# Tesamorelin Dosage in the Studies: Doses, Route and Half-Life > Tesamorelin dosage as studied: 2 mg/day subcutaneously in the pivotal trials, a short plasma half-life against sustained IGF-1, and once-daily rationale. Research-context only, not a recommendation. What investigators administered, by which route, and why a short-lived peptide is dosed once daily. ## The gist In the trials, tesamorelin was given as a 2 mg shot under the skin once a day. The peptide itself clears from the blood fast — a matter of minutes — but the IGF-1 it raises (the liver's growth signal) stays up much longer, which is why once-daily dosing worked. Everything below describes what researchers measured in studies. None of it is a dosing instruction: tesamorelin's only approved use is in HIV-associated lipodystrophy, and research-grade material is supplied for laboratory work, not for people to inject. ## Doses used in the studies The studied tesamorelin dosage per day in the pivotal program was 2 mg subcutaneously once daily — the dose in both Phase 3 trials and the original FDA-approved regimen [1][2]. A 1 mg once-daily arm appears in secondary studies, including a cognition trial and a lower arm of a type-2-diabetes safety trial. A later FDA-approved reformulation uses a higher-concentration once-daily subcutaneous regimen, but the extensively studied paradigm is once-daily 2 mg [5]. These figures describe what was administered to defined trial populations. They are not a recommendation, and no human dosing instruction follows from them — the framing throughout is "studied at 2 mg/day in HIV patients," not a protocol to copy. We index every figure under [doses used in the studies](/dosage). ## Tesamorelin half-life and pharmacokinetics Plasma exposure is short. Population pharmacokinetic modeling reported an apparent plasma clearance of about 1,060 L/h, with no clinically relevant demographic covariates, and a roughly 13% increase in absorbed fraction by day 14 versus day 1 [12]. Secondary sources (the FDA label, Mayo Clinic) describe a terminal half-life on the order of 26-38 minutes [5]. The pharmacology that matters is the gap between the two timescales: the peptide clears in minutes, but the IGF-1 it raises persists across the dosing interval — which is the rationale for once-daily administration in the trials [4][12]. A short-lived signal can produce a long-lived downstream effect. We summarize this as [tesamorelin half-life](/dosage). ## Route and formulation in the trials The only route studied in clinical trials, and the only FDA-approved route, is subcutaneous injection at an abdominal site [1]. Tesamorelin is supplied as a lyophilized (freeze-dried) powder that requires reconstitution; the trans-3-hexenoic-acid N-terminal cap blocks the DPP-IV cleavage that rapidly inactivates native GHRH, which is what makes a once-daily injectable feasible [3]. The FDA label specifies refrigerated storage and use of the reconstituted solution within a defined window [5]. The abdominal injection site is not incidental. Because the studied effect is reduction of abdominal visceral fat, the trials standardized subcutaneous abdominal administration, and the pharmacokinetic and efficacy data above all derive from that route [1][6]. No oral, intranasal, or other route has clinical-trial efficacy data behind it — the entire evidence base is subcutaneous, once daily. ## Why a short-lived peptide is dosed once daily The once-daily schedule is a pharmacodynamic decision, not a pharmacokinetic one. Native GHRH is destroyed by DPP-IV within minutes; tesamorelin's N-terminal cap blunts that, but plasma clearance is still rapid — about 1,060 L/h in population modeling [12]. What outlasts the peptide is the signal it triggers: growth hormone is released in pulses, and the IGF-1 that growth hormone drives from the liver stays elevated across the day [4]. So a once-daily pulse of tesamorelin produces a near-continuous downstream IGF-1 effect, which is the biological lever for visceral-fat reduction [1][4]. In the pivotal program, that once-daily 2 mg schedule sustained a roughly 18% visceral-fat reduction across 52 weeks [2]. The PK modeling also found the absorbed fraction rose about 13% by day 14 versus day 1, a small accumulation in exposure over the first two weeks [12]. None of this is a dosing instruction — it is the rationale investigators reported for the schedule they studied. ## What is the half-life of tesamorelin? Plasma exposure is short — population PK clearance is about 1,060 L/h, and secondary sources cite a terminal half-life near 26-38 minutes [12][5]. The downstream IGF-1 elevation persists across the dosing interval, which supports once-daily administration in the studies [4]. ## How long does tesamorelin stay in your system? The peptide clears from plasma rapidly, but its biological effect — raised IGF-1 — outlasts plasma levels [4]. In PK modeling, the absorbed fraction rose about 13% by day 14 versus day 1 [12]. So the molecule is gone quickly while its growth-signal effect lingers across the day. --- A trial console on a dark field — the tesamorelin record read newest panel first, the FDA-approved-for-HIV-lipodystrophy scope flagged before any number and the off-label edge held lit; no clinic at this console and nothing here dosed, dispensed, or sold.