EVIDENCE BOARD / 03
Sermorelin doses, routes, and half-life as studied
What was administered, to which population, by which route, in the published research — read as a record, never as a protocol to follow.
Before the details
This page reports the sermorelin doses that appear in published studies — the amounts researchers gave, to whom, and how. It is a description of the literature, not a dosing guide, and nothing here is a recommendation to self-administer. Two facts shape every entry. The peptide clears the blood fast — a half-life of about ten to twelve minutes [3] — yet a single dose keeps growth hormone elevated for roughly three hours [3]. And the route matters: injection under the skin was the workhorse in studies, while the nasal route managed only a few percent absorption [3]. The numbers below are study facts, attributed to their sources.
Doses studied in the literature
The doses studied in the literature span three research contexts. In the pediatric growth-hormone-deficiency efficacy study, the dose was 30 mcg/kg/day subcutaneously at bedtime, which raised first-year height velocity from ~4.1 to ~7-8 cm/year [1]. In aging research, healthy older men received 0.5 mg and 1 mg subcutaneously twice daily for 14 days, with the high dose restoring GH/IGF-1 toward young-adult levels [2].
In pharmacokinetic work, intravenous doses of 0.25-2 mcg/kg elicited growth-hormone release in 30 healthy men, with maximal release at 1-2 mcg/kg [3]. A single intravenous bolus of roughly 1 mcg/kg was also used historically as a diagnostic growth-hormone stimulation test to probe pituitary reserve. Each figure is a study parameter, not a personal dose.
Sermorelin half-life and pharmacokinetics
Sermorelin half-life and pharmacokinetics
Sermorelin half-life is short: on the order of ~10-12 minutes in plasma after intravenous administration, with GHRH(1-29) rapidly eliminated [3]. The apparent paradox — fast clearance, longer effect — resolves because a single dose still elevates serum growth hormone for about 3 hours [3]: the peptide triggers a pituitary pulse and then leaves, while the downstream growth-hormone signal persists.
That brevity is the engineering problem the whole analog field was built to solve. The native peptide's short life motivated longer-acting analogs — D-Ala2 substitution and the DAC (Drug Affinity Complex) albumin-binding technology behind CJC-1295 — and PEGylation strategies reviewed for GRF analogues describe further half-life-extension chemistry [11]. See sermorelin vs CJC-1295 for the native-versus-extended contrast.
Routes and formulation studied
Subcutaneous injection was the primary route across the efficacy and aging studies [1][2]. The intravenous route appears in diagnostic and pharmacokinetic work [3]. The intranasal route was tested historically and returned only ~3-5% bioavailability [3] — the data point most often cited when research-user communities criticize oral, sublingual, and troche "sermorelin" products as ineffective, since peptides are degraded in the gut and poorly absorbed across mucosa.
Formulation follows from the chemistry: lyophilized sermorelin acetate is reconstituted with sterile diluent and then typically refrigerated, because aqueous peptide solutions degrade. Compounded preparations are made under USP <797> sterile-compounding standards. Timing in studies leaned on bedtime administration to coincide with the natural nocturnal growth-hormone pulse during slow-wave sleep — a research-protocol rationale, described here as study design rather than instruction.
Why duration varied across studies
There is no single established course length, because study durations were set by endpoint. Acute pharmacokinetic and stimulation studies dosed once and measured growth hormone over hours [3]. The adult endocrine study dosed for 14 days to show sustained GH/IGF-1 change [2]. Pediatric growth studies ran for months to a year to capture height velocity [1].
The GHRH-analog cognition trial ran 20 weeks [6]. Any fixed adult duration — "three months," for instance — is therefore a research-design choice in a specific study, not a standard, and not a recommendation. The molecular weight (3357.9 Da) and identifiers (CAS 86168-78-7) sit in the full reference list alongside the studies these durations come from.