Ipamorelin and sermorelin are both studied for raising the body's own growth hormone release, which is why they are frequently compared. Sermorelin is an analog of growth hormone-releasing hormone (GHRH) made of its first 29 amino acids. Ipamorelin is a growth hormone secretagogue that acts on the ghrelin receptor. Neither is currently sold as an FDA-approved product, but sermorelin was once approved under the brand name Geref.
At a glance
| Ipamorelin | Sermorelin | |
|---|---|---|
| What it is | Selective growth hormone secretagogue studied for stimulating GH release without raising cortisol or prolactin | GHRH analog made of GHRH's first 29 amino acids; long used to support natural GH production |
| How it's thought to work | Acts on the ghrelin receptor to stimulate GH release without significantly affecting cortisol, prolactin, or ACTH | Binds pituitary GHRH receptors to stimulate the body's own pulsatile growth hormone release |
| Regulatory status | Not FDA-approved; a research compound | Originally FDA-approved as Geref, since discontinued; compounded versions today are not FDA-approved |
| Strength of evidence | Clinical studies show selective GH release; formal human trial data beyond that is limited | Historically FDA-approved and used diagnostically; extensive clinical familiarity from that approved history |
| Reported side effects | Increased hunger, water retention, tingling or numbness in extremities, headache; joint pain rare | Injection site reactions, flushing, headache, mild water retention; generally milder than direct GH |
| Common vial sizes | 2mg, 5mg | 2mg, 5mg |
| Mixing math example | 5 mg + 2 mL BAC water = 2,500 mcg/mL, 25 mcg per unit | 5 mg + 2 mL BAC water = 2,500 mcg/mL, 25 mcg per unit |
Key differences
Sermorelin binds GHRH receptors in the pituitary gland to stimulate the body's own pulsatile growth hormone release. Ipamorelin acts on the ghrelin receptor instead, and research describes it as releasing growth hormone without significantly affecting cortisol, prolactin or ACTH.
Sermorelin's branded product, Geref, was FDA-approved and used diagnostically to test for growth hormone deficiency before it was discontinued; compounded versions sold today are not FDA-approved. Ipamorelin has never been an approved product.
Sermorelin's reported side effects include injection site reactions, flushing, headache and mild water retention. Ipamorelin's include increased hunger, water retention, tingling or numbness in the extremities and headache.
What the research covers
Sermorelin has extensive clinical familiarity from its approved history as Geref. Ipamorelin's human research consists of studies showing selective growth hormone release and its pharmacokinetics, without an approved product behind it.
Sources
- Ipamorelin, the first selective growth hormone secretagogue. Raun K et al. European Journal of Endocrinology, 1998. Preclinical
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Gobburu JV et al. Pharmaceutical Research, 1999. Human trial
- Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. Prakash A et al. BioDrugs, 1999. Review
- Determination That GEREF (Sermorelin Acetate) Injection ... Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness. Federal Register / U.S. Food and Drug Administration, 2013. Regulatory document
Frequently asked questions
What is the difference between ipamorelin and sermorelin?
Sermorelin is a GHRH analog that acts on the GHRH receptor. Ipamorelin is a growth hormone secretagogue that acts on the ghrelin receptor. Both are studied for raising the body's own growth hormone release.
Is sermorelin FDA-approved?
Sermorelin was FDA-approved as Geref, which has since been discontinued. Compounded sermorelin sold today is not an FDA-approved product. Ipamorelin has never been FDA-approved.
Do ipamorelin and sermorelin work the same way?
No. They act on different pituitary receptors, the ghrelin receptor for ipamorelin and the GHRH receptor for sermorelin, though both lead to growth hormone release.
Are ipamorelin and sermorelin the same thing?
No. They are distinct peptides from different classes: ipamorelin is a ghrelin-receptor secretagogue and sermorelin is a fragment-based GHRH analog.
Both entries, plus the calculator
The PeptidesAI app covers Ipamorelin, Sermorelin and 68 other compounds, with a reconstitution calculator, a dose log and reminders. Free to download on iPhone.
Download on the App Store