Growth Hormone Releasing Peptide-2
(Pralmorelin)

1970s-1980s

The Search for Growth Hormone Release

Building Keys Without Knowing the Lock

Scientists knew the brain controlled growth hormone release, but the signals were complex. The hypothalamus released GHRH (growth hormone releasing hormone) which triggered the pituitary. But GHRH alone didn't explain everything about growth hormone secretion.

Cyril Bowers at Tulane University took a different approach. Instead of studying natural hormones, he created synthetic peptides and tested whether any could trigger growth hormone release. It was like designing keys and seeing which ones opened the door.

Remarkably, some worked. Short synthetic peptides with no resemblance to natural GHRH could trigger powerful growth hormone release. Something was binding these peptides — a receptor nobody had identified.

1989-1995

GHRP-2 Emerges

Optimizing the Signal

Bowers' team refined their peptides, creating increasingly potent versions. GHRP-6 came first, then GHRP-2 (also called GHRP-6 analog or later Pralmorelin). GHRP-2 was more potent and more selective than its predecessor.

The six-amino-acid peptide could increase growth hormone levels 7 to 15 times above baseline — a massive pulse that mimicked or exceeded the body's natural nighttime surges. It worked through a mechanism distinct from GHRH, suggesting the two could work together.

But without knowing what receptor these peptides bound to, understanding was incomplete. Bowers called it the Growth Hormone Secretagogue Receptor (GHS-R), knowing it existed but not knowing its natural ligand.

1996-2005

Finding Ghrelin

The Natural Key Reveals Itself

In 1999, Japanese researchers discovered ghrelin — a hormone released by the stomach that stimulated appetite and growth hormone release. When they characterized its receptor, it was the same one that GHRP-2 bound to. Bowers' synthetic key had led to the discovery of nature's key.

Ghrelin was dubbed 'the hunger hormone.' It rose before meals and dropped after eating. It explained the connection between nutrition and growth. And it validated decades of GHRP research.

Now scientists understood the system: ghrelin from the gut, working alongside GHRH from the hypothalamus, controlled growth hormone release. GHRP-2 was a potent ghrelin mimic that could amplify this natural system.

2005-2015

Clinical Development and Athletic Use

Promise and Controversy

GHRP-2 entered clinical development. In Japan, it was approved as Pralmorelin for diagnostic testing of growth hormone deficiency. Elsewhere, it remained a research compound, though clinical trials explored treatment of growth hormone deficiency and age-related hormone decline.

Meanwhile, athletes discovered GHRPs. The peptides offered a way to boost growth hormone without injecting the hormone itself. They were harder to detect than growth hormone doping. Anti-doping agencies scrambled to develop tests.

The performance enhancement underground drove demand. GHRP-2 became widely available from research chemical suppliers, used by bodybuilders and athletes despite lack of regulatory approval.

2015-Present

Research Continues

Aging, Muscle, and Beyond

Interest in growth hormone secretagogues persists. As populations age, the appeal of safely boosting declining growth hormone levels grows. GHRP-2's ability to stimulate natural pulsatile release — rather than flooding the body with constant hormone — may offer advantages.

Research explores applications beyond growth hormone: the ghrelin system affects appetite, metabolism, inflammation, and even mood. GHRP-2 and related peptides may have applications in muscle wasting, frailty, and metabolic disorders.

But regulatory approval in Western countries hasn't followed. GHRP-2 remains in the gray zone — a research compound with a devoted following, extensive scientific literature, but limited official therapeutic status.