Does Tesamorelin Build Muscle in People With HIV?

A man in your walking group has HIV and has started tesamorelin, sold as Egrifta, to shrink the deep belly fat his doctor spotted on a scan. Gym forums told him the same medicine also “builds muscle,” and he wonders whether he can skip the strength class. Does tesamorelin build muscle in people with HIV?

Not in any way that has been shown to matter in daily life. CT scans from two earlier tesamorelin trials, reanalyzed years later, found slightly larger trunk muscles with less fat inside them after six months, but only among people whose belly fat had already responded. The gains were small, about half a square centimeter to one square centimeter on a single scan slice, and no one measured strength, walking or falls. A trial now under way is testing tesamorelin on top of exercise, not instead of it.

What the CT scans measured

Tesamorelin is a lab-made version of growth hormone-releasing hormone, approved in the United States to reduce excess abdominal fat in adults with HIV. In 2019, a team led by Adrian and Erlandson went back to CT images from two completed placebo-controlled trials. They compared 193 people whose deep belly fat fell by at least 8 percent on tesamorelin with 148 people on placebo, most of them white men, over 26 weeks.

Four trunk muscle groups, including the abdominal wall and the psoas muscle near the spine, became denser on tesamorelin, which on CT usually means less fat mixed into the muscle. The lean area of those muscles grew by roughly 0.6 to 1.1 square centimeters more than on placebo. The authors called the work exploratory and wrote that the effect of these changes on daily life still needs study.

A companion 2021 analysis of the same participants, led by Lake, found that tesamorelin also made the remaining belly fat and fat under the skin denser on CT. The researchers read that as a sign of healthier fat cells, separate from the drop in fat amount. Both papers studied responders only, about seven in 10 people who took the drug, so they describe what happened when the medicine was already working.

What these studies cannot tell you

A CT number is not a stronger grip, a faster walk or fewer falls. The analyses did not test any of those, did not include people without HIV, and lasted six months. Leaving out people whose belly fat did not shrink makes the drug look better than it would for everyone who starts it. Several authors of the 2021 paper reported ties to drug companies, including consulting for the maker of tesamorelin. Research products sold online under the name TESA were not tested in these trials, which used the approved medicine under medical supervision.

What to do while an exercise trial runs

The TRIUMPH trial, which began recruiting in 2025, is enrolling about 100 sedentary adults aged 50 to 80 with HIV who are frail or at risk of frailty and carry extra belly fat. Everyone follows a home-based, partly supervised exercise program for 24 weeks, with tesamorelin or a placebo added, then exercises on their own for another 24 weeks. Its main questions are physical function, muscle quality and quality of life. Until it reports, regular strength and walking exercise remain the standard advice for keeping muscle.

For your walking partner, that means keeping the strength class. Tesamorelin has evidence for reducing deep belly fat in HIV, and these scans hint at a small side benefit for trunk muscle, but no study has shown that it replaces exercise. If staying strong is his goal, he can ask his HIV clinician about a physical therapy referral, whether TRIUMPH or a similar trial is near him, and how the medicine fits with his other treatment. Not medical advice.

More Muscle on Tesamorelin? What CT Scans in HIV Trials Measured

What the CT scans measured

What these studies cannot tell you

What to do while an exercise trial runs

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