# Tesamorelin Liver Fat: What the NAFLD Research Shows > Tesamorelin liver fat research, cited: a 12-month Lancet HIV trial cut hepatic fat 37%, a JAMA trial cut hepatic lipid 2.9%, and a 2026 meta-analysis pooled a 4.28% reduction — all in HIV-associated fatty liver. The hepatic-fat-fraction trials, the 35%-versus-4% threshold result, and the transcriptomic correlate — read at the line a metric crosses. ## The short version Here is the tesamorelin liver fat story in plain terms. NAFLD (non-alcoholic fatty liver disease) is fat building up in the liver without alcohol as the cause; under 5% liver fat is considered normal. In a 12-month trial of HIV patients with fatty liver, tesamorelin cut liver fat by about a third, and 35% of treated patients dropped below that 5% normal line versus 4% on placebo. A liver-tissue study suggested why: it switched on fat-burning genes and quieted inflammation. All of this was measured in HIV-associated fatty liver, not general NAFLD — it is studied, not approved, for the liver. ## The hepatic-fat-fraction trials The signature tesamorelin liver fat finding comes from a 12-month randomized, double-blind, multicentre Lancet HIV trial of 61 HIV patients with NAFLD. Tesamorelin 2 mg/day reduced hepatic fat fraction — the share of the liver that is fat, measured by MRI — by 37% relative to placebo (P=0.016) [6]. The threshold result is the cleaner headline: 35% of tesamorelin recipients reached a hepatic fat fraction below 5% (the normal line) versus 4% on placebo (P=0.0069) [6]. The authors noted further study of long-term liver histology is needed. The earlier 6-month JAMA trial of 50 antiretroviral-treated HIV adults measured the same direction: a net hepatic-lipid reduction of -2.9% (P=0.003) alongside a -42 cm2 visceral-fat treatment effect (P=0.005) [3]. Pooling the evidence, a 2026 meta-analysis of five randomized trials reported a hepatic-fat-fraction reduction of -4.28% (P<0.001), with no serious adverse events [12]. A 2024 trial in HIV patients on integrase-inhibitor regimens with steatotic liver disease found a hepatic-fat reduction of -4.2% versus -0.5% on placebo (P=0.01), confirming the effect in the modern antiretroviral era [10]. Every one of these figures was measured in HIV-associated fatty liver disease — see where [tesamorelin and liver fat](/liver-fat) stands against general NAFLD below. ## How does tesamorelin affect the liver in NAFLD? Liver-tissue transcriptomics after 12 months of tesamorelin in HIV patients with NAFLD showed upregulated oxidative-phosphorylation gene sets — the cell's fat-burning machinery — and downregulated inflammatory and tissue-remodeling pathways [8]. Transcriptomics reads which genes a tissue has switched on or off, so this is a direct molecular readout from the liver itself, not an inference from blood markers. That gene-level shift — more fat-oxidation capacity, less inflammatory and fibrotic signaling — is a mechanistic correlate for the observed drop in hepatic fat, and it aligns with the visceral-fat-mediated improvement seen in the enzyme data below. ## Is tesamorelin a potential treatment for non-alcoholic fatty liver disease? In the 12-month Lancet HIV trial (n=61), tesamorelin 2 mg/day cut hepatic fat fraction by 37% relative to placebo (P=0.016), and 35% versus 4% of patients reached a fraction below 5% (P=0.0069) [6]. The authors called for further study of liver histology. It is studied in HIV-associated NAFLD, not approved for general NAFLD. ## Can tesamorelin reduce liver fat? In a 6-month JAMA trial (n=50), the net reduction in hepatic lipid-to-water percentage was -2.9% (P=0.003) [3]; a 2026 meta-analysis of five trials reported a pooled hepatic-fat-fraction reduction of -4.28% [12]. All such data are in HIV-associated fatty liver disease, not general-population NAFLD. ## The IGF-1 and liver-enzyme link The liver effect tracks the IGF-1 system. In a secondary analysis of 61 adults with HIV and NAFLD, lower hepatic IGF1 expression was associated with greater steatosis (fat buildup) and worse glucose parameters; GHRH administration raised circulating IGFBP-1 and IGFBP-3 while lowering IGFBP-2 and IGFBP-6 [13]. IGFBPs are the binding proteins that escort IGF-1 through the blood, so the shift describes a reorganization of the whole IGF-1 transport system, not just a single hormone bump. The system that drives the fat loss is the same one that touches the liver. The enzyme data point the same way. Among HIV patients with elevated baseline transaminases (the liver enzymes ALT and AST, which rise when liver cells are stressed), tesamorelin visceral-fat responders showed greater reductions in ALT (-8.9 vs +1.4 U/L, P=0.004) and AST (-3.8 vs +0.4 U/L, P=0.04) than non-responders over 26 weeks [14]. The liver-enzyme improvement followed the visceral-fat reduction — the fat loss appears to be the mediating mechanism, not a separate direct effect, consistent with the inflammatory-marker findings on the [research](/research) page. This is [hepatic fat in NAFLD research](/liver-fat) read as one connected system. ## What the liver data does not yet show The honest line on tesamorelin liver fat runs through the population. Every hepatic-fat figure here — the 37% relative reduction [6], the -2.9% net hepatic lipid [3], the pooled -4.28% [12], the 2024 integrase-inhibitor-era result [10] — was measured in HIV-positive adults on antiretroviral therapy with HIV-associated fatty liver. None was a general-population NAFLD trial. Two gaps follow. First, generalizability: whether the same effect holds in non-HIV metabolic-dysfunction-associated steatotic liver disease (MASLD) is mechanistically plausible but not established by a large trial. Second, histology: the Lancet HIV authors explicitly noted that longer-term effects on liver tissue structure — inflammation and fibrosis on biopsy, not just fat fraction on MRI — need further study [6]. A reduction in measured liver fat is a real and reproducible endpoint, but it is not the same as a demonstrated change in long-term liver disease outcomes. Tesamorelin is approved only for HIV-associated lipodystrophy; its use for any fatty-liver indication is off-label and investigational [5]. --- A clear-light reading of the tesamorelin record — every trial figure logged at the snow-line where the approved HIV-lipodystrophy use ends and the off-label questions begin; a luminous reference plate, not a clinic, a pharmacy, or a prescription.