CJC-1295 and Ipamorelin: how the two growth hormone peptides work
CJC-1295 and Ipamorelin are two synthetic peptides that are studied for their effect on the release of growth hormone (GH). They act on two different receptors in the pituitary gland, which is why researchers often study them together. This article explains how each peptide works, what the key studies found and why the combination is so common in research.
CJC-1295 and Ipamorelin
CJC-1295 and Ipamorelin are two synthetic peptides that are studied for their effect on the release of growth hormone (GH). They act on two different receptors in the pituitary gland, which is why researchers often study them together. This article explains how each peptide works, what the key studies found and why the combination is so common in research.
How growth hormone release is controlled
To understand CJC-1295 and Ipamorelin, it helps to know how the body controls growth hormone. The pituitary gland releases GH in pulses, mostly during sleep. Two main signals control these pulses:
GHRH (growth hormone releasing hormone): a hormone from the hypothalamus that stimulates GH release
Ghrelin: a hormone mainly from the stomach that also stimulates GH release, through a different receptor
A third signal, somatostatin, works as a brake and reduces GH release. CJC-1295 imitates GHRH. Ipamorelin imitates ghrelin. Because they use different receptors, their effects in research models can add up.
What CJC-1295 is
CJC-1295 is a modified version of the first 29 amino acids of GHRH. This short part of the hormone is enough to activate the GHRH receptor. Natural GHRH breaks down in the blood within minutes. CJC-1295 contains four amino acid substitutions that make it more resistant to this breakdown.
CJC-1295 with DAC and without DAC
There are two versions of CJC-1295, and the difference is important:
CJC-1295 with DAC: DAC means "Drug Affinity Complex". A chemical group allows the peptide to bind to albumin, a protein in the blood. This extends the half-life to several days.
CJC-1295 without DAC: also called modified GRF (1-29). It has the four substitutions but no albumin binding. Its half-life is about 30 minutes.
The best known human study used the DAC version. Teichman et al. (2006) published it in The Journal of Clinical Endocrinology and Metabolism. In healthy adults, a single dose of CJC-1295 with DAC increased GH levels 2 to 10 times for 6 days or more. IGF-1 levels increased 1.5 to 3 times for 9 to 11 days. The estimated half-life was 5.8 to 8.1 days. IGF-1 is a hormone that the liver produces in response to GH.
What Ipamorelin is
Ipamorelin is a pentapeptide, a peptide of five amino acids. It binds to the ghrelin receptor (also called the GH secretagogue receptor). Raun et al. (1998) described it in the European Journal of Endocrinology as "the first selective growth hormone secretagogue".
The word "selective" is the key point of that study. Older GH secretagogues, such as GHRP-6 and GHRP-2, also increased the stress hormones ACTH and cortisol in animal studies. In the experiments by Raun et al., Ipamorelin released GH without a relevant increase in ACTH or cortisol, even at high doses. Ipamorelin was later tested in clinical trials for a different purpose, the recovery of bowel function after surgery. A phase 2 trial did not show a clear benefit compared to placebo.
Why CJC-1295 and Ipamorelin are combined
The combination of CJC-1295 and Ipamorelin is based on a simple principle. CJC-1295 activates the GHRH receptor. Ipamorelin activates the ghrelin receptor. Both pathways lead to GH release, but through different signals. Earlier research with natural GHRH and ghrelin-like peptides showed that the combined stimulation can produce a larger GH pulse than either signal alone.
Most combination products use CJC-1295 without DAC. The reason is that its short half-life fits the short half-life of Ipamorelin, so both act during the same time window. Published controlled studies of this specific combination are rare. The rationale comes from the physiology of GH release, not from large trials.
Our CJC-1295 / Ipamorelin blend contains both peptides in one lyophilised vial for laboratory research.
CJC-1295 and Ipamorelin compared to other GH peptides
CJC-1295 and Ipamorelin belong to a larger group of peptides that are studied in connection with the GH axis:
Tesamorelin: a GHRH analogue that is approved in the US for a specific medical indication (abdominal fat in HIV-associated lipodystrophy). See Tesamorelin 10 mg.
IGF-1 LR3: a modified form of IGF-1 that acts downstream of GH, directly on the IGF-1 receptor. See IGF-1 LR3 1 mg.
GHRP-2 and GHRP-6: older ghrelin receptor agonists with less selectivity than Ipamorelin.
Regulatory status of CJC-1295 and Ipamorelin
Neither CJC-1295 nor Ipamorelin is an approved medicine. Both are prohibited in sport. WADA lists GHRH analogues and GH secretagogues under section S2 of its Prohibited List, and they are banned at all times.
Both peptides are supplied as lyophilised powder. Our guide on how to reconstitute peptides explains how to dissolve them and calculate the concentration.
Frequently asked questions about CJC-1295 and Ipamorelin
What is the difference between CJC-1295 with DAC and without DAC?
Is Ipamorelin a SARM?
Is CJC-1295 the same as Tesamorelin?
Sources
Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA (2006). Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. The Journal of Clinical Endocrinology and Metabolism. doi:10.1210/jc.2005-1536
Raun K, Hansen BS, Johansen NL, et al. (1998). Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. doi:10.1530/eje.0.1390552
World Anti-Doping Agency. Prohibited List. wada-ama.org
This article summarises published research for information only. It is not medical advice. All products on this site are sold for laboratory research use only and are not intended for human or veterinary use.
