CJC-1295 + Ipamorelin

What it is

The stack consists of two peptides of reputable origin. CJC-1295 was developed by the Canadian company ConjuChem as a stabilized variant of the first 29 amino acids of the body’s own GHRH, with 4 amino acid substitutions that protect the molecule from rapid breakdown. Ipamorelin comes from Novo Nordisk research and was described in 1998 as the first selective growth hormone releaser. It is a pentapeptide, that is, a chain of 5 amino acids.

The naming question is important. CJC-1295 exists with and without DAC, an anchor that binds the peptide to the blood protein albumin and keeps it in the blood for days. According to a recent review, the classic stack with ipamorelin mostly uses the short-acting form without DAC, which is also traded as Mod GRF 1-29. Both variants have their own entries on this site; this page is about the combination.

How it is supposed to work

Growth hormone is not released evenly but in pulses. Two signals control these pulses: GHRH fires the starting gun, ghrelin amplifies it via its own receptor, GHSR-1a. The whole thing is braked by somatostatin and by feedback via IGF-1. The idea of the stack: CJC-1295 occupies the GHRH door, ipamorelin the ghrelin door, and together they are supposed to produce a strong but naturally timed pulse.

This logic is not made up. In a 1990 study in 18 healthy men, GHRH and a ghrelin-like peptide together released considerably more growth hormone than either alone, and a 2009 paper in 47 men confirmed this synergy. Because the body’s own brakes remain intact, the route via the body’s own gland is considered more physiological than injected growth hormone, which bypasses the axis.

Why ipamorelin is considered the clean partner

Older ghrelin mimetics such as GHRP-2 and GHRP-6 raise cortisol and prolactin in addition to growth hormone and often cause hunger. Ipamorelin did not do this in animal studies: even at amounts more than 200 times higher than needed for half the growth hormone effect, ACTH and cortisol did not rise above the level after GHRH, and prolactin, LH, FSH and TSH remained unchanged. In humans, a phase 1 study showed a clear growth hormone pulse peaking after 40 to 60 minutes and a half-life of 2 hours, according to a review without appreciable effect on other hormones of the pituitary or adrenal gland.

It is precisely this selectivity that makes ipamorelin the most popular partner for CJC-1295: a short, targeted pulse without the hormonal bycatch of its predecessors.

Sleep, age and the somatopause

With age, growth hormone release drops markedly; this is called the somatopause. A large analysis of 149 healthy men between 16 and 83 years of age showed that the proportion of deep sleep falls from 18.9 percent in young adulthood to 3.4 percent in midlife, and growth hormone release falls in parallel. Independently of age, the amount of growth hormone was linked to deep sleep. This feeds the hope of amplifying a signal that naturally declines.

User circles consistently report deeper, more restful sleep in the first weeks, along with better recovery and, over weeks, firmer skin. Many have their IGF-1 measured and see an increase. These are user reports, not proof of efficacy: that the hormone axis responds is plausible and fits the studies; whether better sleep or more muscle follows from it has never been studied under controlled conditions.

What the studies show

Raun et al. 1998 — the first selective releaser

Developed at Novo Nordisk, tested on rat pituitary cells, in rats and in conscious pigs. Ipamorelin released growth hormone about as strongly as GHRP-6, but unlike GHRP-6 and GHRP-2 it raised neither ACTH nor cortisol, even at amounts more than 200 times higher than the half-maximally effective one. Animal data, the basis of its reputation as the clean partner.

Gobburu et al. 1999 — ipamorelin in humans

Randomized phase 1 study with 5 infusion levels and 8 healthy men each. The pharmacokinetics were dose-proportional, the half-life was 2 hours, and each dose triggered a single growth hormone pulse, which then fell back to very low levels. Hormone levels were measured, not clinical endpoints.

Beck et al. 2014 — ipamorelin after bowel surgery

Double-blind, placebo-controlled phase 2 trial, 117 patients enrolled, 114 evaluated, treatment for up to 7 days. Well tolerated, but the primary endpoint was missed: the median time to the first tolerated solid meal was 25.3 versus 32.6 hours; the difference was not significant. A second trial with 320 participants is listed in the registry as completed; no results are posted there.

Bowers et al. 1990 and Veldhuis & Bowers 2009 — the synergy

In 18 healthy men, GHRH and a ghrelin-like hexapeptide together released growth hormone synergistically. In 47 men aged between 18 and 74, the strong synergy was confirmed; it was weaker in older men and with more abdominal fat. Both papers used peptides other than ipamorelin; they support the principle, not the specific stack.

Where the data stop

There is not a single human study on the combination of CJC-1295 plus ipamorelin. A 2026 review notes that the practice rests largely on anecdotal reasoning and that controlled evidence for synergy or changes in body composition in healthy people is lacking. In addition, according to the same review, the form of CJC-1295 without DAC mostly used in the stack has not been studied in humans at all; it sits there on the lowest of four evidence levels.

For sleep, muscle building, fat loss, skin, connective tissue and bone density there are no human data, either for the combination or for ipamorelin alone. All that exists is hormone levels and one efficacy trial in a completely different field of use, which missed its goal. The review by Sigalos and Pastuszak also names long-term safety, cancer risk and mortality under growth hormone secretagogues as open questions.

Status, approval and legal

Neither CJC-1295 nor ipamorelin is approved as a medicine in Germany, the EU or the US; both are distributed as research peptides via the gray market. In sport both are banned at all times; they are on the WADA 2026 prohibited list under S2.2.4 and are named in the annex to the German Anti-Doping Act. Since September 29, 2023, the US Food and Drug Administration (FDA) has listed ipamorelin in Category 2 of its interim policy for manufacturers under section 503B (outsourcing facilities), that is, among the substances that may present significant safety risks; as reasons it names a risk of immunogenicity with injection and serious adverse events after intravenous administration. As a matter of principle, we do not give dosage information for non-approved substances.

Safety

In the short studies, the components were well tolerated. Users most often report reactions at the injection site, a brief feeling of warmth, tingling in the hands and mild water retention, typical effects of a stimulated growth hormone axis. For ipamorelin, the FDA points to serious adverse events up to and including death after intravenous administration in a study on bowel motility, and for CJC-1295 to increased heart rate and vasodilation reactions, without conclusively assessing the cause. As with anything that raises the axis, insulin sensitivity can decrease. Because IGF-1 is a growth signal, the stack is considered risky with active cancer or unexplained growths; a clinical cancer signal has not been demonstrated, but long-term data are missing. Then there is the question of quality: in a not yet peer-reviewed analysis of 6,441 samples from 14 gray market peptides, 41.6 to 71.1 percent, depending on the standard applied, failed basic quality criteria, and 15 percent contained measurable endotoxin.

Sources

• Raun et al., European Journal of Endocrinology 1998
• Gobburu et al., Pharmaceutical Research 1999
• Beck et al., International Journal of Colorectal Disease 2014
• Bowers et al., Journal of Clinical Endocrinology and Metabolism 1990
• Veldhuis & Bowers, American Journal of Physiology Endocrinology and Metabolism 2009
• Teichman et al., Journal of Clinical Endocrinology and Metabolism 2006
• Van Cauter et al., JAMA 2000
• Sigalos & Pastuszak, Sexual Medicine Reviews 2018
• Dominikowski et al., Frontiers in Endocrinology 2026
• FDA, bulk drug substances that may present significant safety risks, as of April 22, 2026