Preclinical Research
Ipamorelin’s selectivity was measured in rats and swine
The 1998 pharmacology paper reports growth-hormone release without the ACTH and cortisol rise seen with older peptides. It is labeled preclinical because that is the evidence.
This note stays preclinical. Raun and colleagues studied ipamorelin, a pentapeptide growth-hormone secretagogue, in primary rat pituitary cells, in anaesthetised rats, and in conscious swine. Growth hormone rose. In the swine experiments the authors report that ACTH and cortisol did not rise across a wide dose range above the dose that released growth hormone.
Selectivity is a comparative claim
The comparison inside the paper is with less selective peptides such as GHRP-6, and with growth-hormone-releasing hormone. Selectivity here means “less of this other hormone in these animals,” not “safe for long-term human use.” The paper does not contain a clinical endpoint such as strength, fat mass, or recovery.
Where a human dose would have to come from
It would have to come from a human study with a stated dose, schedule, and stopping rule. This paper does not supply one. Treating a nanogram-per-millilitre growth-hormone peak in swine as a personal regimen is a category error. The DOI is 10.1530/eje.0.1390552.