GHRH analog

CJC-1295 is GHRH(1-29) with four amino acid substitutions and a maleimide group that makes it latch permanently onto albumin in the bloodstream, stretching a peptide with a four-minute half-life into one lasting almost a week. In the one published human trial, single subcutaneous doses raised growth hormone 2- to 10-fold for six days or more and IGF-1 1.5- to 3-fold for 9-11 days, with an estimated half-life of 5.8-8.1 days. That is the entire human efficacy literature: 28- and 49-day dose-ranging studies in healthy volunteers, with no measurement of muscle, fat, strength or anything else clinical. Confusingly, most of what is sold as "CJC-1295" is the version without the albumin-binding group, which is simply modified GHRH(1-29) and lasts hours, not days.

Sermorelin is GHRH(1-29), the shortest fragment of growth hormone-releasing hormone that keeps full activity, and it is the parent of every GHRH analog including tesamorelin and CJC-1295. It was a licensed medicine: a diagnostic injection for pituitary function and, briefly, a treatment for short stature in children. It reliably releases growth hormone, but as a treatment it lost to recombinant growth hormone in head-to-head comparisons — children on daily growth hormone grew faster than children on GHRH(1-29), and in a randomized comparison only the growth hormone group gained height relative to bone age. Its half-life is about four minutes. It is no longer marketed in the US, and there is no trial of it in healthy adults for any purpose.

Tesamorelin (Egrifta) is a synthetic version of growth hormone-releasing hormone (GHRH). It makes the pituitary release more of the body's own growth hormone. It is approved to reduce excess abdominal fat in people with HIV. In two phase 3 trials, daily injections cut visceral (deep abdominal) fat by about 15% more than placebo over 26 weeks while leaving fat under the skin alone, and it also lowered liver fat. The fat returns once treatment stops. One trial in older adults reported better executive function, but a later trial in people with HIV found no clear cognitive benefit.