GHRH(1-29) analog · formerly FDA-approved (Geref, withdrawn 2008 for commercial reasons)

Sermorelin (Geref)

Historically approved for: pediatric growth hormone deficiency (Geref, 1997 — commercially withdrawn 2008). Currently: compounded use only.

Sermorelin acetate is a synthetic 29-amino-acid GHRH analog representing the 1–29 fragment of endogenous human GHRH — generally regarded as the shortest fully functional fragment. It was FDA-approved as Geref in 1997 for pediatric growth hormone deficiency and voluntarily withdrawn from the market in 2008 by EMD Serono for commercial, not safety, reasons. The FDA formally confirmed this distinction in 2013, which is why compounding pharmacies continue to produce sermorelin today.

Class
GHRH(1-29) analog
Structure
29-amino-acid polypeptide[1]
Original FDA approval
1997 (Geref, EMD Serono) — pediatric GH deficiency[1]
Current status
Geref commercially discontinued 2008 · compounded available[2]
Reason for withdrawal
Commercial (not safety/efficacy), per FDA 2013 determination[2]
Plasma half-life
~11–12 minutes (IV or SC)[3]
Clearance (adults)
2.4–2.8 L/min[3]
GH pulse timing
Peak 30–60 min post-dose · elevated several hours[3]
Educational reference only. Sermorelin is dispensed today primarily through compounding pharmacies with a prescription. This page summarizes the regulatory record and published pharmacology; it does not recommend a dose, an indication, or an acquisition channel. Consult a qualified healthcare professional for medical decisions.

Last reviewed April 24, 2026 by the Enhanced Health Editorial Team. See the editorial policy.

What sermorelin is

Sermorelin acetate is a synthetic 29-amino-acid polypeptide representing the 1–29 fragment of endogenous human growth hormone-releasing hormone (GHRH). Native GHRH is a 44-amino-acid peptide (GHRH 1–44). The 1–29 fragment is generally regarded in the literature as the shortest fully functional portion of the molecule — retaining the ability to bind and activate the GHRH receptor on pituitary somatotrophs and elicit growth hormone release.[1]

Mechanism

Sermorelin binds the GHRH receptor (GHRHR) on anterior pituitary somatotrophs and mimics the effects of full-length GHRH — stimulating growth hormone release through the body's own signaling pathway. Critically, because sermorelin works upstream of GH and is subject to the same negative-feedback modulation by somatostatin and IGF-1 that regulates native GHRH, the resulting GH release is pulsatile and self-limiting.[3]

This contrasts pharmacologically with exogenous recombinant GH (rhGH), which bypasses the pituitary feedback loop entirely and produces non-physiologic sustained GH levels. GHRH analogs like sermorelin, tesamorelin, and CJC-1295 share this "work with the natural feedback" property.

Regulatory history

  • 1997: Sermorelin acetate approved by the FDA as Geref (manufactured by EMD Serono) for the treatment of children with growth hormone deficiency or growth failure.[1]
  • 2008: EMD Serono voluntarily discontinued production of Geref. The reason given was commercial — not safety or efficacy.[2]
  • 2013: The FDA published a Federal Register determination formally confirming that Geref (sermorelin acetate) injection, at the previously approved strengths, was not withdrawn from sale for reasons of safety or effectiveness.[2] This determination has a specific regulatory consequence: drugs withdrawn for safety/efficacy reasons cannot be compounded by 503A pharmacies, while drugs withdrawn for commercial reasons generally can be. The 2013 FDA determination is therefore the legal basis under which compounded sermorelin continues to be produced today.
  • Today: Sermorelin is not sold as an FDA-approved commercial product in the U.S. It is dispensed through compounding pharmacies with a prescription.

Pharmacokinetics

  • Plasma half-life. Approximately 11–12 minutes after intravenous or subcutaneous administration.[3]
  • Clearance. 2.4–2.8 L/min in adults — rapid clearance consistent with a short-half-life peptide.[3]
  • GH pulse timing. The GH pulse triggered by a single sermorelin dose typically peaks within 30–60 minutes and remains elevated above baseline for several hours. The pharmacodynamic effect therefore outlasts the pharmacokinetic exposure — a common pattern for GHRH-class compounds.[3]
  • Downstream. IGF-1 rises over days with repeated dosing, reflecting cumulative GH exposure through the pituitary axis.

Storage and handling

  • Lyophilized powder. Store sealed per compounding-pharmacy or supplier instructions — typically refrigerated at 2–8 °C or frozen at −20 °C.
  • After reconstitution. Refrigerate at 2–8 °C. Bacteriostatic water (0.9% benzyl alcohol) for multi-draw use; sterile water for single-draw. Compounding pharmacies set their own beyond-use date on dispensed product.
  • Handling. Swirl — do not shake. Avoid freeze–thaw and vigorous agitation. Discard cloudy or discolored solutions.

Reconstitution math

Math only — no dose recommendation. The concentration after reconstitution determines how many insulin-syringe units equal a given mcg or mg amount.

Example 1 · 3 mg vial + 3 mL bac water concentration = 3 mg / 3 mL = 1 mg/mL = 1000 mcg/mL
1 unit = 0.01 mL = 10 mcg
→ 100 mcg = 10 units
→ 200 mcg = 20 units
→ 500 mcg = 50 units
→ 1 mg = 100 units (full syringe)
Example 2 · 3 mg vial + 1.5 mL bac water concentration = 3 mg / 1.5 mL = 2 mg/mL = 2000 mcg/mL
1 unit = 0.01 mL = 20 mcg
→ 100 mcg = 5 units
→ 200 mcg = 10 units
→ 500 mcg = 25 units
→ 1 mg = 50 units
→ 1.5 mg = 75 units
Example 3 · 15 mg vial + 3 mL bac water concentration = 15 mg / 3 mL = 5 mg/mL = 5000 mcg/mL
1 unit = 0.01 mL = 50 mcg
→ 100 mcg = 2 units
→ 500 mcg = 10 units
→ 1 mg = 20 units
→ 5 mg = 100 units (full syringe)

Frequently asked questions

What is sermorelin?

Synthetic GHRH(1-29) — the 29-AA fragment of endogenous GHRH. Binds pituitary GHRH receptor to trigger pulsatile GH release.[1]

Is it FDA-approved?

Was approved as Geref in 1997. Voluntarily withdrawn 2008 for commercial reasons. FDA confirmed 2013 that withdrawal was NOT for safety/efficacy — which is why compounded sermorelin is legally available today.[1][2]

Why was it withdrawn?

EMD Serono chose to stop production. Not a safety or efficacy problem — commercial decision, formally confirmed by FDA in 2013.[2]

What's the half-life?

~11–12 minutes. Rapid clearance (2.4–2.8 L/min in adults). GH pulse peaks 30–60 min, elevated several hours.[3]

How does it work?

GHRH receptor agonist on pituitary somatotrophs. Pulsatile GH release through the natural feedback loop — not exogenous GH replacement.[3]

How do I reconstitute a vial?

Typical: 3 mg + 3 mL bac water = 1 mg/mL → 1 unit = 10 mcg; 100 mcg = 10 units. Follow the compounding-pharmacy instructions on your specific product.

Primary references

  1. Wikipedia contributors. Sermorelin. Overview of structure, mechanism, and original 1997 FDA approval. en.wikipedia.org/wiki/Sermorelin
  2. U.S. Food and Drug Administration. Determination That GEREF (Sermorelin Acetate) Injection, 0.5 mg base/vial and 1.0 mg base/vial, and GEREF Injection, 0.05 mg base/amp, Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness. Federal Register, 4 March 2013. federalregister.gov — FDA 2013 determination
  3. Ghigo E, Boghen M, Casanueva FF, Dieguez C (eds). Growth Hormone Secretagogues (GHRHs and GHRPs). Review context on sermorelin pharmacokinetics, including 11–12 minute half-life and 2.4–2.8 L/min clearance in adults. sciencedirect.com
  4. Ishida J, Saitoh M, Springer J, et al. Growth hormone secretagogues: history, mechanism of action, and clinical development. JCSM Rapid Communications, 2020. Wiley Online Library

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