Peptide Injections: What They Are, What They Promise ...

“Injectable peptide medications themselves aren’t new,” Sogol Ash notes.

Well-known examples of injectable peptides include insulin, for managing diabetes, and GLP-1 (glucagon-like peptide-1) agonists, the class of injectable weight loss drugs like Ozempic, Wegovy, Mounjaro, and Zepbound, for treating diabetes and obesity.

Compounded GLP-1s for weight loss, such as compounded semaglutide and compounded tirzepatide, boomed in popularity over the past few years during shortages of name-brand GLP-1s.

Compounded drugs are off-brand formulations custom-made by a pharmacist or physician. They are generally less expensive than name-brand drugs, but they’re not approved by the FDA, which means the agency has not reviewed them for safety, efficacy, and quality. The FDA notes that compounded GLP-1s may pose risks.

What Is the Experimental GLP-1 Drug Retatrutide?

Retatrutide is an experimental compounded GLP-1 medication currently undergoing clinical trials. Preliminary data suggests that retatrutide could lead to more weight loss than semaglutide or tirzepatide because it targets more receptors involved in suppressing appetite and lowering blood sugar.

Buzz about these potential benefits is sending people online to buy “reta.”

The FDA, however, has not approved retatrutide, nor have large-scale studies proven it to be safe and effective, which experts say makes this a gray market product. “Retatrutide is not through phase 3 trials and not FDA-approved, so the [medication] source would be suspect and without safety data,” says Dr. Nadolsky.