The latest clinical trial results, however, put the medication one step closer to an FDA okay.

Adults With Type 2 Diabetes Saw Significant Changes in Blood Sugar and Weight

The trial results, which were published in The Lancet, followed close to 1,200 participants with type 2 diabetes and overweight or obesity who were randomly assigned to take weekly doses of retatrutide at 4, 9, or 12 milligrams (mg) or a placebo (dummy medication).

After 80 weeks, participants on retatrutide had impressive weight loss results:

At the 12 milligram dose, almost half of participants lost 20 percent of their starting weight, while about 30 percent lost at least 25 percent of their starting weight.

For comparison, people who used a placebo lost 5.1 percent of their starting weight.

Participants also saw changes to their A1C levels, a measurement that estimates average blood sugar levels over the previous two to three months:

Participants who took a placebo saw their A1C drop by 0.45 percent.

“The drug treats the disease that drives the diabetes and the diabetes itself,” Dr. Srivastava says.

People Are Buying Bootleg Retatrutide Online, But Experts Say 'Don't Do It'

The buzz around retatrutide has contributed to a thriving gray market serving people looking for serious weight loss who aren’t interested in waiting for the FDA to approve the drug. They are going online to buy medications marketed as reta from websites hawking bootleg versions labeled “for research purposes.”

This has led to concerns in the medical community. “The clinical trial results are really promising, so I completely understand why people are interested, but what’s being sold online isn’t necessarily the same product that’s being studied in clinical trials,” says Christine Bonarrigo, PharmD, a weight management pharmacist at Tufts Medical Center in Boston. “There’s a big difference between participating in a clinical trial and buying an unregulated vial off the internet.”

“Don’t do it,” Srivastava says. “Anything sold online right now is not a regulated pharmaceutical product.” As a result, she points out that there’s no way to know what’s actually in the vial, whether the dosing on the label is accurate, and even if the product is sterile.

“This is also a potent drug with real side effects, including drops in blood pressure, that should be monitored by a clinician,” Srivastava says.

FDA-approved, effective obesity medications are available — Srivastava recommends speaking to your healthcare provider about those “instead of taking a gamble with your health.”

Who Might Benefit Most From Retatrutide

Retatrutide may provide the most benefit to a particular subset of people.

“If it’s approved, I expect it to be especially valuable for people with obesity who need substantial weight loss to improve serious complications, like type 2 diabetes, fatty liver disease, sleep apnea, or joint disease, and for people who haven’t responded well enough to current medications,” Srivastava says.

The medication may also be helpful for people who aren’t candidates for bariatric surgery or who prefer a drug treatment to surgery, Dr. Bonarrigo says. “Retatrutide appears to push the field closer to achieving those larger, clinically meaningful weight loss targets with medication alone,” she says.

Larger, sustained weight loss efforts above losing 10 percent of body weight are often what lead to diabetes remission and meaningful improvements in blood pressure, liver health, and mobility, Srivastava says.

But she stresses that not everyone needs the most powerful drug. “Obesity treatment should be individualized, and having more tools lets us match the medication to the patient,” she says.