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US Peptide Guide

Last reviewed May 22, 2026·Editorial Board

Sermorelin (GHRH 1-29)

Also known as GHRH (1-29), GRF (1-29), Geref, Sermorelin acetate

Sermorelin is a synthetic 29-amino-acid peptide that corresponds to the first 29 residues of native human growth hormone-releasing hormone (GHRH). It is the shortest fragment of GHRH that retains full biological activity at the pituitary GHRH receptor.[1]

Tier 2 — Clinically StudiedWithdrawn(2008-12-02)Compounding: Category 1(2013-03-04)
Class
GHRH analog (1-29)
Sequence length
29 amino acids
Half-life
~11–12 min plasma
Route
Subcutaneous
Human RCTs
5+ (pediatric + elderly)
WADA status
Prohibited

What sermorelin is

Sermorelin acetate is a 29-residue synthetic peptide that mimics the active portion of endogenous GHRH. Unlike exogenous recombinant human growth hormone (somatropin), sermorelin acts upstream: it binds the GHRH receptor on pituitary somatotrophs and stimulates the pituitary to release its own growth hormone in physiologic pulses.[1] Because the downstream growth hormone signal still passes through normal negative feedback (rising IGF-1 suppresses further GH release), sermorelin cannot push GH levels arbitrarily high — a meaningful safety distinction from direct GH administration.

Sermorelin has the rare distinction of being a peptide with a complete US regulatory history. The branded version (Geref, EMD Serono) was FDA-approved in 1990 as a diagnostic for pituitary GH deficiency and again in 1997 for the treatment of idiopathic growth hormone deficiency in children. EMD Serono voluntarily discontinued both formulations in 2008. The FDA confirmed in a 2013 Federal Register notice that the withdrawal was NOT for reasons of safety or effectiveness — it was a commercial decision.[2]

Mechanism of action

Sermorelin binds the GHRH receptor (a Gs-coupled GPCR) on anterior pituitary somatotrophs, raising intracellular cAMP and triggering pulsatile growth hormone release. Released GH acts on the liver and peripheral tissues to drive IGF-1 production.[3]

The pharmacokinetic profile is short: plasma half-life is approximately 11–12 minutes, with biological effect on GH release lasting longer than the parent peptide remains in circulation.[1] This short half-life means that dosing typically targets nighttime administration to align with the body's natural overnight GH pulse.

Because the GH released is the patient's own pituitary GH (not exogenous), the normal feedback mechanisms remain intact. This is the principal mechanistic argument for sermorelin over direct somatropin in age-related GH decline: it preserves physiologic pulsatility and feedback regulation rather than overriding them.[4]

Human evidence

Sermorelin has a richer human dataset than most peptides in this database, with separate evidence in pediatric and elderly populations. Pediatric data underpinned the original Geref approval; elderly data informs the current age-related off-label use case.

Pediatric idiopathic short stature — RCT
Multiple children, 12-month treatment

Walker et al. (1994) reported that treatment with GHRH(1-29)NH2 in children with idiopathic short stature induced a sustained increase in growth velocity over 12 months of subcutaneous therapy. The signal was strong enough to support the subsequent FDA approval of Geref for pediatric idiopathic GH deficiency.

Sources:51
Aging men — placebo-controlled RCT
Older men, GHRH (1-29) twice daily

Corpas et al. (1992) found that twice-daily subcutaneous GHRH (1-29) administration in old men reversed the age-related decrease in serum GH and IGF-1 toward levels seen in young controls. IGF-1 elevation persisted for approximately two weeks after stopping treatment, suggesting pituitary reactivation rather than a pure injection-effect.

Sources:3
Aging men — single nightly injection
11 elderly men, 6 weeks

Vittone et al. (1997) gave 2 mg nightly subcutaneous GHRH (1-29) to 11 healthy non-obese men aged 64–76 with low baseline IGF-1. Nocturnal GH release and peak amplitude increased. Two of six muscle strength measures (upright row, shoulder press) and one endurance measure improved. The authors noted single nightly dosing appeared less effective than multiple daily dosing for elevating IGF-1.

Sources:6
Aging men and women — immune and endocrine effects
19 elderly subjects (10F, 9M), 16 weeks

Khorram et al. (1997) ran a single-blind placebo-controlled trial of [Nle27]GHRH(1-29)-NH2 (a stabilized sermorelin analog) at 10 μg/kg nightly for 16 weeks. T-cell responsiveness to PHA rose 50%, IL-2 receptor expression rose 70%, and IL-2 secretion rose 50%. Men gained ~1.26 kg lean body mass and showed improved insulin sensitivity; both sexes showed increased skin thickness.

Sources:4

The combined elderly dataset — Corpas, Vittone, Khorram — is the foundation of the modern off-label "age-related GH decline" use case. The findings are consistent in direction (GH and IGF-1 rise; small body composition improvements) but the trials are small (n=10–20) and short (6–16 weeks).

Marketed claims vs. published evidence

Marketed claims
  • Reverses biological aging
    anecdotal
  • Replacement for HGH
    anecdotal
  • Dramatic fat loss within weeks
    no data
  • Improves sleep architecture
    anecdotal
Published evidence
  • Raises nocturnal GH and IGF-1 in older adults[3]
    human RCT
  • Increases lean body mass modestly in older men[4]
    human RCT
  • Increases growth velocity in children with idiopathic GHD[5]
    human RCT
  • Activates T-cell function in elderly subjects[4]
    human RCT

The published human dataset supports: (1) GH/IGF-1 elevation, (2) modest lean body mass gains in older men, and (3) growth velocity gains in pediatric GHD. It does not support claims of dramatic fat loss, "biological age reversal," or equivalence to recombinant GH therapy.

Regulatory status

Sermorelin occupies an unusual regulatory position: it is the only major research peptide in this database that was previously FDA-approved as a finished drug product and then voluntarily withdrawn — without safety or efficacy concerns.[2]

Key points for prescribers and patients:

  • No FDA-approved finished product exists in 2026. All sermorelin currently dispensed in the United States is compounded by 503A or 503B pharmacies from bulk drug substance.
  • Compounding remained legal throughout the 2023–2026 BPC-157 / TB-500 reclassification events. Sermorelin was not on the 2023 Category 2 list that restricted BPC-157, TB-500, Thymosin Alpha-1, AOD-9604, and others. It was unaffected by the April 2026 Category 1 reversal because it had never been removed.
  • Sermorelin is on the WADA Prohibited List (S2) as a GH secretagogue.[7]

Safety considerations

The reported adverse event profile in the published RCTs is mild: injection site reactions, occasional flushing, and infrequent headache. Long-term safety beyond ~16 weeks of continuous administration has not been studied in adequately powered modern trials. The pulsatile, physiologically-regulated GH release that sermorelin produces is mechanistically lower-risk than exogenous somatropin, but this does not mean it is risk-free.

Dosing is not addressed on this page. Sermorelin dosing decisions belong with a licensed prescriber evaluating an individual patient's clinical context.

Frequently asked questions

Tesamorelin (Egrifta)peptideCJC-1295peptideIpamorelinpeptideGH secretagogueshub

Citations

  1. Prakash A, Goa KL. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs. 1999. PMID 18031173
  2. U.S. Food and Drug Administration. Determination That GEREF (Sermorelin Acetate) Injection Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness. Federal Register, 78 FR 14122. 2013. ↗ Source fda
  3. Corpas E, Harman SM, Piñeyro MA, Roberson R, Blackman MR. Growth hormone (GH)-releasing hormone-(1-29) twice daily reverses the decreased GH and insulin-like growth factor-I levels in old men. Journal of Clinical Endocrinology and Metabolism. 1992. PMID 1379256
  4. Khorram O, Yeung M, Vu L, Yen SS. Effects of [norleucine27]growth hormone-releasing hormone (GHRH) (1-29)-NH2 administration on the immune system of aging men and women. Journal of Clinical Endocrinology and Metabolism. 1997. PMID 9360512
  5. Walker RF, Codd EE, Barone FC, et al. Treatment with GHRH(1-29)NH2 in children with idiopathic short stature induces a sustained increase in growth velocity. Hormone Research. 1994. PMID 7955460
  6. Vittone J, Blackman MR, Busby-Whitehead J, et al. Effects of single nightly injections of growth hormone-releasing hormone (GHRH 1-29) in healthy elderly men. Metabolism: Clinical and Experimental. 1997. PMID 9005976
  7. World Anti-Doping Agency. The 2026 Prohibited List — S2 Peptide Hormones, Growth Factors, Related Substances and Mimetics. wada-ama.org. 2026. ↗ Source wada
Revision history
  • 2026-05-22Initial page. Five primary RCT citations (pediatric + elderly), Geref FDA history with 2013 Federal Register confirmation, WADA status.