# Sermorelin Dosage in the Research Literature | Doctor Sermorelin > Sermorelin dosage as studied in clinical trials: pediatric 30 mcg/kg/day, adult 1–2 mg nightly, combination protocols 100 mcg three times daily. Half-life, routes, and timing — cited. Doses used in peer-reviewed protocols, organized by population and route. Plasma half-life and timing rationale included. Not a prescribing guide — a literature index. ## > DOSE LITERATURE / PLAIN READ This page collects the doses, routes, and timing protocols from published sermorelin research. These are parameters from specific studies in specific populations — not prescribing guidance or dosing recommendations. The short version: pediatric GH-deficiency trials used 30 micrograms per kilogram per day, injected under the skin at bedtime. Elderly adult studies used roughly 1–2 milligrams nightly. The combination secretagogue protocol in Sigalos et al. (2017) used 100 micrograms three times daily alongside two GHRP-class compounds. All trial protocols specified subcutaneous injection; intravenous dosing was used only for pharmacokinetic characterization. Plasma half-life is approximately 4 minutes after intravenous administration, but GH pulse elevation persists for roughly three hours — the peptide triggers the response and clears rapidly. The rationale for pre-sleep timing and its mechanistic basis are explained in the timing section below. ## Daily Sermorelin Doses Used in Clinical Research The sermorelin dosage literature spans pediatric GHD trials, adult elderly cohorts, and combination GH secretagogue protocols. All figures below are from published studies — not recommendations. **Pediatric GH deficiency:** 30 mcg/kg/day subcutaneous at bedtime — Geref International Study Group (1996), n=110 prepubertal children [1]. 20 mcg/kg twice daily subcutaneous — Kirk et al. (1994), idiopathic short stature children [2]. **Adult (elderly cohort — GH-axis decline):** Approximately 14 mcg/kg (~1 mg) subcutaneous at bedtime for 6 months — Merriam et al., 2011 program [6]. 2 mg subcutaneous nightly for 6 weeks — Vittone et al., 1997 [5]. **Combination GH secretagogue protocol:** 100 mcg sermorelin + 100 mcg GHRP-6 + 100 mcg GHRP-2 subcutaneous three times daily — Sigalos et al. (2017), hypogonadal men, n=105, mean 134-day course [12]. **Acute GH stimulation testing (IV, pharmacodynamic):** 0.25–2 mcg/kg intravenous — GH release dose-dependently elicited; maximal mean GH peaks at 1–2 mcg/kg IV [3]. How much sermorelin per day? Pediatric GHD trials used 30 mcg/kg/day subcutaneously. Adult studies used 1–2 mg nightly. Combination protocols used 100 mcg three times daily. These figures represent doses used in specific research populations — they are not generalized prescribing guidance. ## Sermorelin Study Duration: What Clinical Trials Used Trial durations in the published literature: - Pediatric GHD (Geref International, 1996): 12 months; height velocity measured at 6 months and 12 months [1]. - Idiopathic short stature (Kirk et al., 1994): 12 months continuous; catch-down growth observed 6 months post-cessation [2]. - Elderly nocturnal injection (Vittone et al., 1997): 6 weeks [5]. - Elderly 6-month program (Merriam et al., 2011): 6 months; IGF-1, body composition, and sleep endpoints [6]. - Cognitive function (Vitiello et al., 2006): 6 months [7]. - Combination secretagogue (Sigalos et al., 2017): mean 134 days (~4.5 months) [12]. - Tesamorelin analog RCT for cognition (Baker et al., 2012): 20 weeks [11]. Is 3 months of sermorelin enough? Published trials measured IGF-1 changes beginning at 6 weeks and body composition shifts at 3–6 months. Effects in some studies began appearing at 3 months; body-composition data typically required 6 months. No published trial specifically tested a 3-month endpoint as a study terminus for adult body composition. ## Sermorelin Injection Routes in Research Protocols Routes studied in published protocols: - **Subcutaneous:** Predominant route in clinical trials. Geref prescribing information specified subcutaneous injection at bedtime. Injection sites used in published protocols: abdomen, thigh. - **Intravenous:** Used in pharmacokinetic characterization and acute GH stimulation studies [3, 4]. - **Intranasal:** Studied; bioavailability only 3–5% [3]. Not a viable research administration route. Where to inject sermorelin? Published protocols used subcutaneous injection at the abdomen or thigh. The Geref prescribing information specified subcutaneous administration at bedtime. Intravenous route is limited to pharmacokinetic or stimulation-testing contexts in research settings. Intranasal bioavailability at 3–5% makes that route pharmacokinetically nonviable [3]. ## Sermorelin Half-Life and Pharmacokinetics Plasma half-life of native GHRH(1-29)-NH2 under constant IV infusion: approximately 4.3 ± 1.4 minutes in healthy men; metabolic clearance rate 39.7 ± 3.9 mL/kg·min [4]. D-Ala2 substitution (as in certain longer-acting analogs) extends half-life to approximately 6.7 minutes and approximately halves metabolic clearance rate [4]. Following a 500 mcg subcutaneous dose in human volunteers: intact sermorelin was undetectable in plasma samples. Primary metabolite (GRF3-29) was detectable at 30 minutes post-injection and absent by 90 minutes [17]. Detection of sermorelin in human plasma is markedly more challenging than in rat models — in rats, the detection window is 2–8 hours [17]. Sermorelin half-life summary: plasma half-life approximately 4–10 minutes in humans. The peptide is rapidly degraded by dipeptidyl peptidase IV (DPP-IV) cleavage at the N-terminus. Despite rapid plasma clearance, GH elevation is detectable within 30–60 minutes of subcutaneous injection and GH elevation persists for approximately 3 hours [3]. The mechanistic explanation: the peptide does not need to stay in plasma to sustain the GH pulse — it triggers the pituitary somatotroph response and clears; the GH pulse itself then unfolds on its own timeline. ## Sermorelin Onset of Action: Research Timelines Acute timeline (pharmacodynamic studies): - GH pulse elevation: detectable within 30–60 minutes of subcutaneous injection [3]. - GH elevation sustained: approximately 3 hours post-dose [3]. - Primary metabolite (GRF3-29): detectable 30 minutes post-500 mcg SC, cleared by 90 minutes [17]. Clinical timeline (trial endpoints): - IGF-1 changes: begin appearing within weeks; statistically significant changes reported at 6 weeks (Vittone 1997) and confirmed at 6 months (Merriam 2011) [5, 6]. - Body composition: shifts documented over 3–6 months in the Merriam program [6]. - Cognitive performance: improvements documented at 6 months in Vitiello 2006 and at 20 weeks in Baker 2012 [7, 11]. - Height velocity: significant increase documented by the 6-month measurement in the Geref pediatric trial [1]. How long does it take for sermorelin to work? Acute GH pulse: 30–60 minutes. IGF-1 rise: weeks. Body composition and height velocity: 3–6 months in published trial timelines. ## Sermorelin Administration Timing in Research Protocols Published protocols consistently specify pre-sleep administration. The mechanistic rationale: 1. **Dominant nocturnal GH pulse:** The largest daily GH pulse in adults occurs at the onset of slow-wave sleep (SWS / N3). Administering GHRH immediately before sleep positions sermorelin's receptor-binding window to coincide with this endogenous amplitude peak. 2. **Somatostatin nadir:** Somatostatin tone is lowest at sleep onset — reducing the inhibitory gate and maximizing GHRH-R responsiveness. 3. **Insulin clearance:** Food-stimulated insulin elevation blunts GH release; pre-sleep administration in a fasted state minimizes insulin interference with the GH pulse. Sermorelin administration timing per the Geref prescribing information and subsequent published adult protocols: subcutaneous injection at bedtime. Sigalos et al.'s combination protocol used three-times-daily dosing [12] — this protocol did not restrict to bedtime and was designed to achieve sustained IGF-1 elevation across the day via repeated pulse stimulation. ## Sermorelin Stability and Storage in Research Settings Lyophilized sermorelin acetate powder: stable at room temperature in sealed vials. Reconstituted peptide solution: requires refrigeration. Study protocols specify storage and use periods. In vivo stability: the peptide undergoes rapid N-terminal enzymatic degradation via dipeptidyl peptidase IV (DPP-IV) cleavage in vivo [4]. This is why intranasal delivery is not pharmacokinetically viable — gastrointestinal and nasal mucosal proteolysis degrade the peptide before meaningful absorption can occur [3]. Does sermorelin need to be refrigerated? Lyophilized powder: room temperature storage is acceptable per standard peptide handling protocols. Reconstituted solution: refrigerated and used within the period specified in the study protocol (typically 7–14 days per compounding pharmacy labeling conventions). --- Telemetry from the published record. Not a clinic, not a prescription, not a vendor.