CJC-1295 and Ipamorelin: why they are studied together

The growth-hormone axis in one paragraph

Growth hormone is released by somatotroph cells in the anterior pituitary under the control of two hypothalamic signals pulling in opposite directions. Growth-hormone-releasing hormone (GHRH) binds the GHRH receptor on the somatotroph and drives synthesis and release; somatostatin binds its own receptors and holds release back. A third input, ghrelin, acts at the growth-hormone secretagogue receptor (GHS-R1a) on both the pituitary and the hypothalamus, where it is thought to amplify the GHRH signal and to reduce somatostatin tone at the same time.

The output of that arrangement is pulsatile, not steady. In every species studied, GH is secreted in discrete pulses with troughs close to zero between them, the largest pulses in rodents and humans arriving during slow-wave sleep. Animal models show the pattern itself carries information: pulsatile and continuous exposure to the same total amount of GH produce different downstream responses in IGF-1 and in hepatic gene expression. That is why the pharmacology of a GH-axis compound is described in terms of pulse amplitude and timing rather than simply more or less hormone, and why the half-life of a research compound in this family is a design variable rather than a footnote.

CJC-1295: a stabilised GRF(1-29) analog, with or without DAC

Native GHRH is 44 residues long; the first 29, GRF(1-29), are the shortest fragment with full activity at the receptor, and that fragment is sermorelin. Dipeptidyl peptidase-IV clips it within minutes. CJC-1295 is GRF(1-29) with four substitutions that close that gap: D-alanine at position 2, glutamine at 8, alanine at 15 and leucine at 27. The first blocks the DPP-IV cleavage site; the other three replace residues prone to oxidation and deamidation. It also appears in the literature as modified GRF(1-29).

The name originally belonged to a version carrying a Drug Affinity Complex: a maleimidopropionic acid linker on a C-terminal lysine that covalently binds circulating albumin. In early human pharmacokinetic work that linker extended the half-life from minutes to several days and produced a sustained rise in GH and IGF-1 rather than a pulse. CJC-1295 No DAC keeps the four substitutions without the linker and clears on the order of half an hour, the form used when a study wants a single, measurable pulse.

We stock No DAC only, at /products/cjc-1295/, with the form named on the label and certificate. Whoever you order from, check which form the document describes; the two are different molecules with different molecular weights.

Ipamorelin: a selective pentapeptide secretagogue

Ipamorelin is a five-residue peptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) developed in the 1990s from the growth-hormone-releasing-peptide series that began with GHRP-6. It does not act at the GHRH receptor; it is an agonist at GHS-R1a, the ghrelin receptor, which was identified after the synthetic peptides that activate it.

The original characterisation work, in cultured rat pituitary cells and in vivo in rats and swine, reported GH release comparable to GHRP-6 with one distinguishing feature: at the concentrations that released GH in those models, ipamorelin produced no measurable rise in ACTH, cortisol or prolactin, where GHRP-6 and GHRP-2 raised them in the same systems. It was also reported not to affect FSH, LH or TSH. That selectivity is why ipamorelin is discussed as a separate class member rather than as another GHRP.

The limits of that finding are worth stating. It comes from specific animal and cell models and a small amount of early-phase human pharmacology in the late 1990s. Ipamorelin was taken into clinical development for one unrelated indication, postoperative ileus, and that program was discontinued, so the human literature is thin relative to GHRP-6. Selectivity reported in a rat is a property of that model until it is tested elsewhere.

Why the pairing appears in the literature

The two compounds act at two receptors on the same somatotroph: the GHRH receptor mainly through cyclic AMP, GHS-R1a mainly through phospholipase C and intracellular calcium. A secretagogue also acts upstream at the hypothalamus, where it is thought to stimulate GHRH neurons and reduce somatostatin tone. In the literature's framing, a GHRH analog sets the amplitude of the pulse a somatotroph can produce, and a secretagogue is the trigger that releases it while lifting the brake.

The synergy claim rests on three kinds of study. Human pharmacology work from the late 1980s and 1990s co-administered GHRH with GHRP-6, GHRP-2 or hexarelin and reported GH release greater than the sum of either alone. Rat and cell-culture work reproduced the greater-than-additive response at the receptor level. Later pharmacokinetic modelling described the two inputs as multiplicative. Two caveats: most of that human work used GHRP-6 or GHRP-2, not ipamorelin, so the extension to ipamorelin is inferred from mechanism plus thinner preclinical data; and a larger GH pulse is a pharmacological readout, not a health outcome.

The No DAC form is used because both compounds then act over the same window of minutes: produce a pulse, measure it, watch the system return to baseline.

Where sermorelin and tesamorelin fit

Sermorelin is unmodified GRF(1-29), the parent fragment CJC-1295 No DAC is a stabilised version of: same receptor, same fragment, shorter action because DPP-IV cleaves it. It was for a period an approved diagnostic product before being withdrawn for commercial rather than safety reasons, so it has the most complete human pharmacology record of any compound on this page. The library entry is at /library/sermorelin/.

Tesamorelin is the full 44-residue GHRH sequence with a trans-3-hexenoic acid group on the N-terminus, which protects the DPP-IV site without changing the residues. It is the one compound in this family that went through full clinical development to market as a prescription drug, for one indication under one authorisation. The research reagent at /products/tesamorelin/ is a research-use reference standard, not that product; an approved drug in one indication says nothing about any other material, use or compound.

In order of how long they act at the GHRH receptor: sermorelin (minutes), CJC-1295 No DAC (up to about an hour), tesamorelin (longer), CJC-1295 DAC (albumin-bound, days). A pairing with a secretagogue is normally built on the short end of that list.

Storage, stability and reconstitution basics

Both ship as lyophilised powder, which wants three things: cold, dark and dry. Frozen for the long term, refrigerated for weeks, out of light throughout, and brought to room temperature before the seal is broken so condensation does not land on the powder. CJC-1295's position-27 leucine already replaces an oxidation-prone methionine, and ipamorelin's D-amino acids and amidated C-terminus make it a comparatively robust small peptide. Neither is fragile as a solid; both are fragile as a solution.

For reconstitution we sell bacteriostatic water at /products/bac-water/. The general practice is to run the diluent down the inside wall of the vial rather than onto the powder, then swirl until clear without shaking, since foaming and shear denature peptides. In solution the material is on a clock: refrigerated, protected from light, with a working life measured in weeks at best. The benzyl alcohol suppresses microbial growth; it does nothing to slow peptide degradation. Reconstituting the two vials separately keeps their stability clocks, and their certificates, separate.

This page carries no dose, frequency, route or cycle for either compound. The reported protocol for the pairing is at /protocols/stacks/growth-hormone-rejuvenation/, with the research-use-only and consult-a-physician lines it needs to carry; those apply here as well.

Reading the certificate for each lot

Pure North commissioned Canada Peptide Testing, as a paying client. Published reports for this product: 10 mg vial, CPT-CJCN-10-091226 (99.12% area purity; 10.34 mg measured content). Read the original documents at /lab-results/.

The published Canada Peptide Testing reports measure RP-HPLC-UV area purity and content. They do not include mass-spectrometry identity, endotoxin, water content or a related-substances breakdown. These results do not establish clinical safety or regulatory approval.

Match the compound, vial size and printed lot to the report before relying on it. An assigned reference is not automatically the batch code on a vial. If they differ, email purenorthpeptides@proton.me with the vial details and report number to confirm the connection. Do not extend a report to another size or lot.

Pure North commissioned Canada Peptide Testing, as a paying client. Published reports for this product: 10 mg vial, CPT-IPA-10-091226 (99.98% area purity; 10.82 mg measured content). Read the original documents at /lab-results/.

The published Canada Peptide Testing reports measure RP-HPLC-UV area purity and content. They do not include mass-spectrometry identity, endotoxin, water content or a related-substances breakdown. These results do not establish clinical safety or regulatory approval.

Match the compound, vial size and printed lot to the report before relying on it. An assigned reference is not automatically the batch code on a vial. If they differ, email purenorthpeptides@proton.me with the vial details and report number to confirm the connection. Do not extend a report to another size or lot.

Regulatory status in Canada

Neither CJC-1295 nor ipamorelin is authorised by Health Canada for human use. Neither carries a DIN (an approved drug) or an NPN (a licensed natural health product), and neither is sold here for that purpose. Both are supplied as research-use-only laboratory reference standards, a statement about intended use that constrains the seller as much as the buyer: no therapeutic claims, no outcome claims, research framing throughout. This section is general information, not legal advice.

Two things beyond that. Both compounds sit on the World Anti-Doping Agency Prohibited List under peptide hormones and growth factors, in and out of competition, which matters to anyone whose work touches tested sport. And tesamorelin's drug authorisation in one indication is sometimes read as a signal about the whole family; it is not. Authorisation attaches to a specific product, sponsor and indication, not to a molecule class.

Orders ship within Canada only, so there are no customs steps. Classification is compound-specific and regulation changes; Health Canada is the authority on any particular compound, and your own position is a question for a qualified professional rather than a supplier's website, including this one.

Frequently asked

What is the difference between CJC-1295 DAC and No DAC?

Both are GRF(1-29) with the same four stabilising substitutions. The DAC version adds a Drug Affinity Complex, a linker that binds serum albumin and extends the plasma half-life from minutes to days, producing a sustained GH elevation in the early pharmacokinetic work. The No DAC version has no linker, clears in under an hour, and produces a single pulse. We stock No DAC only. They are different molecules with different molecular weights, so check which one a certificate names.

Why are CJC-1295 and ipamorelin used together in research?

They act at two different receptors on the same pituitary cell: CJC-1295 at the GHRH receptor, ipamorelin at the ghrelin receptor GHS-R1a. Human pharmacology work with GHRH plus older secretagogues (GHRP-6, GHRP-2, hexarelin) reported greater-than-additive GH release, and rat and cell-culture work reproduced it. The extension to ipamorelin specifically is inferred from receptor mechanism plus a smaller body of preclinical data, not from a large direct literature.

Is ipamorelin the same as GHRP-6 or hexarelin?

No. All three are synthetic agonists at GHS-R1a, but GHRP-6 and hexarelin are hexapeptides and, in the rat and swine models where they were compared, raised cortisol and prolactin alongside GH; GHRP-6 also acts on appetite signalling. Ipamorelin is a pentapeptide reported in the same models to release GH without a measurable ACTH, cortisol or prolactin response. That selectivity is a finding from specific models, not a general property.

How should CJC-1295 and ipamorelin be stored?

As lyophilised powder: frozen for long-term storage, refrigerated for weeks, protected from light, and brought to room temperature before the seal is broken. Once reconstituted, refrigerated, out of light, and used within a limited working life; bacteriostatic water controls microbial growth but does not stop peptide degradation. Reconstitute the two vials separately. This page carries no dose, frequency, route or cycle; the reported protocol is at /protocols/stacks/growth-hormone-rejuvenation/.

Are CJC-1295 and ipamorelin legal in Canada?

They are supplied as research-use-only laboratory reference standards, a category distinct from products approved for human use. Neither has a Health Canada authorisation (no DIN, no NPN), both are on the WADA Prohibited List, and classification is compound-specific. This is general information rather than legal advice; verify your own situation with Health Canada or a qualified professional.

Referenced in our catalog

Related library entries