Sermorelin is the synthetic 1 to 29 N-terminal fragment of endogenous human GHRH, with a half-life of approximately 10 to 20 minutes, dosed nightly by subcutaneous injection. This page covers what it is, a worked reconstitution example, typical research protocols, storage, and the most common follow-up questions.
Sermorelin is a synthetic fragment of growth hormone-releasing hormone (GHRH). It signals the pituitary gland to release the body's own growth hormone in natural pulses, preserving the pituitary axis. Sermorelin is FDA approved for pediatric growth hormone deficiency and is used off-label in adult longevity protocols. Half-life is short, around 10 to 20 minutes.
Sermorelin is a synthetic 29 amino acid peptide that reproduces the N-terminal 1 to 29 fragment of endogenous human growth hormone-releasing hormone (GHRH). The 1 to 29 fragment retains the full biological activity of the parent 44 amino acid GHRH and is the smallest sequence that still binds and activates the GHRH receptor on the anterior pituitary. The molecule is unmodified, meaning it does not carry the stabilizing substitutions or albumin-binding tails that distinguish later analogs such as Tesamorelin and CJC-1295.
Mechanistically, Sermorelin binds the GHRH receptor on pituitary somatotrophs and triggers a short, sharp pulse of endogenous GH release. The pulse pattern mimics what the body's own GHRH does, which is the appeal of the molecule: it preserves the natural pulsatile signaling without producing the sustained, non-pulsatile elevation associated with some longer-acting analogs.
Sermorelin was historically marketed in the United States under the brand name Geref for the diagnosis and treatment of pediatric growth hormone deficiency; the branded product was discontinued in 2008 for commercial reasons. The molecule remains available through compounding pharmacies and as a research chemical. It is not currently FDA-approved as a finished pharmaceutical product.
The worked example below uses a 5 mg vial and 2 mL of bacteriostatic water. Adjust the BAC water volume in the reconstitution calculator for different vial sizes.
| Input | Value | Notes |
|---|---|---|
| Vial size | 5 mg (5000 mcg) | Lyophilized powder |
| BAC water added | 2 mL | Bacteriostatic water with 0.9% benzyl alcohol |
| Resulting concentration | 2.5 mg / mL (2500 mcg / mL) | 5 mg divided by 2 mL |
| Common dose | 200 mcg | Once nightly |
| Volume to draw at 200 mcg | 0.08 mL | 200 mcg divided by 2500 mcg / mL |
| Units on 1 mL (100 unit) syringe | 8 units | 0.08 mL multiplied by 100 |
| Volume to draw at 300 mcg | 0.12 mL (12 units) | Higher single-dose protocol |
| Doses per vial at 200 mcg | 25 doses | 5000 mcg divided by 200 mcg |
The table below summarizes typical research and compounding dosing patterns. This is reference information for research contexts only and is not a recommendation for human use.
| Protocol | Per dose | Frequency | Cycle length |
|---|---|---|---|
| Low nightly | 200 mcg | Once nightly before bed | 12 to 24 weeks |
| Standard nightly | 300 mcg | Once nightly before bed | 12 to 24 weeks |
| Higher nightly | 500 mcg | Once nightly before bed | 12 weeks |
| 5 days on / 2 off | 300 mcg | Nightly, 5 days per week | 12 to 24 weeks |
Sermorelin has a very short plasma half-life of approximately 10 to 20 minutes. It is the unmodified 1 to 29 fragment of GHRH and is rapidly degraded by DPP-4 and cleared via renal filtration. The molecule does not carry stabilizing modifications.
The short half-life is what produces the single sharp GH pulse and what dictates the nightly dosing schedule. A dose given before bed amplifies the natural GH pulse that occurs during deep sleep. Daytime dosing produces a pulse but with smaller aggregate effects on IGF-1 due to background hormonal context. Some 5 days on / 2 days off protocols are used to limit any potential downregulation, although evidence for downregulation at typical nightly doses is limited.
Lyophilized Sermorelin is stable for months at 2 to 8 degrees Celsius and for years at -20 degrees Celsius. Keep the vial sealed and shielded from light.
Reconstituted Sermorelin is typically stable for 2 to 3 weeks when refrigerated at 2 to 8 degrees Celsius, kept upright, and shielded from light. Do not freeze. Discard if the solution becomes cloudy, discolored, or develops visible particulates.
Swirl gently to dissolve. Do not shake.
The stabilized GHRH analog with FDA approval.
Read reference →Another stabilized 1 to 29 analog, with or without DAC.
Read reference →Run your own vial size and BAC water volume through the calculator.
Open calculator →Sermorelin, Tesamorelin, and CJC-1295 side by side.
Read article →Peptide AI Stack Intelligence is free on iOS and Android. Log every dose, track IGF-1, watch sleep quality.