What to Know About the ‘Reta’ Injection Trending Online

If you’ve spent any time in fitness or weight-loss corners of social media lately, chances are you’ve seen the term “reta” pop up. Sometimes it’s tucked into a caption about leaning out; other times, it appears casually in comment threads alongside gym selfies and dramatic before-and-after photos. To the untrained eye, retatrutide can start to look like the next GLP-1 alternative already circulating in real life.

But behind the buzz is a very different reality. Retatrutide is not FDA-approved. It is not commercially available. And while obesity medicine specialists have been watching its development closely for years, many are increasingly uneasy about how casually it’s being discussed—and, in some cases, used.

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Featured Experts

• Eduardo Grunvald, MD is a board-certified internist and obesity medicine specialist in San Diego, CA
• Judith Korner, MD is a board-certified endocrinologist in New York
• Raoul Manalac, MD is the senior director of obesity science at Ro

What Is Retatrutide?

Retatrutide is an investigational weight-loss medication from Eli Lilly and is widely viewed as the next generation of GLP-1 therapies, following semaglutide and tirzepatide. While semaglutide targets one hormone pathway and tirzepatide targets two, retatrutide goes a step further. It works on GLP-1 and GIP, plus an additional glucagon pathway, which is why some people have started referring to it as a “GLP-3.” That third mechanism is what researchers believe could drive greater weight loss than current medications, though the drug is still being studied and is not FDA-approved.

That potential is what has driven both medical interest and online speculation. Early and later-stage trials have shown striking weight loss, with some studies suggesting average losses approaching 30 percent of body weight in people with obesity. Those results help explain why retatrutide is already being discussed as a next-generation option—even as it remains investigational and FDA approval has not yet happened.

Why It’s Trending

Despite not being approved, retatrutide has become a frequent topic among weightlifters, fitness influencers and online weight-loss forums. On TikTok, where searches for #reta and #retatrutide are restricted, the drug often appears under a coded nickname: “ratatouille.”

According to San Diego internist and obesity specialist Eduardo Grunvald, MD, most of what’s circulating is not coming through legitimate channels. “As far as I’m aware, from compounding pharmacies and clinics, likely overseas sources for the chemical compound,” he says.

That distinction matters. Any product being sold as retatrutide outside of a clinical trial is unregulated and unverified, he tells us.

Why Doctors Are Concerned

“Phase 3 studies have not yet been completed, so we do not know the full safety profile yet,” says Dr. Grunvald. “Use outside of clinical trials is extremely irresponsible.”

New York endocrinologist Judith Korner, MD, is even more direct. “No one should be taking retatrutide until it is FDA-approved and available from the pharmaceutical company authorized to produce it,” she says. “Any product being sold as retatrutide is counterfeit.”

Why It’s Not Intended for Recreational Use

Experts say retatrutide is being studied for people with obesity or overweight and related medical conditions, not cosmetic leaning or performance-driven goals. That context is important, especially as online conversations move faster than science.

“If these results are replicated in future studies, retatrutide has the potential to provide greater weight loss benefits than any GLP-1 medication currently on the market,” says Raoul Manalac, MD, senior director of obesity science at Ro. “But it’s not clear yet if and when the drug is about to hit the market.”

That uncertainty is why specialists urge patience. These medications are meant to be part of a structured medical plan, not a shortcut layered into an aggressive fitness routine. Using them without medical supervision carries real risks and can undermine both safety and long-term outcomes.

For now, doctors say “reta” is still in the research phase, and what’s circulating online isn’t the same medication being studied in clinical trials or something patients should be using yet. Until that changes, experts say the safest—and smartest—move is to stay out of the comments and wait for the science to catch up.