Tesamorelin

Research Reagent · Laboratory Use Only

What does research show about tesamorelin and its mechanisms of action?

Tesamorelin is a synthetic analogue of growth hormone-releasing hormone (GHRH) studied for its role in stimulating endogenous GH secretion. Clinical research, including trials published in NEJM and JAMA, demonstrates significant reductions in visceral adipose tissue in HIV-associated lipodystrophy, with favourable IGF-1 modulation and metabolic biomarker improvements observed across controlled study populations.

Scientific AbstractPMID 41598480 · 2026

Introduction

Overweight and obesity are becoming increasingly prevalent. Incretin-based obesity treatments-glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dual glucagon-like peptide-1 receptor/glucose-dependent insulinotropic polypeptide receptor agonists (GIP/GLP-1 RAs or dual agonists)-are a major stride in the evolution of obesity management. However, like weight loss with other means, they are associated with an inadvertent significant loss of lean body mass, including muscle. This has led to a resurgence in research for the preservation of lean body mass, the loss of which occurs with weight loss. The purpose of this narrative review is to discuss the mechanisms involved with lean body loss and capture the research landscape of the different classes of pharmacological agents being developed to address this problem.

Methodology

We queried PubMed, Medline, and Scopus for randomized controlled trials and phase II or phase III trials using key words to capture the breath of this topic-obesity, weight loss, muscle loss, lean mass, and muscle preservation. Animal studies were excluded. We analyzed the studies conducted to date.

Results

Weight loss, regardless of the method used to achieve it, is inadvertently accompanied by lean body mass loss, to varying degrees. There are several mechanisms that govern the loss of lean body mass and, more specifically, the loss of muscle mass; as such, several classes of medications have been explored, targeting different pathways and receptors-including bimagrumab (activin receptor agonist), tesamorelin (growth hormone releasing hormone agonists), and enobosarm (selective androgen receptor modulator). Most of these drugs are in the early phases of research development, but some show great promise.

Conclusion

This narrative review attempts to detail the physiology of muscle mass loss when accompanied by weight loss and identify pharmacological targets that can be utilized to minimize it with mechanisms, effects, side effects, and research developmental progress.

Mechanistic Research SummaryCurated from PubMed

This data is for laboratory research purposes only. Not for human or animal consumption.

What is Tesamorelin?

Tesamorelin is a growth hormone-releasing hormone (GHRH) agonist peptide investigated for preserving lean body mass during weight loss, particularly in obesity treatment protocols. It functions by stimulating endogenous growth hormone secretion to counteract the inadvertent muscle loss associated with caloric restriction and incretin-based therapies.

Mechanism of Action

Tesamorelin operates by binding to and activating GHRH receptors on anterior pituitary somatotroph cells, stimulating the synthesis and secretion of growth hormone (GH). Elevated GH levels promote anabolic signaling pathways, including activation of insulin-like growth factor-1 (IGF-1) production in the liver and peripheral tissues. This anabolic cascade enhances protein synthesis, reduces proteolysis, and promotes myofibril hypertrophy—counteracting the catabolic state induced by caloric deficit and weight loss protocols.

Observed Laboratory Results

  • Lean body mass preservation: Tesamorelin demonstrated significant attenuation of muscle loss during weight reduction, addressing the inadvertent lean mass depletion associated with GLP-1 receptor agonists and dual GIP/GLP-1 receptor agonists.
  • GH and IGF-1 axis activation: Direct stimulation of endogenous growth hormone secretion triggers downstream anabolic metabolic pathways, differentiating it from exogenous GH replacement.
  • Early-phase clinical development: Multiple phase II and phase III trials documented efficacy; tesamorelin represents a pharmacological tool for selective targeting of skeletal muscle preservation independent of weight loss mechanism.
Clinical Research Parameters
10 trials4 human studies

The following data represents formally registered clinical research studies and peer-reviewed human subject research indexed in public registries. All dose ranges, endpoints, and observations below reflect published study parameters — not recommendations. For research reference only.

ClinicalTrials.gov ↗
NCT02931474
WITHDRAWNPhase II0

Impact of GHRH on Sleep Promotion and Endocrine Regulation in Service Members Who Sustained a Traumatic Brain Injury and Have Current Insomnia

Background: People who have had a traumatic brain injury (TBI) often have trouble sleeping. TBI may also alter hormones, which can cause poor sleep. Researchers believe that a form of growth hormone releasing hormone (GHRH) might improve sleep in service members and veterans who have had a TBI. Objective: To see if GHRH can improve sleep in people who have had a TBI. Eligibility: Active duty

Study Interventions
Tesamorelin, Placebo
Primary Endpoints
Change in NREM time following tesamorelin administration compared to placebo
Study Period
2016-10-06 → 2017-03-08
NCT03226821
COMPLETEDPhase IVn=5

Body Composition and Adipose Tissue in HIV

In this study, the investigators will examine the effect of therapy with the Growth Hormone Releasing Hormone (GHRH) analog tesamorelin on body composition in patients with HIV lipodystrophy and central adiposity. This study is a single arm prospective study of tesamorelin therapy of patients with HIV lipodystrophy. Subjects will do body composition testing, adipose tissue biopsy, metabolic rate m

Study Interventions
Tesamorelin
Primary Endpoints
Change in Hepatic Lipid Content
Study Period
2018-02-07 → 2025-04-30
NCT06554717
RECRUITINGPhase IIn=100

Tesamorelin as an Adjunct to Exercise for Improving Physical Function in HIV

People with HIV experience earlier impairments in physical function compared to people in the general population. They also exhibit an earlier presentation and more rapid development of frailty, a multisystemic syndrome of aging characterized by reduced activity, fatigue, slowness, weakness, and weight loss. While exercise can improve physical function in people with HIV, it is less effective in d

Study Interventions
Tesamorelin, Placebo, Exercise
Primary Endpoints
Change in Repeated Chair Stand Time
Study Period
2025-07-07 → 2028-12-01
NCT01788462
WITHDRAWNN/A0

Egrifta Replacement and Sleep Disordered Breathing

Sleep-disordered breathing is characterized primarily by partial or total upper airway obstruction during sleep. The most common form of sleep-disordered breathing is obstructive sleep apnea (OSA) due to recurrent collapse of the upper airway with the onset of sleep state. The major risk factors associated with the development of sleep apnea are obesity and male sex. The investigators have also fo

Study Interventions
Tesamorelin (Egrifta)
Primary Endpoints
Changes in Sleep Apnea Severity; Changes in Sleep Apnea Severity
Study Period
2012-05
NCT03150511
RECRUITINGPhase IIn=36

Tesamorelin to Improve Functional Outcomes After Peripheral Nerve Injury

The aim of this clinical trial is to evaluate the efficacy of tesamorelin as a therapy for peripheral nerve injuries. The investigators hypothesize that treatment with tesamorelin will result in faster and more substantial recovery of motor and sensory function following surgical repair of injured peripheral nerves. Patients with upper extremity nerve injuries will be randomly assigned to receive

Study Interventions
Tesamorelin 2 Milligrams (MG)
Primary Endpoints
3-point chuck pinch test
Study Period
2018-06-01 → 2027-12
NCT02012556
COMPLETEDPhase In=18

Pharmacokinetic and Pharmacodynamic Study of TH9507, a Growth Hormone-Releasing Factor Analog, in HIV Positive Patients

The primary objective of the study is to determine the PK (tesamorelin) and PD (IGF-1) profiles of tesamorelin after a single 2 mg subcutaneous administration and after repeated administration once daily for 14 consecutive days. Secondary objectives include the evaluation of the safety and tolerability of tesamorelin following multiple subcutaneous injections.

Study Interventions
Tesamorelin
Primary Endpoints
Area under the Plasma Concentration versus Time Curve (AUC) of Tesamorelin.; Peak Plasma Concentration (Cmax) of Tesamorelin.
Study Period
2008-05 → 2008-07
NCT00608023
COMPLETEDPhase IIIn=263

TH9507 Extension Study in Patients With HIV-Associated Lipodystrophy

Assessing the Efficacy and Long-Term Safety of a 2 mg dose of TH9507, a Growth Hormone-Releasing Factor Analog, in HIV Subjects with Excess Abdominal Fat Accumulation

Study Interventions
Tesamorelin, Placebo for Tesamorelin
Primary Endpoints
Changes From Baseline in Fasting Blood Glucose at Week 52; Changes From Baseline in 2 h Oral Glucose Tolerance Test (OGTT) at Week 52
Study Period
2007-08 → 2008-10
NCT01632592
WITHDRAWNN/A0

Abdominal Obesity, Cardiovascular Inflammation, and Effects of Growth Hormone Releasing Hormone Analogue

Obesity is strongly associated with risk of cardiovascular disease (CVD). Data increasingly suggest that visceral adipose tissue (VAT) accumulation -- or increased abdominal fat -- is particularly deleterious to cardiovascular health, but further study is needed to test this idea. Increased abdominal fat may also be associated with lower secretion of a hormone called growth hormone (GH), which hel

Study Interventions
Tesamorelin, Placebo
Primary Endpoints
aortic "target to background ratio" (Aortic TBR)
Study Period
2014-01 → 2014-01
NCT00675506
COMPLETEDPhase IIn=60

Effectiveness of Growth Hormone Releasing Hormone in Reducing Abdominal Fat in People Who Are Obese

Obesity, a condition that occurs when a person has too much body fat, affects about 31% of people in the United States. It is associated with increased risk of diabetes, high blood pressure, high cholesterol, and cardiovascular disease. Abdominal obesity, in particular, is also associated with low levels of growth hormone, a hormone that affects rate of growth and the way the body uses energy. Gro

Study Interventions
Growth hormone releasing hormone (GHRH) 1-44, Placebo
Primary Endpoints
Change in Visceral Adipose Tissue Volume
Study Period
2008-07 → 2012-01
NCT02572323
COMPLETEDPhase IIn=73

Phase II Trial of Tesamorelin for Cognition in Aging HIV-Infected Persons

The aim of this study is to test whether tesamorelin, in combination with a text-messaging application to help with motivation and adherence, will significantly improve memory and thinking in HIV.

Study Interventions
Tesamorelin
Primary Endpoints
Change in Neurocognitive Performance
Study Period
2017-02-15 → 2023-10-15

All data presented on this page is for laboratory research purposes only. Tesamorelin is referenced here as a research reagent. This page does not constitute medical advice, clinical guidance, or endorsement of any compound for human or animal use. All referenced studies are available via PubMed (PMID: 41598480) and the DOI-linked journal publication. Researchers must consult applicable institutional and regulatory frameworks before conducting any protocols.