What is Sermorelin? A plain-English explainer
A lab-made copy of the shortest fully active fragment of human growth-hormone-releasing hormone.
Sermorelin is a synthetic peptide — a chain of 29 amino acids that copies the first 29 amino acids of human growth-hormone-releasing hormone (GHRH), the shortest fragment of that hormone known to remain fully active at its receptor. It has a genuine FDA approval history under the brand name Geref, though that branded product is no longer marketed.
That one paragraph is the whole definition. The rest of this page unpacks it at two levels — plain English, then a little deeper — and shows how the reconstitution math works, because Sermorelin ships as a dried powder that has to be mixed and measured before anything else.
Sermorelin in plain English
Sermorelin is 29 amino acids long, which puts it firmly in peptide territory.
Your own pituitary gland responds to a natural hormone called growth-hormone-releasing hormone, or GHRH. Researchers found that only the first 29 amino acids of GHRH are needed for it to bind and act at its receptor — the rest of the molecule can be trimmed away without losing that activity. That 29-amino-acid fragment, synthesised in the lab, is Sermorelin. So when you see the name, read it as: a lab-made copy of the working end of a hormone your body already produces, nothing more mysterious than that.
It usually arrives as a small glass vial of white powder — Sermorelin acetate. The powder is the peptide with the water removed (freeze-dried, or “lyophilised”) so it stays stable in storage. On its own the powder can’t be measured into a syringe — there’s no volume to draw. That’s why the next step, reconstitution, exists.
The science, a little deeper
A few specifics that the plain-English version glosses over:
- It’s a defined sequence, not a mixture. Sermorelin is a single, known 29-amino-acid sequence — GHRH(1-29) — supplied as an acetate salt. That’s what makes it a peptide in the chemical sense rather than an extract.
- It’s supplied lyophilised. Removing the water gives the powder a long shelf life; adding a measured liquid back (reconstitution) is what turns it into an injectable solution with a known strength.
- Its regulatory history is unusually well documented. The FDA approved a Sermorelin acetate injection in 1990 for diagnostic use and then approved the branded product Geref in 1997 for treating growth hormone deficiency in children. The manufacturer discontinued Geref in 2008 for commercial reasons — the FDA’s own records confirm this was not a withdrawal for safety or effectiveness. There is currently no FDA-approved branded Sermorelin product on the market; supply today comes through compounding pharmacies, where individual compounded batches are not themselves FDA-approved drugs.
If you want the classification in one line: Sermorelin is a synthetic GHRH(1-29) analog, 29 amino acids, supplied as a freeze-dried acetate powder for reconstitution.
How reconstitution works for Sermorelin
Reconstitution is just dissolving the powder in a known volume of liquid so you have a concentration — milligrams of peptide per millilitre of solution. Once the concentration is fixed, the volume you draw for any target dose is simple arithmetic:
- Concentration = vial amount (mg) ÷ diluent volume (mL)
- Draw volume = target dose ÷ concentration
- Syringe units = draw volume (mL) × the units-per-mL of your syringe
The numbers all come from your own vial label and your prescription — the peptide amount printed on the vial, the volume of bacteriostatic water you add, and the dose you were told to use. The separate Amidra web calculator runs exactly those three steps and shows the formula at each one, so you can check it by hand. It never fills in a dose for you.
What Amidra does — and doesn’t — do here
Amidra is a tracking and education tool. It converts the values you enter and helps you keep a protocol organised; it does not recommend a dose, a compound, or a schedule, and it takes no position on whether anyone should use Sermorelin. Those decisions belong with a qualified healthcare professional. The information above is definitional — what the compound is — not medical advice.