What is this medicine?
Tesamorelin: What Can It Do, and Who Was Studied?
Tesamorelin prompts a natural hormone rise. Here is what changed in adults with HIV and what the studies can't yet answer.
What is tesamorelin meant to do?
Tesamorelin is a daily shot that prompts the growth gland to send more hormone into the blood. That hormone tells the liver to make a protein, and both help the body use stored belly fat.
The main studies found about 15% less fat deep around the organs. That isn't the same as losing weight all over.
The FDA approved tesamorelin for just 1 use tied to HIV. Any other use is off-label, meaning the FDA hasn't approved it.
What did the tesamorelin studies prove?
The medicine is built from protein parts and copies a brain message that tells the growth gland to work [1]. An added part slows early breakdown, which helps the shot keep working after it enters the blood.
The large late-stage study, called Phase 3, included 412 adults with HIV. Those given 2 milligrams a day lost more deep belly fat than those given a sugar pill.
The same study found a drop of 50 milligrams per deciliter in a blood fat [1]. One liver-made growth protein also rose, as the medicine was meant to make it do.
A longer study found 18% less deep belly fat after 52 weeks [2]. The change lasted only while people kept taking the medicine.
In 2026, reviewers combined five fair tests [12]. They found less deep fat and liver fat, along with more weight from muscle and other lean tissue.
That review found no serious side effects. Still, the results don't prove fat loss for all adults.
Tesamorelin has only 1 approved use, and the main studies followed adults with HIV. That 1 approved use doesn't cover everyone, and the fat returned after treatment stopped [2].
The complete source list matches each bracketed number to a paper. The deep belly fat page gives results, while the research page explains the body changes.
Why is tesamorelin called a peptide?
A peptide is a short chain made from protein parts, and tesamorelin has 44 protein parts [1]. Their order copies a brain message that tells the growth gland below the brain to release growth hormone.
Tesamorelin has one added part that slows early breakdown [1][7]. The added part lets the medicine prompt a hormone rise after the shot.
The shot causes the body to release its own growth hormone. Tesamorelin doesn't add growth hormone from outside the body.
The tesamorelin vs sermorelin page compares it with a shorter medicine. The difference concerns their make-up and the amount of human study behind each one.
How does tesamorelin raise 1 key growth protein?
Step 1 begins when tesamorelin attaches to growth-gland cells, which then send the body's own growth hormone into the blood [1]. In 1 later step, the liver makes 1 protein that joins the hormone in helping the body use stored belly fat [1].
A growth-hormone shot puts the hormone straight into the blood. Tesamorelin acts sooner in the process, so normal rises and falls remain [1].
For two weeks, healthy men received 2 milligrams a day. The liver-made protein rose by 181 micrograms per liter, while blood sugar control stayed steady [4].
Those findings describe the men as a group, not a sure result for you. The research page explains each body step and the limits of the study.
Is Tesamorelin a Steroid, or Is It Growth Hormone?
Tesamorelin is neither a steroid nor growth hormone. A steroid has a different make-up and does a different job.
Tesamorelin copies a message from the brain. The growth gland answers with timed bursts of growth hormone made inside the body [1].
A growth-hormone shot puts that hormone straight into the blood. Tesamorelin prompts an inner release, so the body's normal checks still work [4].
Healthy men had less deep belly fat without worse blood sugar control [4]. That finding doesn't prove the same result for you.
What use of Tesamorelin has the FDA approved?
The FDA has approved tesamorelin for one narrow use. In 2010, the United States approved the medicine for that use [5].
It is for adults with HIV who have too much deep belly fat. Doctors call this lipodystrophy, meaning HIV or its drugs changed where fat sits.
No other use has FDA approval [5]. Use for looks, aging, sports, or fatty liver remains off-label.
Tesamorelin sold only for lab work isn't the approved medicine for people. Competing athletes also need to know that sports rules ban it.
The approval page gives the exact limit, and the FAQ names who must avoid it. You can read both before speaking with your doctor.