# Sermorelin Dosage in the Research Literature

> Sermorelin dosage in the published literature: pediatric GHD protocols at 30 mcg/kg, adult aging studies at ~14 mcg/kg bedtime, JAMA RCT at 1 mg twice daily. Half-life: ~4.3 minutes IV.

## Sermorelin daily dose ranges studied in literature

Sermorelin dosage in published research varies substantially by population and indication. The following doses appear in peer-reviewed trials and the original FDA-approved labeling:

- **Pediatric GH deficiency (Thorner 1996, Geref International Study Group, JCEM):** 30 mcg/kg subcutaneously at bedtime, daily. This was the FDA-approved Geref dose. In 110 GH-deficient children, this produced height velocity acceleration from 4.1 ± 0.9 cm/yr at baseline to 8.0 ± 1.5 cm/yr at 6 months; 74% of children responded favorably in year one [2].
- **Pediatric idiopathic short stature (Kirk 1994, Clinical Endocrinology):** 20 mcg/kg twice daily subcutaneous for 12 months in 18 pre-pubertal children; height velocity increased from 4.8 ± 0.9 to 7.2 ± 1.6 cm/yr (P=0.001) [3].
- **Pediatric radiation-induced GHD (Ogilvy-Stuart 1997, Clinical Endocrinology):** 15 mcg/kg twice daily subcutaneous for 12 months; height velocity improved from 3.3 ± 1.1 to 6.0 ± 1.5 cm/yr (P=0.004) in 9 prepubertal children [16].
- **Adult aging and body composition (Vitiello 2001, Dialogues in Clinical Neuroscience):** 14 mcg/kg (~1 mg) subcutaneously at bedtime daily for 5-6 months; produced ~35% IGF-1 elevation, ~5% lean mass increase, and visceral fat reduction [4].
- **HIV lipodystrophy (Koutkia 2004, JAMA):** 1 mg subcutaneously twice daily for 12 weeks; produced significant IGF-1 elevation and body composition improvements versus placebo [10].
- **Combination secretagogue protocol (Sigalos 2017, American Journal of Men's Health):** 100 mcg sermorelin three times daily subcutaneous (with GHRP-6 and GHRP-2); raised IGF-1 from 159.5 to 239.0 ng/mL (P<0.0001) over a mean 134-day treatment period [9].

These are documented research-population doses, not recommendations for any individual.

## Sermorelin Half-Life and Pharmacokinetics

Native GHRH(1-29)-NH2 plasma half-life is approximately 4.3 ± 1.4 minutes in healthy men via intravenous administration (Soule et al. 1994, Journal of Clinical Endocrinology & Metabolism) [7]. The metabolic clearance rate of native GHRH-(1-29)-NH2 is 39.7 ± 3.9 mL/kg·min. N-terminal enzymatic cleavage is the primary degradation pathway, producing the GRF3-29 metabolite [7].

Subcutaneous bioavailability of sermorelin is less than 4% [14]. Following subcutaneous injection, the compound's biological half-life (GH pulse duration) extends beyond the plasma half-life due to absorption kinetics from the injection depot — the induced GH pulse peaks at 30-60 minutes and returns to baseline within 3-4 hours in pharmacokinetic studies.

## Sermorelin half-life and clearance

Sermorelin has a very short plasma half-life of approximately 4.3 minutes via IV (Soule 1994) [7]; subcutaneous half-life is approximately 8 minutes [14]. The GH pulse induced by sermorelin peaks at 30-60 minutes and returns to baseline within 3-4 hours. The compound itself is cleared within minutes; the downstream GH pulse lasts approximately 3-4 hours, with the biological effects of elevated IGF-1 persisting on a longer timescale determined by IGF-1 half-life (~12-15 hours in serum).

## Evening dosing rationale in sermorelin research

Endogenous GH secretion is highest during slow-wave sleep; evening sermorelin administration is designed to amplify the physiological nocturnal GH pulse [8]. The Kerkhofs 1993 study (American Journal of Physiology) provided direct mechanistic support: an intravenous GHRH bolus (0.3 mcg/kg) administered during late sleep in healthy young men produced a nearly 10-fold increase in slow-wave sleep in the third REM period [8]. All major adult therapeutic sermorelin trials used bedtime dosing [2][4][10].

## Sermorelin injection site protocols in research

Subcutaneous injection into abdominal, thigh, or deltoid adipose tissue is the route used in clinical trials [4][10]. The pediatric GHD FDA-approved protocol and all major adult studies used subcutaneous injection exclusively as the primary clinical route. Intravenous administration was used in pharmacokinetic characterization studies but is not a route associated with therapeutic protocols [7][8].

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A bright, plain-spoken digest of the peer-reviewed Sermorelin record — GHRH(1-29) literature sorted and cited, no clinic behind the name.