Tesamorelin is a synthetic hormone that signals your pituitary gland to release more growth hormone. It’s FDA-approved as a daily injection (sold under the brand name Egrifta) specifically to reduce excess belly fat in people with HIV who have developed a condition called lipodystrophy, where fat accumulates abnormally around the midsection. Beyond that primary use, research suggests it may also reduce liver fat and slow liver scarring in this population.
How Tesamorelin Works in the Body
Your brain naturally produces a signaling molecule called growth hormone-releasing hormone (GHRH), which tells the pituitary gland at the base of your brain to pump out growth hormone. Tesamorelin is a lab-made version of that same molecule, modified slightly to last longer in the body. When injected, it binds to the same receptors on the pituitary gland and triggers a natural pulse of growth hormone release.
That extra growth hormone then sets off a chain of metabolic effects. It promotes the breakdown of stored fat (particularly the deep visceral fat packed around organs in the abdomen), increases lean muscle tissue, and raises levels of a downstream hormone called IGF-1, which mediates many of growth hormone’s effects throughout the body. Because tesamorelin works through your own pituitary gland rather than injecting growth hormone directly, the body retains some of its normal feedback mechanisms, which helps keep growth hormone levels from spiking dangerously high.
What It’s Prescribed For
Tesamorelin’s sole FDA-approved use is reducing excess visceral abdominal fat in adults with HIV-associated lipodystrophy. This condition is a well-known side effect of certain HIV treatments: fat redistributes away from the face and limbs and accumulates deep in the abdomen, raising the risk of heart disease and metabolic problems. The fat buildup isn’t just cosmetic. Visceral fat is metabolically active, driving inflammation and insulin resistance in ways that subcutaneous fat (the kind just under the skin) does not.
Clinical trials have shown tesamorelin meaningfully reduces this visceral fat compared to placebo. The drug is not approved for general weight loss, bodybuilding, or anti-aging purposes, though off-label interest in those areas exists.
Effects on Liver Fat
One of the more promising findings involves tesamorelin’s impact on fatty liver disease, which is common in people living with HIV. In a randomized, placebo-controlled trial published in The Lancet HIV, 12 months of tesamorelin reduced liver fat by 37% relative to baseline, compared to placebo. More strikingly, 35% of people on tesamorelin saw their liver fat drop below the 5% threshold that defines fatty liver disease, versus just 4% on placebo.
Tesamorelin also appeared to slow the progression of liver scarring (fibrosis). Only about 10% of people in the treatment group showed worsening fibrosis over the study period, compared to nearly 38% in the placebo group. However, it did not reverse fibrosis that was already present, and it didn’t significantly improve inflammation scores within the liver itself. For people who started the trial with elevated liver enzymes, tesamorelin did bring those levels down significantly, and it also lowered C-reactive protein, a marker of systemic inflammation.
Effects on Muscle Composition
Because growth hormone promotes both fat breakdown and protein synthesis, tesamorelin doesn’t just reduce belly fat. Research published in The Journal of Frailty & Aging found that it decreases fat stored within muscle tissue and increases overall muscle area in adults with HIV. This matters because fat infiltration in muscle is linked to weakness, insulin resistance, and reduced physical function, problems that become more pressing as people with HIV age on long-term antiretroviral therapy.
How It’s Taken
Tesamorelin is a once-daily subcutaneous injection given in the abdomen. The standard dose is 1.28 mg. It comes as a powder that you mix with a liquid diluent before injecting. You rotate injection sites around the abdomen each day, avoiding scar tissue, bruises, and the navel. Most people self-administer at home after initial training from a healthcare provider.
The treatment is ongoing. If you stop taking tesamorelin, the visceral fat typically returns, which means it manages the condition rather than curing it.
Monitoring During Treatment
Because tesamorelin raises growth hormone and IGF-1 levels, periodic blood tests to check IGF-1 are part of the treatment protocol. IGF-1 is a growth factor, and persistently high levels could theoretically promote the growth of existing tumors or other abnormal tissue. If IGF-1 climbs too high (generally more than three standard deviations above normal) and the drug isn’t producing a strong benefit, discontinuation is recommended.
Blood sugar levels also warrant attention. Growth hormone can reduce insulin sensitivity, so people with diabetes or prediabetes need closer monitoring while on tesamorelin.
Who Should Not Take It
Tesamorelin is contraindicated in anyone with an active cancer diagnosis, whether newly found or recurring. Because the drug increases growth hormone and IGF-1, both of which are growth factors, it could theoretically accelerate tumor growth. For people with a history of cancer that has been treated and is stable, the decision to use tesamorelin requires careful weighing of benefits against the risk of reactivating the malignancy. The same caution applies to non-cancerous growths.
It is also contraindicated during pregnancy. In animal studies, tesamorelin caused a serious brain abnormality (hydrocephalus) in offspring at doses comparable to the human clinical dose. Since visceral fat naturally increases during pregnancy as part of normal hormonal changes, there is no benefit to using tesamorelin during that time and clear potential for harm.
Common Side Effects
The most frequently reported side effects are injection-site reactions: redness, swelling, itching, or pain at the spot where the needle goes in. Joint pain and muscle aches also occur, which makes sense given the increase in growth hormone activity. Some people experience numbness or tingling in the hands, a symptom associated with fluid retention that growth hormone can cause. Swelling in the extremities is another possibility. These side effects are generally mild and tend to be most noticeable in the first weeks of treatment.