Sermorelin dosage in the research: routes, half-life, and forms

The short version

This is a plain-English look at sermorelin dosage as it appears in the studies — what researchers gave, to whom, and how — not a how-to. We don't tell anyone what to take. We describe what was administered in published research and what the numbers mean.

The quick facts: sermorelin's parent peptide has been given mostly as a shot under the skin (subcutaneous) ^[2], it clears the body fast — a plasma half-life of only about 10-12 minutes — yet a single dose lifts growth hormone for roughly three hours ^[3]. That short half-life is exactly why scientists later built longer-acting cousins. Below: the routes studied, the half-life, why night-time timing comes up, and why pills are doubted.

Sermorelin dosage: what was given in studies

In the research record, the sermorelin dosage amounts vary by purpose. The pediatric growth study used roughly 30 mcg/kg/day subcutaneously at bedtime in growth-hormone-deficient children ^[1]. The aging study in older men used 0.5 mg and 1 mg subcutaneously twice daily for 14 days, and the higher dose is the one that reversed the age-related GH/IGF-1 decline ^[2]. Pharmacokinetic work in healthy men gave intravenous doses of 0.25 to 2 mcg/kg, with GH release seen even at the lowest amount and maximal release around 1-2 mcg/kg ^[3]. Historically, a single intravenous dose (commonly about 1 mcg/kg) was used as a diagnostic test of the pituitary's GH reserve ^[3]. These are study parameters, attributed to species and route — not a protocol for any person.

Sermorelin injection

The sermorelin injection route — subcutaneous, meaning a small shot into the fat just under the skin — is the primary route used across the human studies, including the older-men aging trial and the pediatric growth trial ^[1][2]. Intravenous (into a vein) dosing appears mainly in pharmacokinetic and diagnostic studies ^[3]. The peptide comes as a freeze-dried (lyophilized) powder that is mixed with sterile liquid before use, because peptides in water degrade over time; once mixed, it's typically refrigerated ^[3]. Compounded preparations are made under formal sterile-compounding standards. The injection route exists because the molecule needs to reach the bloodstream intact — which is the same reason the next section is skeptical of swallowed forms.

Sermorelin tablets

On sermorelin tablets (and sublingual drops or troches): the research gives a clear reason for doubt. Peptides like sermorelin are broken down by digestion in the gut, and even the nasal route — which skips the gut entirely — delivered only about 3-5% of the dose into the bloodstream in a pharmacokinetic study ^[3]. Forms you swallow or hold under the tongue face an even steeper absorption problem, which is why oral and sublingual "sermorelin" products are widely criticized as ineffective in research-user communities. The studies that produced sermorelin's measurable effects used injection, not pills ^[1][2][3]. This is an evidence note, not a purchasing or usage recommendation.

Half-life and why timing comes up

Sermorelin's plasma half-life is short — on the order of about 10-12 minutes after an intravenous dose; the peptide is cleared quickly ^[3]. Even so, one dose keeps growth hormone elevated for roughly three hours ^[3]. Because the body's biggest natural growth-hormone pulse happens during deep sleep, research and clinical discussion often pair GHRH-peptide timing with bedtime so an induced pulse rides alongside the natural one — the pediatric study, for instance, dosed at bedtime ^[1]. That short half-life is also the engineering problem that motivated longer-acting analogs: chemists added a D-Ala2 substitution and albumin-binding (DAC) technology to build the longer-lasting cousins, the most familiar being CJC-1295 with DAC ^[3].