Tesamorelin
Also known as: TH9507, Tesamorelin acetate, Egrifta, Egrifta SV, Egrifta WR
5 notable studies · 7 references
TLDR
Tesamorelin is an FDA-approved GHRH analogue with strong randomized human evidence for reducing excess visceral abdominal fat in adults with HIV-associated lipodystrophy, while research into liver fat, metabolic disease, inflammation, and other applications remains outside its approved indication.
Research Supports
- FDA-approved for reducing visceral abdominal fat in adults with HIV-associated lipodystrophy
- Investigated for effects on liver fat and metabolic dysfunction-associated steatotic liver disease
- Examined for changes in inflammatory and immune biomarkers associated with visceral adiposity
- Studied for neurocognitive effects in people with HIV and abdominal obesity
Observations Reported in Research
- Reduced visceral adipose tissue by roughly 15% relative to placebo across pivotal Phase 3 trials (Falutz et al., 2007; pooled analysis)
- Reduced hepatic fat fraction, with about 35% of treated participants reaching under 5% hepatic fat vs 4% on placebo (Fourman et al., 2019)
- Visceral fat reaccumulated rapidly after treatment was stopped (2010 safety-extension trial)
- Reduced waist circumference but did not significantly improve neurocognitive performance (2025 trial)
These are brief summaries of what the referenced research examined or reported — not conclusions about safety or effectiveness, and not medical advice. See Notable Studies and Sources & References below for the full context and citations.
At a Glance
Classification: Synthetic growth hormone-releasing hormone (GHRH/GHRF) analogue; growth hormone secretagogue
Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone designed to stimulate the body's own pituitary release of growth hormone and increase downstream IGF-1 signaling. Unlike many research peptides, tesamorelin has undergone extensive controlled human clinical testing and has an FDA-approved medical indication. It was first approved in the United States in 2010 and is currently marketed as Egrifta formulations for reducing excess abdominal fat in adults with HIV-associated lipodystrophy. It is not FDA-approved for general weight-loss management, and its long-term cardiovascular safety has not been established. Research beyond the approved indication has investigated liver fat, metabolic dysfunction-associated steatotic liver disease in people with HIV, inflammatory signaling, and neurocognitive outcomes.
What Is Tesamorelin?
Tesamorelin is a synthetic peptide based on the 44-amino-acid sequence of human growth hormone-releasing hormone. GHRH is produced naturally by the hypothalamus and signals the anterior pituitary gland to release growth hormone. Tesamorelin preserves this biological activity while incorporating a structural modification intended to increase stability relative to endogenous GHRH. Rather than supplying growth hormone directly, tesamorelin stimulates the pituitary to increase endogenous pulsatile growth-hormone secretion. This subsequently increases production of insulin-like growth factor 1 (IGF-1). That distinction is important. Tesamorelin is not human growth hormone, although it acts through the physiological GH/IGF-1 axis. Clinical development focused heavily on abnormal visceral-fat accumulation in people with HIV receiving antiretroviral therapy. Large randomized trials demonstrated significant reductions in visceral adipose tissue, leading to FDA approval.
What Are Researchers Studying?
HIV-associated visceral adiposity
This is tesamorelin's best-established research area and its FDA-approved indication. Large randomized controlled trials found that tesamorelin selectively reduced visceral abdominal fat in adults with HIV-associated abdominal adiposity. A pooled analysis of two Phase 3 studies involving 806 participants found a treatment effect corresponding to approximately a 15.4% reduction in visceral adipose tissue at 26 weeks compared with placebo. Importantly, this does not make tesamorelin a general weight-loss medication.
Liver fat
Researchers subsequently investigated whether tesamorelin's effects on visceral adiposity and the GH/IGF-1 axis also influence fat accumulation in the liver. A randomized study found reductions in both visceral fat and liver fat after six months of treatment in people with HIV and abdominal fat accumulation. A later 12-month randomized trial in people with HIV and fatty liver disease reported a significantly greater reduction in hepatic fat fraction with tesamorelin than placebo. Liver-fat reduction is an active research area and should be distinguished from tesamorelin's FDA-approved indication.
Metabolic dysfunction-associated steatotic liver disease
Researchers have examined tesamorelin in people with HIV who also have metabolic liver disease. In a 12-month randomized study, tesamorelin reduced hepatic fat fraction relative to placebo. Approximately 35% of tesamorelin-treated participants reached a hepatic fat fraction below 5%, compared with 4% receiving placebo. Related biopsy research has also examined fibrosis, inflammation, and hepatic immune pathways. These findings are clinically interesting but have not expanded tesamorelin's FDA-approved indication to treatment of fatty liver disease.
Visceral versus subcutaneous fat
One of the distinctive features of tesamorelin research is its effect on fat distribution rather than simply total body weight. Clinical trials found reductions in visceral adipose tissue without comparable loss of subcutaneous abdominal or limb fat. This helps explain why describing tesamorelin merely as a "fat-loss peptide" or "weight-loss peptide" is misleading. Its clinically demonstrated effect is considerably more specific.
Adipose tissue quality and metabolic health
Researchers have investigated whether tesamorelin changes characteristics of adipose tissue beyond reducing its volume. A later analysis of randomized-trial participants found changes in CT-measured visceral and subcutaneous fat density among tesamorelin responders, suggesting changes in adipocyte characteristics in addition to changes in visceral-fat quantity. The clinical significance of these imaging findings remains an area of investigation.
Inflammation and immune signaling
Because visceral adiposity is associated with inflammatory and metabolic signaling, researchers have examined whether reducing visceral fat with tesamorelin changes inflammatory biomarkers. Studies have reported changes in several markers associated with adipose biology, fibrinolysis, T-cell activity, and monocyte activation. These biomarker findings do not independently establish improvements in long-term clinical outcomes.
Neurocognitive function
Researchers have investigated whether reducing abdominal adiposity and increasing IGF-1 might affect neurocognitive impairment in people with HIV. A 2025 Phase 2 trial involving 73 participants found that tesamorelin reduced waist circumference but did not produce a statistically significant improvement in neurocognitive performance compared with standard care. This is a useful example of a biologically plausible hypothesis that has not yet translated into clear clinical benefit.
How Does It Work?
Tesamorelin mimics endogenous growth hormone-releasing hormone. It binds GHRH receptors on somatotroph cells in the anterior pituitary, stimulating synthesis and release of growth hormone. Growth hormone subsequently stimulates production of IGF-1, primarily in the liver and other tissues. The GH/IGF-1 axis influences: - Lipolysis and fat metabolism - Body composition - Protein metabolism - Glucose metabolism - Tissue growth and repair - Hepatic metabolism Tesamorelin's effect on visceral adipose tissue appears related to restoration or augmentation of physiological GH signaling. An important pharmacological distinction is that tesamorelin stimulates endogenous GH secretion rather than continuously supplying exogenous GH. This retains more of the body's normal pituitary secretory regulation, although tesamorelin still substantially affects the GH/IGF-1 axis.
What Does the Research Show?
Human research
Human evidence for tesamorelin is extensive relative to most peptides catalogued by Aminodex. A pivotal 2007 randomized controlled trial enrolled 412 adults with HIV and abdominal fat accumulation. After 26 weeks, visceral adipose tissue decreased approximately 15.2% in the tesamorelin group while increasing approximately 5% with placebo. Triglycerides and cholesterol-related measures also improved. Subsequent Phase 3 studies reproduced reductions in visceral adipose tissue. A pooled analysis of two Phase 3 trials included 806 participants, with 543 receiving tesamorelin and 263 receiving placebo during the first 26 weeks. Visceral fat decreased significantly with tesamorelin, producing an estimated treatment effect of approximately 15.4%. Longer-term research found that reductions could be maintained with continued treatment. However, visceral fat tended to reaccumulate after tesamorelin was discontinued. Human research has subsequently expanded into liver fat, metabolic liver disease, inflammatory pathways, contemporary HIV treatment regimens, and neurocognitive outcomes.
Animal research
Animal and laboratory studies helped characterize GHRH physiology and tesamorelin's effects during development. However, unlike many experimental peptides, the scientific case for tesamorelin no longer depends primarily on animal studies. Large randomized human trials provide direct evidence for its approved indication. Animal research remains useful for exploring GH/IGF-1 signaling and potential applications outside the established clinical indication.
In-vitro research
Cellular and receptor-based research has characterized tesamorelin's activity at the GHRH receptor and downstream GH/IGF-1 signaling. Mechanistic laboratory research also helps researchers investigate how alterations in GH signaling influence adipocytes, hepatocytes, metabolic pathways, and inflammatory processes. Because extensive human clinical data exist, in-vitro evidence is primarily useful for explaining mechanism rather than establishing efficacy.
Notable Studies
Metabolic Effects of a Growth Hormone-Releasing Factor in Patients With HIV
humanResearchers randomized 412 adults with HIV-associated abdominal fat accumulation to tesamorelin or placebo for 26 weeks. Visceral adipose tissue decreased 15.2% in participants receiving tesamorelin and increased 5.0% with placebo. Tesamorelin also produced improvements in triglycerides and the ratio of total cholesterol to HDL cholesterol. The study provided major controlled human evidence that augmenting endogenous GH secretion could selectively reduce visceral adiposity in this population.
Limitations: Participants specifically had HIV-associated abdominal adiposity, so the findings should not be generalized to ordinary obesity. The trial was 26 weeks long and could not establish long-term cardiovascular outcomes.
View publication →Effects of Tesamorelin, a Growth Hormone-Releasing Factor, in HIV-Infected Patients With Abdominal Fat Accumulation: A Randomized Placebo-Controlled Trial With a Safety Extension
humanResearchers studied 404 adults with HIV-associated central fat accumulation. After six months, visceral adipose tissue decreased approximately 10.9% with tesamorelin versus 0.6% with placebo. Participants continuing tesamorelin for 12 months achieved approximately an 18% reduction from baseline. When participants were switched from tesamorelin to placebo, the previous reduction in visceral fat was rapidly lost.
Limitations: The study population had HIV-associated abnormal fat accumulation and should not be treated as a general obesity population. Benefits were dependent on continued treatment, and the study did not establish long-term cardiovascular benefit.
View publication →Effects of Tesamorelin on Visceral Fat and Liver Fat in HIV-Infected Patients With Abdominal Fat Accumulation: A Randomized Clinical Trial
humanResearchers investigated whether tesamorelin affected liver fat in addition to visceral abdominal fat. Forty-eight participants received study treatment. Tesamorelin significantly reduced visceral adipose tissue compared with placebo and also produced a modest but significant reduction in liver fat. The study helped establish liver metabolism as an important area of subsequent tesamorelin research.
Limitations: The study was relatively small and involved people with HIV and abdominal fat accumulation. Liver-fat reduction was modest, and the study did not establish tesamorelin as a treatment for liver disease.
View publication →Effects of Tesamorelin on Non-Alcoholic Fatty Liver Disease in HIV: A Randomised, Double-Blind, Multicentre Trial
humanResearchers enrolled approximately 60 people with HIV and hepatic fat fraction of at least 5%. After 12 months, tesamorelin produced an absolute treatment effect of approximately −4.1 percentage points in hepatic fat fraction, corresponding to a relative reduction of approximately 37% from baseline compared with placebo. Approximately 35% of tesamorelin-treated participants reached a hepatic fat fraction below 5%, compared with 4% receiving placebo.
Limitations: The study was relatively small and specifically involved people with HIV and fatty liver disease. The findings do not establish efficacy for fatty liver disease in the general population and have not resulted in an FDA-approved liver-disease indication.
View publication →Effects of Tesamorelin on Neurocognitive Impairment in Persons With HIV and Abdominal Obesity
humanResearchers randomized 73 people with virally suppressed HIV, abdominal obesity, and neurocognitive impairment to tesamorelin or standard care for six months. Tesamorelin significantly reduced waist circumference. However, improvement in neurocognitive performance did not differ significantly between groups. This study is particularly informative because it demonstrates that tesamorelin's established effects on abdominal adiposity and IGF-1 do not automatically translate into benefits in unrelated clinical outcomes.
Limitations: The study was relatively small, was not placebo-controlled, and may have been underpowered to detect smaller neurocognitive effects. The findings do not exclude all possible neurological effects but provide no clear evidence of cognitive benefit from the intervention studied.
View publication →What We Still Don't Know
Despite extensive clinical research, important questions remain: - Long-term cardiovascular outcomes - Whether reducing visceral adipose tissue translates into fewer cardiovascular events - Long-term effects of sustained increases in IGF-1 - Which patients are most likely to respond - The clinical significance of tesamorelin-induced changes in liver fat - Whether liver-related effects extend to populations without HIV - Whether changes in inflammatory biomarkers produce meaningful clinical benefits - Long-term metabolic effects in contemporary HIV treatment populations - Whether experimental applications outside HIV-associated lipodystrophy offer clinically meaningful benefit - The consequences of long-term treatment followed by discontinuation FDA labeling specifically notes that long-term cardiovascular safety has not been established.
Related Compounds
Recent publications
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Sources & References
- Falutz J, Allas S, Blot K, et al. Metabolic Effects of a Growth Hormone-Releasing Factor in Patients With HIV. New England Journal of Medicine. 2007;357(23):2359–2370. doi:10.1056/NEJMoa072375.
- Falutz J, Potvin D, Mamputu JC, et al. Effects of Tesamorelin, a Growth Hormone-Releasing Factor, in HIV-Infected Patients With Abdominal Fat Accumulation: A Randomized Placebo-Controlled Trial With a Safety Extension. Journal of Acquired Immune Deficiency Syndromes. 2010.
- Stanley TL, Feldpausch MN, Oh J, et al. Effect of Tesamorelin on Visceral Fat and Liver Fat in HIV-Infected Patients With Abdominal Fat Accumulation: A Randomized Clinical Trial. JAMA. 2014;312(4):380–389.
- Fourman LT, Czerwonka N, Feldpausch MN, et al. Effects of Tesamorelin on Non-Alcoholic Fatty Liver Disease in HIV: A Randomised, Double-Blind, Multicentre Trial. Lancet HIV. 2019.
- Russo SC, Ockene MW, Arpante AK, et al. Efficacy and Safety of Tesamorelin in People With HIV on Integrase Inhibitors. AIDS. 2024. doi:10.1097/QAD.0000000000003965.
- Effects of Tesamorelin on Neurocognitive Impairment in Persons With HIV and Abdominal Obesity. 2025.
- U.S. Food and Drug Administration. EGRIFTA WR (tesamorelin) Prescribing Information. Revised 2025.
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