Sermorelin Dosing and Reconstitution Explained

Sermorelin is given as a nightly subcutaneous injection — historically 30 mcg/kg in the FDA-approved pediatric therapy, and commonly 200–300 mcg in modern compounded protocols — and the number of syringe units you draw depends entirely on how much bacteriostatic water you used to reconstitute the vial. A 5 mg vial mixed with 2 mL of water becomes 25 mcg per unit, so a 200 mcg dose works out to 8 units on a U-100 insulin syringe.

TL;DR — key takeaways

• It works indirectly. Sermorelin is a 29-amino-acid fragment of growth hormone-releasing hormone (GHRH) that prompts your own pituitary to release growth hormone — it is not injected growth hormone.
• Dosed at night. Its half-life is only about 10–12 minutes, so it is given at bedtime to ride the body's natural overnight GH pulse.
• Units follow concentration. The same 200 mcg dose can be 8 units or 20 units depending on how much water you added — the drug amount never changes, only the dilution.
• Status matters. The branded FDA product (Geref) was withdrawn in 2008 for commercial reasons; today sermorelin is supplied only by compounding pharmacies, and wellness dosing is off-label and not FDA-established.

What sermorelin is and how it is dosed

Sermorelin acetate is a synthetic copy of the first 29 amino acids of human GHRH — the shortest fragment that keeps the full biological activity of the parent hormone. Rather than supplying growth hormone directly, it binds the GHRH receptor on the pituitary's somatotroph cells and stimulates them to make and release the body's own growth hormone, producing a pulse rather than a sustained flood.

Because circulating sermorelin is cleared within minutes, a single injection does not linger. That short window is why it has always been dosed once daily at bedtime: the aim is to reinforce the natural GH surge that occurs during early sleep. In the FDA-approved pediatric programme, the treatment dose was 30 mcg/kg (0.03 mg/kg) subcutaneously each night, while the separate diagnostic test used a single 1 mcg/kg intravenous dose to see whether the pituitary could respond. Modern compounded protocols for adults typically land in the 200–300 mcg nightly range — a fixed amount rather than a weight-based one — but that range comes from clinical and compounding practice, not from an FDA-approved label.

Sermorelin at a glance

The half-life and receptor facts are drawn from published pharmacokinetic and clinical studies; the compounded dose range reflects current practice and is not an FDA-approved instruction. Always follow the protocol your prescriber sets.

How this is calculated: the reconstitution math

Sermorelin arrives as a freeze-dried powder that you dissolve in bacteriostatic water before use. Two numbers decide everything you read on the syringe: the milligrams of peptide in the vial, and the millilitres of water you add. Divide the first by the second to get concentration in mg/mL. A U-100 insulin syringe holds 100 units in 1 mL, so each unit is one-hundredth of a millilitre. The clean shortcut: mcg per unit = mg/mL × 10. Once you know mcg per unit, your dose in units is simply your dose in mcg divided by that number. There is no drug-specific constant — the same arithmetic applies to any reconstituted peptide.

Dose-to-units reference chart

Nightly doses shown as units on a U-100 syringe, for a 5 mg vial reconstituted with two common water volumes. Confirm every figure against your own vial label.

Read across a single row and the units double when you switch from the 2 mL to the 5 mL mix — the dose is identical; only the dilution changed.

How water volume changes the units, visualised

The same 5 mg vial and the same 200 mcg dose, drawn at three different reconstitution volumes. Add more water and each unit carries less drug, so you draw more units for the same dose.

Honest caveats before you rely on any of this

The only FDA-approved sermorelin product, Geref, was discontinued in 2008 for commercial reasons rather than safety, so current supply comes from compounding pharmacies. Adult anti-aging and wellness dosing sits outside any approved label, and the long-term evidence base for that use is thin compared with the pediatric growth-hormone-deficiency data. Older clinical work also showed that in children, recombinant growth hormone drove faster catch-up growth than GHRH therapy did, which is part of why sermorelin never became a routine treatment. Treat the numbers here as arithmetic that helps you read a syringe accurately — not as a recommendation to use the compound, and not as medical advice. Dose, suitability, and monitoring are decisions for a licensed prescriber.

Frequently asked questions

Is sermorelin the same as injecting growth hormone?

No. Growth hormone is the hormone itself; sermorelin is a GHRH fragment that signals your pituitary to release its own growth hormone. The effect depends on a working pituitary, and the release is pulsatile rather than a steady exogenous level.

Why is it injected at bedtime?

Sermorelin clears from the blood within minutes, and the body's largest natural growth-hormone pulse happens during early sleep. Dosing at night lines the two up.

Does a bigger vial mean more units per dose?

Not by itself. Units depend on concentration — milligrams divided by the water you add. A 9 mg vial in 3 mL gives the same 30 mcg-per-unit strength as a 3 mg vial in 1 mL, so the same dose is the same number of units.

How should reconstituted sermorelin be stored?

Once mixed it is a liquid peptide and is kept refrigerated, protected from light, and used within the window your pharmacy specifies. Follow the discard date on your vial rather than a generic rule.

Related guides

• What peptide reconstitution actually means
• How much bacteriostatic water should I add?
• How to read units on an insulin syringe
• All guides

Skip the arithmetic and let the peptide reconstitution calculator convert your vial and dose to exact units.