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[GH peptides · Comparison]

Ipamorelin vs sermorelin: how do they differ?

Mechanism · Half-life · Approval history

Short answer: They raise growth hormone through different receptors. Ipamorelin mimics ghrelin at the growth hormone secretagogue receptor;1 sermorelin is the first 29 amino acids of GHRH and acts on the GHRH receptor. Sermorelin was FDA approved as Geref, then discontinued, not for safety reasons.2 Ipamorelin has never been approved. Both are short-acting.

How do ipamorelin and sermorelin compare side by side?

From published human studies and FDA records. Neither has a current US label.
IpamorelinSermorelin
MechanismGhrelin receptor (GHS-R) agonist; selective GH release in animal studies1GHRH analog (GHRH 1-29); acts on the GHRH receptor
Approval statusNever FDA approvedApproved as Geref (diagnostic 1990; pediatric GH deficiency 1997); discontinued 2008; FDA found it was not withdrawn for safety or effectiveness2
Dosing in studiesPhase 2 postoperative ileus trial: 0.03 mg/kg IV twice daily3Former Geref label dosing not confirmed in an available source, so not shown
Half-lifeabout 2 hours (IV, healthy volunteers)4About 4 minutes after IV injection;5 no confirmed value under the skin
Time to peak (Tmax)GH peak about 0.67 hours after IV dosing4Not confirmed for injection under the skin
Dosing frequencyTwice daily in the ileus trial (IV)Not shown (label text not confirmed)
Typical vial sizes2, 5 or 10 mg powder2, 6 or 9 mg powder
Notable warningsNo label. Prohibited in sport (WADA)No current label. Prohibited in sport (WADA)

Reviewed . Half-life figures are shown only where the value Dose Track uses agrees with the cited source.

Why does the receptor matter?

Growth hormone is controlled by two signals: GHRH, which tells the pituitary to release it, and ghrelin, which amplifies that release through a separate receptor. Sermorelin copies GHRH. Ipamorelin copies ghrelin's effect, and in the original animal work it was described as the first selective growth hormone secretagogue.1 Because they work on different receptors, they are often discussed together.

What human evidence exists?

  • Ipamorelin: a pharmacokinetic study in healthy volunteers (IV) found a half-life of about 2 hours.4 A phase 2 trial for postoperative ileus (0.03 mg/kg IV twice daily) found no significant difference from placebo on its main outcome.3
  • Sermorelin: approved and used in children with GH deficiency for years as Geref. After IV injection its half-life was about 4 minutes.5 The product was discontinued in 2008; FDA later determined that was not for safety or effectiveness reasons.2
This page summarizes labels and published studies. It is not personalized medical advice; confirm any dose or change with your prescriber.
CJC-1295 with DAC vs without DAC: what does DAC change?Days-long vs short-acting GHRH analog BPC-157 vs TB-500: what does the evidence actually show?Mostly preclinical evidence, 2026 FDA status

Frequently asked questions

Is ipamorelin the same as sermorelin?+
No. Ipamorelin acts on the ghrelin (GHS) receptor; sermorelin is a GHRH analog that acts on the GHRH receptor. Both lead to growth hormone release.1
Is sermorelin FDA approved?+
It was, as Geref, for diagnosing and treating growth hormone deficiency in children. The product was discontinued in 2008, and FDA determined that was not for safety or effectiveness reasons.2
What is the half-life of ipamorelin?+
About 2 hours after IV dosing in healthy volunteers. There is no published human value for injection under the skin.4
Can I track ipamorelin and sermorelin in Dose Track?+
Yes. Both are built in, with reconstitution math so each amount shows in syringe units, and reminders.

Sources

  1. Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998.
  2. Determination that Geref (sermorelin acetate) was not withdrawn from sale for reasons of safety or effectiveness. Federal Register 78 FR 14095, March 4, 2013.
  3. Beck DE, et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for postoperative ileus. Int J Colorectal Dis. 2014.
  4. Gobburu JV, et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin in human volunteers. Pharm Res. 1999.
  5. Soule S, et al. Pharmacokinetics of sermorelin (GHRH 1-29) after intravenous injection. 1994.

All compound comparisons · Ipamorelin guide · Sermorelin guide · All compound guides