The mechanism split above explains why these compounds are paired. It does not tell you how much human evidence sits behind each one, and that varies more than the shared class name suggests. What follows goes one level down: what happens at the receptor, what the four evidence bases actually contain, and what the regulatory record says.
At the receptor
The two receptors are separate proteins on the same pituitary cells, and the papers behind each compound show what that separation means. A GHRH analogue occupies the GHRH receptor and stimulates both synthesis and release of the body’s own growth hormone; that is how Dhillon S. Spotlight on tesamorelin in HIV-associated lipodystrophy. BioDrugs 2011. PMID 22050344 describes tesamorelin, and CJC-1295 acts on the same receptor. A secretagogue occupies the ghrelin receptor instead. Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998. PMID 9849822 showed with receptor antagonists that ipamorelin releases growth hormone through the GHRP-type receptor, not the GHRH receptor, and that, unlike the earlier GHRP-6 and GHRP-2, it did so without raising ACTH or cortisol in swine, even at doses more than two hundred times its effective dose.
One human study adds a detail worth having. Ionescu M, Frohman LA. Pulsatile secretion of GH persists during continuous stimulation by CJC-1295. J Clin Endocrinol Metab 2006. PMID 17018654 sampled blood every twenty minutes overnight in healthy men a week after a single injection. The frequency and size of the natural pulses were unchanged. What rose was the trough between pulses, about 7.5-fold, which lifted mean growth hormone by 46 percent and IGF-I by 45 percent. So a GHRH analogue does not simply make bigger pulses; it raises the floor beneath them.
Four rows, four kinds of evidence
| Compound | Receptor | Best human evidence | Endpoint measured |
|---|
| Tesamorelin | GHRH | Two 26-week randomised trials, 816 patients, HIV lipodystrophy | Visceral fat on imaging |
| CJC-1295 | GHRH | Two short placebo-controlled trials, healthy adults | Growth hormone and IGF-I in blood |
| Ipamorelin | Ghrelin (GHS-R) | One phase 2 trial, intravenous, postoperative ileus | Time to a first tolerated meal |
| CJC-1295 & ipamorelin | Both | None as a pair | None |
The first row is a clinical outcome in patients. The second is a hormone biomarker in volunteers: Teichman SL et al. Prolonged stimulation of GH and IGF-I secretion by CJC-1295. J Clin Endocrinol Metab 2006. PMID 16352683 measured growth hormone and IGF-I, not lean mass, strength or fat. The third row is not about growth hormone at all: Beck DE et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis 2014. PMID 25331030 gave intravenous ipamorelin or placebo to 114 adults after bowel surgery, found it well tolerated, and found no significant difference in time to a first tolerated meal. No published trial has given ipamorelin subcutaneously to healthy adults.
What “evidence depth” means
Depth measures documented human exposure for a stated purpose. It is not a verdict on whether a compound works for the goal you are reading about. Tesamorelin sits at the top because roughly eight hundred patients were followed for 26 weeks, with extensions to 52, under monitoring with adverse events counted, which makes its safety record more informative than an absence of reports elsewhere. CJC-1295 sits below it because its trials were short and measured hormones, and because nothing followed them. Ipamorelin sits lower still because its growth-hormone characterisation is in rat pituitary cells, rats and swine, and its one human trial answers a different question. The combined pen inherits both halves and adds nothing of its own. How that plays out for muscle is at Tesamorelin vs CJC-1295, and the reported adverse events for the pair are at CJC-1295 and ipamorelin side effects.
Tesamorelin and the Egrifta file
Tesamorelin is the one compound here with an approved indication, and its EU record deserves to be set out exactly. Ferrer Internacional submitted a centralised application for Egrifta 2 mg to the European Medicines Agency on 31 May 2011, for the reduction of excess visceral fat in treatment-experienced HIV patients (European Medicines Agency. Ferrer Internacional S.A. withdraws its marketing authorisation application for Egrifta. Press release, 26 June 2012). On 21 June 2012 the company withdrew the application while it was still under CHMP review (European Medicines Agency. Egrifta: withdrawal of the marketing authorisation application. 2012). Egrifta was therefore never authorised in the EU; there was no authorisation to lose.
The same summary records the committee’s provisional view that the product could not have been approved: lipodystrophy fat was hard to distinguish from ordinary obesity in practice, the fat reduction had not been shown to translate into a health benefit, the trial population was heavier than typical European HIV patients, and the IGF-I rise seen in a considerable number of patients was treated as a major safety concern with no long-term data to offset it. That does not change what the trials found in their own population, set out at what is tesamorelin?. It does mean that the biomarker the committee singled out as its main safety concern, a rise in IGF-I, is the same one the CJC-1295 trials reported as their result.
The anti-doping classification
The class page says all of these are prohibited at all times; the list itself is more specific. Section S2.2.4 of the 2026 Prohibited List, in force from 1 January 2026, covers growth hormone releasing factors and lists the two mechanisms as separate lines: GHRH and its analogues, naming CJC-1293, CJC-1295, sermorelin and tesamorelin, and growth hormone secretagogues and their mimetics, naming ipamorelin (World Anti-Doping Agency. The 2026 Prohibited List, S2.2.4). If you compete under anti-doping rules, every pen on this page is closed to you.
Where the combination evidence stops, and what we can state
The Ionescu data above complicates the amplify-and-trigger picture: the “amplify” half is at least partly a raised floor rather than bigger pulses. No published trial has given the pair together, so none has tested whether adding a secretagogue changes that, and none has compared tesamorelin with CJC-1295 head to head. Sermorelin, the short-acting GHRH analogue we do not stock, is the nearest relative on mechanism, and that comparison is at CJC-1295 vs Sermorelin.
We stock two pens in this class: TESAMORELIN 32 and one combined CJC-1295 & IPAMORELIN pen, each pre-loaded in 3 ml. There is no standalone CJC-1295 or ipamorelin pen; the pairing logic is at what is CJC-1295 & Ipamorelin? and CJC-1295 vs Ipamorelin, and the combined pen is also the growth-hormone half of the Prime Performance set. An independent laboratory tests each batch for identity, purity and sterility; the certificate for your lot shows the HPLC purity figure and the concentration of the cartridge, and it opens from the QR code on the pen or from the index at /coa.
