Ipamorelin: the script changed at the hospital
A molecule celebrated for releasing growth hormone ended up being tested on the return to eating after bowel surgery. That turn tells a more interesting story than its reputation does.
A hospital meal in a hormone story
Muscle seemed the obvious place to begin with Ipamorelin. Instead, the published patient trial led to a covered meal on a hospital tray. Could people recovering from bowel surgery tolerate food sooner? It is an ordinary, useful question, and, to me, it deserves far more attention than it gets.
The 2014 trial in 114 adults missed its primary endpoint, the outcome chosen in advance as the main test of success. The median time to the first tolerated meal was 25.3 h with ipamorelin and 32.6 h with placebo, with p=0.15. The lower number looks encouraging in isolation. The trial did not establish a treatment benefit.
That result belongs near the beginning of any account of ipamorelin. So does the reason anyone thought this small peptide was worth testing.
The early hormone experiments
Ipamorelin is a synthetic chain of five amino acids, the small building blocks that make up peptides. It acts at the ghrelin receptor, borrowing a signal from a hormone associated with hunger. The pituitary gland responds by releasing growth hormone.
In the original cell, rat and swine experiments, growth hormone rose while the cortisol and prolactin response stayed comparatively quiet. Older growth-hormone-releasing peptides had affected those other hormones. That selectivity was a real piece of pharmacological craft.
The restraint of that original question appeals to me: which hormones change? Much of the later excitement asks the finding to carry sleep, strength, recovery and longevity along with it. The human work supports a brief growth hormone pulse; the larger health claims still need their own outcomes.
Appetite complicates the reputation
The weight story refuses to march in one direction. Ipamorelin increased fat and leptin in mice, including mice deficient in growth hormone. In a different setting, ferrets receiving cisplatin lost less body weight after ipamorelin, while vomiting continued. Those are animal findings about very different problems.
I prefer the inconvenient animal findings to a neat fat-loss slogan. The molecule can be interesting without acquiring an imaginary successful human weight-loss trial.
Community accounts add better sleep, vivid dreams, less soreness, hunger and puffiness to the story. They are anecdotal accounts, not clinical evidence; nobody controlled the other compounds, food, exercise or expectations involved. The sports-medicine review describes an investigational compound with uncertain safety and product-quality concerns.
Choose a question
The research and clinical trials page follows the experimental story, including the numbers from the hospital study. Side effects and safety brings the animal cautions and community accounts together.
For a more specific question, there are pages on water retention, half-life and the dosage figures used in studies. The questions page deals with sleep, appetite and the CJC-1295 pairing.
I am waiting for this story to earn a better next chapter. A measured improvement in people's daily lives, followed long enough to count harms, would give it one.