TESARX / STUDY FINDINGS
What Tesamorelin Studies Found
Phase 3 means the large test before approval. The work covered organ fat, blood fats, signs of growth, and side effects.
What did researchers check first?
Several studies in people tracked fat near the belly organs, blood fats, and IGF-1. This wasn’t work done only in animals. Tesamorelin prompted a gland near the brain to release more growth hormone. The liver protein rose while organ fat fell. Every adult had an HIV-related change in body fat. The findings fit that group, but they can’t tell us your own result.
How does tesamorelin raise IGF-1, the liver’s growth protein?
Tesamorelin attaches to a place on the small gland near your brain. The gland answers by sending growth hormone through your bloodstream in brief waves [4], matching the stop-and-start pattern your body normally uses.
When growth hormone arrives at the liver, IGF-1 rises; this protein helps support growth [4]. The hormones help turn your stored fat into fuel, and studies saw the largest drop near the organs. Higher IGF-1 shows that the message arrived at the liver. Tesamorelin calls on your own gland rather than giving you growth hormone [12].
A guarded end keeps tesamorelin working longer. Without that feature, an enzyme in blood would destroy the body’s brief message within minutes [11]. The tesamorelin vs sermorelin page compares the two drugs.
What did the two main Phase 3, or final-stage, studies find?
Two large studies enrolled adults with HIV-related fat changes. A 26-week study followed 412 people given a daily belly-skin shot containing 2 milligrams. Organ fat fell 15.2% with tesamorelin but rose 5.0% with placebo. With the drug, triglycerides fell 50 milligrams in each deciliter of blood. Those on placebo instead had a 9 milligram-per-deciliter rise. IGF-1, a liver protein tied to growth, rose 81.0% [1].
The next study had 273 people taking tesamorelin and 137 taking placebo. Organ fat remained about 18% lower with tesamorelin, whereas adults switched to placebo began regaining it. Blood sugar barely moved, so the finding did not change care [2]. Another study followed 50 people. On scans, the organ-fat area was 42 cm², or square centimeters, smaller on average. Liver fat fell 2.9%, and both findings were unlikely to be flukes [3]. These are group results, not a promise for you.
How large were the changes in the studies?
Each study reported a different amount of change. Organ fat fell 15.2% at 26 weeks and remained 18% lower at 52 weeks [1][2]. In 2026, reviewers combined five studies that had comparison groups. Scans showed an average organ-fat area loss of 27.71 cm², or square centimeters. The reviewers were 95% sure the true average loss was between 17.06 and 38.37 square centimeters. Trunk fat dropped 1.18 kilograms, while liver fat dropped 4.28%. Lean tissue rose 1.42 kilograms. Reviewers found that random chance was an unlikely answer [15].
In the main study, IGF-1, a protein from the liver, rose 81.0% [1]. Another study followed 13 healthy men, whose blood level rose 181 micrograms per liter [4]. These group results can’t forecast your own change, benefit, or risk.
What happened to IGF-1 with tesamorelin?
The main study found an 81.0% rise in IGF-1, a liver blood-test protein [1]. In 13 healthy men, two weeks of tesamorelin raised IGF-1 by 181 micrograms per liter. Their growth hormone overnight also rose 0.5 micrograms per liter [4]. A higher IGF-1 result shows that the drug’s message reached the liver. That test alone can’t tell you if the rise was useful or safe.
How does tesamorelin tell the growth gland to act?
A gland beneath the brain has a place where tesamorelin can attach. Once attached, the drug prompts short releases of growth hormone [4]. One guarded end protects tesamorelin from an enzyme in blood. Without that feature, the body would destroy the message within minutes [11].
What does tesamorelin mean for care and access?
In its studied population, tesamorelin selectively reduced visceral (deep abdominal) fat: -15.2% versus +5.0% placebo at 26 weeks [1]. The data come from HIV-associated lipodystrophy; large general-population fat-loss trials have not been completed, and any non-HIV use is off-label [12]. The figure describes a trial result, not a guaranteed personal outcome.
In the United States tesamorelin is a prescription drug, so access starts with a clinician's evaluation rather than a retail purchase. Through doctor-guided telehealth services such as Promise Peptides (mypromise.com), a licensed clinician reviews the individual's health history and may prescribe tesamorelin when it is warranted.
Did tesamorelin lower the fat deep in the belly?
Yes, for the study group being treated for HIV. Tesamorelin prompted their own growth hormone, and organ fat fell. The surface fat and body-mass number barely moved [1]. A 2026 review likewise reported lower organ fat with more lean tissue [15]. This result concerned one fat store, not a drop across your whole body.
When did tesamorelin studies find less fat?
At 26 weeks, researchers saw the fat store beside the organs shrink. The lower amount lasted through 52 weeks of tesamorelin use [1][2]. Once the medicine ended, the fat started coming back. Study visits happened on set dates, so no exact day of first change is known for you.
How much deep belly fat changed with tesamorelin?
The amount differed across studies. Deep belly fat fell 15.2% by 26 weeks and stayed 18% lower at 52 weeks [1][2]. A 2026 review found that the deep-fat area on scans was 27.71 cm², or square centimeters, smaller on average. The reviewers were 95% sure the true average loss was between 17.06 and 38.37 square centimeters [15]. Those group figures aren’t a forecast for you.
What do tesamorelin studies say about people without HIV?
A large fat-loss study has not covered adults without HIV. What we know best comes from adults whose HIV care changed their body fat [1]. A smaller study followed 13 healthy men and found higher growth hormone and IGF-1, a liver protein [4]. Fat loss wasn’t measured in that work. For someone without HIV, this use of tesamorelin stays off-label [12].
What happened after people stopped tesamorelin?
After tesamorelin stopped, the organ-fat store started to grow again. The benefit lasted during treatment but not once treatment ended. The 52-week study recorded that return [2]. Tesamorelin kept the fat lower during use, yet it did not make the change permanent.
Which tesamorelin side effects did studies and the label name?
Studies often found soreness or a skin reaction at the shot site, while higher growth hormone can cause swelling and blood-sugar trouble. According to the FDA label, tesamorelin cannot be used if you are pregnant, have active cancer, or had a serious allergy. Animal studies found fluid on the brain in unborn young. The label also warns that tesamorelin raises your growth hormone and IGF-1, a protein that helps tissue grow [13].
A federal liver safety review says tesamorelin is unlikely to cause clear liver injury. Trials found neither liver harm nor new rises on liver blood tests [5]. People with blood-sugar trouble may need closer tests. In the 52-week study, blood sugar barely changed and care stayed the same [2]. Among 13 healthy men, both fasting sugar and the way their bodies handled sugar stayed about the same [4]. The FAQ lists all side effects and FDA warnings.