Ipamorelin vs sermorelin at a glance
| Compared | Ipamorelin | Sermorelin |
|---|---|---|
| What it copies | Ghrelin (hunger hormone) | GHRH (growth hormone-releasing hormone) |
| Receptor | Ghrelin receptor (GHS-R1a) | GHRH receptor |
| Human research | Mid-stage trials for bowel recovery after surgery | Approved for children in 1997; small adult studies |
| Status | Never approved | Formerly FDA-approved; compounded by prescription |
| Sport | Banned (WADA) | Banned (WADA) |
How do ipamorelin and sermorelin work differently?
They press two different switches on the pituitary gland. Sermorelin copies GHRH, the brain’s main “release growth hormone” signal, while ipamorelin copies ghrelin, which triggers growth hormone through a separate receptor.
That is why clinics sometimes combine a GHRH peptide with a ghrelin-type one, hoping for a bigger release.
What does the research show for each?
Sermorelin helped children with growth hormone deficiency grow and was approved for that use until 2008. Ipamorelin was tested for slow bowel recovery after surgery and didn’t show enough benefit to continue.
Neither has good trials showing benefits for muscle, fat loss or aging in healthy adults.
How do the side effects compare?
Both can cause injection-site reactions, flushing, headache and water retention, and raising growth hormone can raise blood sugar. Ipamorelin was chosen for research because it raised cortisol and prolactin less than older ghrelin-type peptides.
Which is legal?
Sermorelin can be compounded with a prescription in the US. Ipamorelin is not approved, and the FDA lists it among compounding substances with safety concerns for outsourcing facilities.