# Sermorelin Dosage in Research: Routes, Half-Life, and Study Protocols > Sermorelin dosage as documented in studies: subcutaneous and intravenous research doses, the ~10-12 minute plasma half-life, bedtime administration, and sermorelin acetate's compounded form. Research context only. The doses, routes, and timing used in published studies, plus the short plasma half-life that shapes them. This describes study protocols, not a personal dosing recommendation. ## Before the details Everything here is research context — what was given to whom, at what dose, by which route, in published studies. It is not instructions and not a recommendation; sermorelin dosage on this page is reported, not prescribed. The one-line summary: studies used injections under the skin (subcutaneous), often at bedtime to match the body's natural overnight growth-hormone burst, and the molecule clears the blood fast — the [sermorelin half-life](/dosage) is roughly 10-12 minutes — even though a single dose keeps growth hormone raised for about three hours [3]. Below, the [sermorelin doses studied](/dosage) are organized by population and purpose. ## Sermorelin doses studied Across the literature, the doses are population- and purpose-specific — there is no single "sermorelin dose," only doses tied to a study's aim. The pediatric GH-deficiency efficacy study used 30 mcg/kg/day subcutaneously at bedtime [1]. Aging research in older men used 0.5 mg and 1 mg subcutaneously twice daily for 14 days, and only the higher dose fully reversed the age-related GH/IGF-1 decline [2]. Pharmacokinetic work in healthy men used intravenous doses of 0.25-2 mcg/kg, which elicited GH release, with maximal release at 1-2 mcg/kg [3]. Historically, a single intravenous bolus (commonly around 1 mcg/kg) was used diagnostically to test pituitary GH reserve. The cross-route dose ratios are documented: the [Nle27]GHRH(1-29)-NH2 analog required roughly tenfold higher subcutaneous and thirtyfold higher intranasal doses than intravenous to achieve comparable GH stimulation, without adverse effect [14]. That route penalty is why subcutaneous injection became the primary research route — it is the practical compromise between the efficient intravenous route and the poorly absorbed intranasal one. None of this is a protocol to follow; it is a record of what was administered, to whom, and how. ## Sermorelin half-life and how long it stays in your system Sermorelin has a short plasma half-life on the order of ~10-12 minutes after intravenous administration; GHRH(1-29) is rapidly eliminated, yet a single dose keeps serum GH elevated for roughly 3 hours [3]. That combination — fast clearance, longer biological effect — is characteristic of a secretagogue that triggers a downstream pulse rather than circulating as the active hormone itself. In plain terms, the molecule does its job by pulling a trigger and then leaving; the growth hormone it released lingers far longer than the trigger does. The peptide's brevity is precisely why longer-acting GHRH analogs were developed: structural changes such as a D-Ala2 substitution and serum-albumin-binding (DAC) chemistry extend duration well beyond the native fragment, reducing clearance [11]. By contrast, intranasal GHRH(1-29) bioavailability was only ~3-5%, which limited that route and underlies the common criticism that nasal, oral, and sublingual "sermorelin" formats are poorly absorbed [3]. The injectable subcutaneous route remains the one with a research record behind it. ## Why bedtime administration is studied Endogenous GH is released in pulses, with the largest surge during early slow-wave sleep — the deepest stage of the night. Study protocols therefore used bedtime subcutaneous administration to coincide with that natural nocturnal pulse rather than fight it: the pediatric efficacy trial dosed at bedtime [1], and single nightly GHRH(1-29) injections in healthy elderly men were studied specifically to examine whether bedtime dosing restores nocturnal GH/IGF-1 output [12]. The logic is alignment — adding a GHRH signal when the somatotroph is already primed to fire. This is a description of when studies dosed, not a recommendation about timing for any individual. ## Routes studied, and why some formats are criticized Three routes appear in the research: subcutaneous injection (the primary research route), intravenous (used in diagnostic and pharmacokinetic studies), and intranasal (a historical pharmacokinetic route). The route hierarchy is set by absorption. Intravenous is most efficient; subcutaneous required roughly tenfold higher doses than intravenous to match GH stimulation, and intranasal roughly thirtyfold higher — yet all three produced dose-responsive GH release without adverse effect in healthy men [14]. Intranasal bioavailability for GHRH(1-29) was only about 3-5% [3]. That low mucosal absorption is the documented basis for a common criticism in research-user discussions: oral, sublingual, and troche "sermorelin" formats are widely regarded as ineffective, because peptides are degraded in the gut and poorly absorbed across mucosa. The studies that demonstrated activity used injection. ## Sermorelin acetate: the compounded form The compounded material is **sermorelin acetate**, the amidated acetate salt of GHRH(1-29) (acetate CAS 114466-38-5; PubChem CID 16132412). It is supplied as a lyophilized (freeze-dried) powder because aqueous peptide solutions degrade over time; it is reconstituted with sterile diluent and then typically refrigerated, and the reconstituted solution has a limited shelf life. Compounded preparations are prepared under USP sterile-compounding standards. Under FDA's interim Section 503A policy, sermorelin is treated as a long-standing Category 1 bulk drug substance (final guidance January 2025), and FDA does not intend enforcement action against Category 1 compounding. That status is distinct from other GH-axis peptides reviewed by the Pharmacy Compounding Advisory Committee, and the two situations should not be conflated. This is context drawn from the regulatory record, not a statement about any product's availability, price, or source — and the material these pages discuss is research-grade, not a compounded prescription. ## What these dose figures have in common Read together, the research doses share a logic worth stating plainly. They are anchored to the body's own GH rhythm — bedtime administration to meet the nocturnal pulse [1][12] — and to a short-acting molecule whose effect is measured in the GH it releases, not in its own blood levels [3]. They differ by population and purpose: a weight-based pediatric efficacy dose [1], a fixed milligram dose twice daily in aging research [2], a microgram-per-kilogram bolus in pharmacokinetic and diagnostic work [3]. None of these is a template for an individual, and none should be read as one. The figures are reported here so the research record is legible, not so it can be followed. Any decision about a GH-axis intervention belongs with a qualified clinician who can weigh an individual's situation — a role this editorial digest does not occupy and does not attempt to fill. --- The sermorelin record filed cell by cell on a research board — every GH and IGF-1 figure carried back to its study, the body-composition evidence marked as tesamorelin where it belongs, and the empty long-term-safety cell left openly unfilled; no clinic behind the board and nothing here dosed, dispensed, or sold.