Daily ipamorelin injections increased longitudinal bone growth rate, body weight, and GH release dose-dependently in rats over 15 days, without desensitization of the GH response.
No desensitizationIpamorelin maintained its GH-releasing effect throughout 15 days of three-daily dosing, with dose-dependent bone growth
What the researchers found
Ipamorelin (18-450 μg/day SC, three daily injections for 15 days) increased longitudinal bone growth rate and body weight dose-dependently in rats, with sustained GH release throughout the treatment period.
Why it matters
This is the first demonstration that ipamorelin can translate its selective GH-releasing activity into actual bone growth. The sustained response without desensitization is particularly important for potential therapeutic applications.
How the study worked
Animal study in rats. Ipamorelin at 0, 18, 90, and 450 μg/day was injected subcutaneously three times daily for 15 days. Longitudinal bone growth rate (proximal tibial epiphysis), body weight, and plasma GH were measured.
What this study cannot tell us
Rat study with relatively short duration. Bone growth rate in young growing rats may not predict effects in adult bone metabolism. No comparison to direct GH injection.
How to read the evidence
Preliminary animal evidence with clear dose-response in bone growth and body weight, with the advantage of sustained GH response over the treatment period.
When this study was published
Published in 1999. Ipamorelin's bone and growth effects have been further studied, contributing to its profile as a potentially therapeutic GH secretagogue.
The bigger picture
Growth hormone deficiency causes short stature in children and bone loss in adults. A selective GH secretagogue that sustainably promotes bone growth could offer an alternative to GH injections with fewer side effects.
Questions still open
- Does ipamorelin maintain bone growth effects over longer treatment periods?
- Could ipamorelin treat growth hormone deficiency-related short stature in children?
- Does the bone growth effect translate to increased bone density in adults?
Common questions
Can ipamorelin make bones grow?
Why is the lack of desensitization important?
Read the original research
Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats.
Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society, 9(2), 106-13
Citation
Johansen, P B; Nowak, J; Skjaerbaek, C; Flyvbjerg, A; Andreassen, T T; Wilken, M; Orskov, H. (1999). Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats.. Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society, 9(2), 106-13.