Origins and Clinical Trials

Ipamorelin's path runs from a Danish chemistry programme in the 1990s, through a decade of animal research, to hospital wards in the United States, and finally to doping laboratories.

A Screening Programme in Denmark

In the 1990s several companies were searching for small molecules that could stimulate growth hormone, partly as a possible alternative to growth hormone injections. Novo Nordisk's team in Måløv built a series of short peptides and published the most promising, coded NNC 26-0161, in the European Journal of Endocrinology in 1998. It was given the name ipamorelin.

Testing in Animals

Novo Nordisk scientists and university partners in Aarhus and Gothenburg then examined what repeated doses did in rats. They looked at bone length, bone mineral, muscle strength and protein breakdown, often in animals given steroid drugs that cause muscle and bone loss. A rat study also compared routes of delivery and found that around a fifth of a nasal dose reached the bloodstream.

The First Human Data

A dose-escalation study in healthy male volunteers, analysed with researchers at the University at Buffalo and published in 1999, described how ipamorelin is handled by the body and how strongly it releases growth hormone. Eight men were studied at each of five infusion rates.

A New Use: Gut Recovery After Surgery

Because the ghrelin receptor also speeds up movement of the gut, interest later shifted to postoperative ileus, the temporary stall of the bowel that often follows abdominal surgery. Helsinn Therapeutics (U.S.) ran a Phase 2 trial from 2008 to 2009 in 117 patients having bowel resection. A larger Phase 2 study with 320 participants ran from 2011 to 2014.

Where It Stands

The first trial, published in 2014, found no significant difference from placebo. The trial registry lists the second as completed but shows no posted results. No regulator has approved it, and ipamorelin remains an experimental compound. In the meantime it has appeared in products seized by customs and in anti-doping research.