# Tesamorelin Research Overview — Get Peptides USA > A literature summary of tesamorelin, a synthetic GHRH analogue FDA-approved for HIV-associated lipodystrophy. Covers pituitary mechanism, visceral fat RCT data, hepatic effects, and off-label research context. A 44-amino-acid synthetic version of the hypothalamic GH-releasing signal — FDA-approved for one specific HIV indication, studied off-label for visceral fat and liver health beyond that population. ## The short version Tesamorelin is a synthetic analogue of the body's own growth hormone-releasing hormone (GHRH) — the signal the hypothalamus sends to tell the pituitary to release growth hormone. It is 44 amino acids long and carries a small chemical modification at one end that makes it more stable in the bloodstream than native GHRH. Here is where the approval picture matters most: tesamorelin is FDA-approved, but only to reduce excess abdominal fat in HIV-positive adults who developed a specific fat-redistribution condition called lipodystrophy as a side effect of antiretroviral therapy [2]. That is a real, meaningful approval backed by multiple randomized controlled trials. Every other proposed use — reducing visceral fat in people without HIV, improving liver fat, cognitive enhancement, general anti-aging — is off-label and investigational [2]. It is also banned in competitive sport under WADA's S2 category [2]. This page summarizes what the published studies found; it does not advise on use or list a dose. ## What it is Tesamorelin (also designated TH9507) is a 44-amino-acid synthetic peptide corresponding to the full sequence of human GHRH(1-44)-NH2, with a trans-3-hexenoic acid group conjugated to the nitrogen at the N-terminus. That modification — a small lipophilic cap — is the key structural difference from native GHRH: it makes the peptide resistant to cleavage by dipeptidyl peptidase-IV (DPP-IV), the enzyme that rapidly degrades native GHRH in the bloodstream. The result is a longer plasma half-life and stronger, more sustained pituitary stimulation than native GHRH would achieve at the same dose. The empirical formula of the free base is C221H366N72O67S. It is supplied clinically as the acetate salt. It is a prescription drug in its approved indication, not a freely available supplement. ## How it works Tesamorelin binds the growth hormone-releasing hormone receptor (GHRH-R) on the somatotroph cells of the anterior pituitary. That binding activates a Gs protein, which raises cyclic AMP (cAMP) via adenylyl cyclase and activates protein kinase A (PKA), ultimately stimulating both the synthesis and the pulsatile secretion of endogenous growth hormone [1][4]. The released GH then acts on the liver, driving production of IGF-1. Together, GH and IGF-1 promote **lipolysis preferentially in visceral adipose tissue** — the metabolically active fat depot packed around the organs in the abdomen — which is the mechanistic basis for tesamorelin's approved indication [1][3]. A key point that the research consistently emphasizes: because tesamorelin amplifies the body's own pulsatile GH secretion rather than supplying a constant exogenous source, its metabolic and hormonal profile differs from recombinant GH. In healthy men given tesamorelin for two weeks, both mean overnight GH and serum IGF-1 rose significantly, yet fasting glucose and insulin-stimulated glucose uptake were not significantly changed [4] — a pattern that distinguishes GHRH-analogue stimulation from direct GH replacement. ## What the research shows **Visceral fat in HIV lipodystrophy.** The approved indication rests on a replicated clinical signal. A 2026 meta-analysis of five RCTs in HIV-positive adults with lipodystrophy found that tesamorelin produced a mean reduction in visceral adipose tissue of -27.71 cm² (95% CI -38.37 to -17.06; P<0.001), with concurrent reductions in trunk fat (-1.18 kg), hepatic fat fraction (-4.28%), and an increase in lean body mass (+1.42 kg), all statistically significant and without serious adverse events [1]. A landmark 2014 JAMA RCT in 50 antiretroviral-treated HIV adults gave a more granular view: tesamorelin at 2 mg/day produced a treatment effect of -42 cm² in visceral fat (P=0.005) and reduced hepatic lipid-to-water percentage by a net -2.9% (P=0.003), with the hepatic fat reduction potentially relevant to HIV-associated non-alcoholic fatty liver disease [3]. **Duration and rebound.** The 52-week program — 273 on tesamorelin versus 137 on placebo — sustained visceral fat reduction at roughly -18% over a full year (P<0.001 vs baseline). The catch: visceral fat reaccumulated after discontinuation, and the benefit appears contingent on continued dosing [5]. Glucose parameter changes over the 52 weeks were not clinically significant [5]. **GH-axis effects in non-HIV adults.** The mechanistic picture in a healthy, non-HIV population comes from the 2011 study in 13 healthy men: two weeks of tesamorelin raised mean overnight GH by +0.5 µg/L (P=0.004) and IGF-1 by +181 µg/L (P<0.0001), while neither fasting glucose nor insulin-stimulated glucose uptake changed significantly [4]. This demonstrates the pulsatile-preservation feature but does not establish long-term effects or clinical benefit in a healthy population. **Liver safety.** The NIH LiverTox monograph assigns tesamorelin a likelihood score of E — unlikely to cause clinically apparent liver injury — noting no reported attributable liver-injury cases and no de novo serum-enzyme elevations in trials [2]. ## Reported effects, cautions & safety The research.json source for tesamorelin records no community-sourced real-world signals — the compound's clinical setting is specific enough that formal trial data dominate, and off-label anecdotal reports are not compiled here. The cautions are drawn entirely from the literature and the regulatory record. **Key cautions from the literature:** - *Approval is narrow.* The FDA approval covers HIV-associated lipodystrophy in adults on antiretroviral therapy, and that is its only approved indication anywhere. Anti-aging, body-composition, cognitive, or liver applications in non-HIV populations are off-label and unsupported by large-scale trials [2]. - *Effect is lost on discontinuation.* Visceral fat reaccumulates within weeks of stopping. Benefits require ongoing dosing, which has implications for long-term risk exposure [5]. - *IGF-1 elevation and malignancy.* GH-axis stimulation raises serum IGF-1, a mitogenic growth factor. Trials over 52 weeks showed no excess malignancy signal, but long-term oncologic-safety data are limited, and active malignancy is a labeled contraindication [1][5]. - *Glucose monitoring.* Modest glucose perturbation can occur; individuals with prediabetes or dysglycemia warrant monitoring, though dedicated trials did not find clinically significant HbA1c changes [4][5]. - *WADA S2 prohibition.* Tesamorelin is prohibited in sport as a GHRH analogue under the S2 category (peptide hormones, growth factors, related substances and mimetics), in- and out-of-competition [2]. - *Injection only.* It is administered by subcutaneous injection, not orally. Research-grade material lacks the purity and potency oversight of the approved pharmaceutical product. ## Where it fits on the GH-axis desk Among the three compounds covered here, tesamorelin is the only one with a genuine FDA approval — but that approval is tightly bounded by indication, population, and duration context. Its mechanism (hypothalamic → pituitary → GH → IGF-1 → lipolysis) is well-characterized and represents the upstream, amplifying end of the GH axis, working through the body's own pulsatile rhythm rather than supplying exogenous hormone. Read alongside [ipamorelin](/ipamorelin), which activates the pituitary from a different receptor (GHS-R1a rather than GHRH-R) and from a different discovery lineage, the contrast illuminates how multiple pharmacological approaches can converge on the same downstream GH pulse. [MOTS-c](/mots-c), meanwhile, intervenes at the mitochondrial-metabolic level, bypassing the pituitary axis entirely. See all three on the [comparison page](/compare). ![Tesamorelin pituitary receptor binding and GH-axis signaling — abstract cold gunmetal cyan illustration](/images/tesamorelin.webp) --- A reference desk, not a clinic: this site reads the GH-axis literature so you can see what the evidence actually says.