The compounds listed under this goal act on the growth-hormone axis. What the published human work measured was hormone concentrations — growth hormone and IGF-1 — not muscle. That distinction is the single most important thing on this page, and it is almost never made. Batch certificates are published at /coa.
Teichman SL et al. Prolonged stimulation of GH and IGF-I secretion by CJC-1295. J Clin Endocrinol Metab 2006;91(3):799–805. PMID 16352683; Ionescu M, Frohman LA. Pulsatile secretion of GH persists during continuous stimulation by CJC-1295. JCEM 2006. PMID 17018654; Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998. PMID 9849822; Clinical Review Report: Tesamorelin (Egrifta). PMID 30920787
A biomarker is not an outcome
Teichman et al. reported that a single subcutaneous dose of CJC-1295 raised mean plasma growth hormone two- to ten-fold for six days or more, and IGF-1 by 1.5- to three-fold for nine to eleven days, with a half-life of 5.8 to 8.1 days.
Those are real, measured, placebo-controlled findings. They establish that the compound does what a GHRH analogue is supposed to do: it raises the hormones.
They do not establish that lean mass increased, that strength changed, or that body composition shifted, because none of that was measured. No published trial of these compounds has reported muscle gain in healthy adults as an endpoint.
The inference from “IGF-1 rose” to “muscle grew” is a plausible mechanistic story. It is not a finding, and treating it as one is the standard error in this category.
Two receptors, and why they ship together
Growth hormone release has more than one input. CJC-1295 is a GHRH analogue acting on the GHRH receptor and amplifying the size of a pulse; ipamorelin is a secretagogue acting on the ghrelin receptor and triggering one. Because the inputs are independent, the research convention is to combine one of each rather than pick between them — which is why they arrive in a single pen (CJC-1295 & Ipamorelin, explained), and why the same pen also appears in the sleep category.
Ipamorelin’s own characterisation (Raun 1998) is preclinical. Its reported advantage is selectivity: it releases GH with less effect on other pituitary hormones than the earlier GHRP compounds. There is no published human dose-ranging trial for it.
No published human trial has administered the combination and measured the result. The pairing rationale is mechanistic, not evidenced.
Tesamorelin is the exception, and its exception is narrow
Tesamorelin has the most conventional clinical history in this group (see the tesamorelin overview) — but its trials studied HIV-associated lipodystrophy, and what they measured was visceral fat reduction. A later meta-analysis in that population also reported improvements in lean body mass and IGF-1.
That is a lean-mass finding, and it is worth stating accurately: it comes from patients with a specific metabolic condition, under supervision, over 26 to 52 weeks. It does not transfer to a healthy adult training in a gym, and no trial has tested that.
What is not known
There is no long-term human safety data for CJC-1295 or ipamorelin. Neither holds a marketing authorisation, so neither is covered by post-marketing surveillance — which means the absence of reported adverse effects reflects the absence of a reporting system as much as anything about the compounds — and the same applies under recovery, where the same compounds reappear.
All are prohibited at all times under WADA. If you compete under anti-doping rules, this entire goal category is closed to you regardless of anything else on this page.
Where to read further
The mechanism split is set out at growth hormone peptides and the specific pairing at CJC-1295 vs Ipamorelin. Dosing as it appears in the literature — including the fact that the published figures are per kilogram of bodyweight and on weekly schedules — is at CJC-1295 and Ipamorelin dosing.
What we can evidence is what is in the pen: identity, content, purity and sterility, tested per batch with the certificate reachable from its QR code. Not an outcome.
