Direct Answer
Ipamorelin is a synthetic pentapeptide growth-hormone secretagogue (a ghrelin-receptor agonist) studied in preclinical models and early human pharmacology research. It is not an approved therapeutic. As of June 2026 it sits in a regulatory gray zone: ipamorelin was removed from the FDA 503A Category 2 bulk-substances list in April 2026 but not added to Category 1, and it remains not FDA-approved.
Summary Table
Evidence Level
High
Key Information
Classification
Key Takeaways
- Ipamorelin is a selective growth-hormone secretagogue (ghrelin-receptor agonist)
- Evidence is from animal studies and early human pharmacology
- It is not an approved therapeutic
Scientific Overview
In Plain English
Ipamorelin is a lab-made peptide that prompts the pituitary gland to release growth hormone. It was studied decades ago in animals and small human pharmacology studies but was not developed into an approved medicine.
Scientific Details
Ipamorelin is described as a selective growth-hormone secretagogue acting at the ghrelin (growth-hormone-secretagogue) receptor. Animal studies associate it with growth-hormone release and longitudinal bone growth, and early human pharmacokinetic-pharmacodynamic studies characterized its growth-hormone response. It is not an approved drug and lacks large human outcome studies.
How It Works
Ipamorelin is described in research as a ghrelin-receptor agonist; studies associate receptor activity with pulsatile growth-hormone release, with relatively limited effect on other hormones such as cortisol and prolactin.
Mechanism of Action
GH secretagogue activity
animal
Studies associate ipamorelin with selective growth-hormone release via the ghrelin receptor.
Evidence Level
Human Evidence
Early human pharmacokinetic-pharmacodynamic studies characterized growth-hormone responses in volunteers.
Animal Evidence
Animal studies report growth-hormone release and longitudinal bone growth.
Limitations
Evidence is largely from early-phase pharmacology conducted decades ago; ipamorelin is not an approved therapeutic and large human outcome studies are lacking.
References
- Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology.Mechanisticdoi:10.1530/eje.0.1390552 →
- Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Growth Hormone & IGF Research.Animal Studydoi:10.1054/ghir.1999.9998 →
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharmaceutical Research.Human Studydoi:10.1023/a:1018955126402 →
Alternative Names
- NNC 26-0161
Claim Boundaries
ION BLUE is an educational research aggregator. This content summarizes published scientific literature. It is not medically reviewed, is not medical advice, and is not a recommendation to use any substance. Several peptides discussed are research chemicals not approved for human use. Consult a licensed healthcare provider. This entry does not assert that ipamorelin is safe or beneficial for any use and is not a recommendation to use it.
This page summarizes published research and is for informational purposes only; it is not medical advice.