Weight-loss peptide only approved for use in HIV patients

"One of my favorites: tesamorelin," said Joy Kong, a regenerative health physician, in a July 13, 2026 Facebook reel. "It helps preserve lean body mass and also increase muscle building, and all this at the same time it decreases your fat, especially belly fat that is the visceral fat."

Kong called the peptide a "hack" that "also promotes growth hormone production."

Similar posts have spread across platforms.

Image

Screenshot of a Facebook reel captured on July 27, 2026

Image

Screenshot of a Facebook post captured on July 27, 2026

Peptides are short chains of amino acids, the building blocks of proteins. They occur naturally in the body and play a role in regulating hormones, and several approved drugs are peptide-based, including insulin and newer GLP-1 medications like Ozempic.

Synthetic peptides are increasingly buzzy in the wellness industry as the key to an optimized life. Bodybuilders and health influencers have often promoted injectable versions on social media as a weight-loss and muscle-growth solution or to boost sleep and cognition.

The posts hawking tesamorelin exaggerate the benefits demonstrated by available research, however.

Tesamorelin stimulates the production of human growth hormone, which has been linked to improved sleep quality and cognition, muscle gain and fat reduction.

But while reducing deeply stored visceral fat is tesamorelin's primary use, it has been mainly tested on -- and only approved for -- HIV patients, who can gain excess fat tissue as a side effect of their treatment (archived here).

AFP contacted several of the influencers supporting such supplements, but did not receive an immediate response.

Limited research

Some of the social media posts pushing tesamorelin referenced a 2007 study in the New England Journal of Medicine that found visceral fat decreased by about 15 percent in HIV patients taking tesamorelin (archived here).

Visceral fat consists of fatty cells that envelope internal organs and are linked to heart disease, cholesterol problems and fatty liver. It differs from subcutaneous fat, the soft and pinchable tissue that sits just beneath the skin and influences body shape.

A separate 2019 study, also focused only on HIV patients, determined that tesamorelin can increase muscle area by stimulating the release of human growth hormone (archived here).

But Julian Falutz, an assistant professor at McGill University Health Centre in Montreal, Canada and one of the 2007 study's authors, told AFP that because visceral fat is so deep within the body, it is not likely to impact visible weight loss or muscle growth (archived here).

"Nobody's recommending this either for bodybuilders or for muscle increase or for a generalized sort of weight loss drug," Falutz said in a July 25 interview. 

Falutz said it is possible tesamorelin could decrease visceral fat in non-HIV patients, but the research remains limited. Most tesamorelin studies could not determine its long-term efficacy, side effects or clinical benefits, he added.

"It does biologically what it is supposed to do, but the consequences of that good biological effect have never been proven," Falutz said.

The US Food and Drug Administration has approved the original tesamorelin treatment, Egrifta, for use in HIV patients. But according to its label, it is "not indicated for weight loss management" (archived here).

The manufacturer withdrew its application for approval in Europe after the European Union's Committee for Medicinal Products for Human Use could not determine if its benefits outweighed the potential risks of approving the drug (archived here and here). 

Steven Grinspoon, director of Harvard University's Nutrition Obesity Research Center, said a smaller paper in non-HIV patients yielded similar results relating to fat loss and lean muscle mass, but he cautioned against off-label tesamorelin use without further research (archived here and here).

"Results in one population cannot necessarily be assumed in a different population," Grinspoon, who also worked on the 2007 study, told AFP in a July 27, 2026 email. 

He noted that in HIV patients, growth hormones can improve thymic activity -- the function and output of the Thymus gland. But he said he did not know of any assessments using tesamorelin specifically (archived here). 

Growth hormone therapy has been linked to improved sleep and cognition, but research on tesamorelin's effects remains limited (archived here and here).

Off-label trend

The drive for off-label tesamorelin use is part of a broader trend of peptide supporters promoting products for potential health benefits, usually on the basis of genuine but limited -- or exaggerated -- scientific evidence.

At a July 23 review panel to determine recommendations for certain peptides, Anant Vinjamoori, chief medical officer of the online medication provider "Hims," urged advisors to take seriously a different peptide treatment, despite what he called "thin" evidence.

AFP found several social media posts promoting peptides were affiliated with telehealth providers, online pharmacies or peptide clinics that sell these products.

Health professionals and influencers refer to this supply chain as a "gray market," in which sellers provide unapproved products through loopholes, including by adding warning labels such as "research purposes only" and "not for human consumption" (archived here).

Proponents of peptide approval, including US Health Secretary Robert F. Kennedy Jr., have argued that the restrictions incentivize Americans to buy from unsafe suppliers. Critics, on the other hand, say the lack of evidence means there are safety concerns if they enter the market before rigorous testing is completed.

Read more of AFP's reporting on health misinformation here.