What Is CJC-1295? With DAC vs. No DAC Explained

CJC-1295 is one of the most widely discussed research peptides in the growth hormone space, and also one of the most frequently misunderstood. The confusion stems from the fact that there are two distinct variants -- CJC-1295 With DAC and CJC-1295 No DAC (sometimes called "Modified GRF 1-29") -- that share a name but behave differently in the body.

This guide explains both variants, how they work, what the clinical data shows, and how they compare to each other and to other GH-releasing peptides.

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What Is CJC-1295?

CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH), the natural hormone produced by the hypothalamus that signals the pituitary gland to release growth hormone (GH). The native GHRH molecule has a very short half-life -- just minutes in the bloodstream -- which limits its practical utility. CJC-1295 was engineered to solve this problem.

The base structure of CJC-1295 is a modified version of GHRH(1-29), the first 29 amino acids of natural GHRH, with four amino acid substitutions that make it resistant to enzymatic degradation. This is where the two variants diverge.

CJC-1295 With DAC adds a Drug Affinity Complex, a maleimido-propionyl group that covalently bonds to serum albumin (a blood protein) after injection. This albumin binding extends the half-life to approximately 6 to 8 days, allowing once-weekly dosing.

CJC-1295 No DAC (also known as Modified GRF 1-29 or Mod-GRF) retains the four amino acid substitutions but omits the DAC modification. Its half-life is approximately 30 minutes -- much longer than native GHRH but dramatically shorter than the DAC variant. This shorter duration produces discrete, pulsatile GH release rather than sustained elevation.

Both variants activate the same GHRH receptor on the pituitary gland. The difference is entirely in how long they remain active in the bloodstream.

View the CJC-1295 No DAC research profile or the CJC-1295 With DAC research profile on PeptidePrices.

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How Does CJC-1295 Work?

Both CJC-1295 variants work by binding to GHRH receptors on somatotroph cells in the anterior pituitary gland, triggering the release of growth hormone.

GH axis stimulation. Unlike exogenous human growth hormone (HGH) injections -- which introduce GH directly and bypass the body's regulatory system -- CJC-1295 stimulates endogenous GH production. This means the pituitary gland is doing the work, and the natural feedback loop involving IGF-1 remains intact. A 2006 study published in the Journal of Clinical Endocrinology and Metabolism (PMID: 17018654) confirmed that pulsatile GH secretion persists even during continuous CJC-1295 stimulation -- the compound does not flatten or abolish the natural GH rhythm.

Dose-dependent GH and IGF-1 elevation. The landmark human pharmacokinetic study by Teichman et al. (JCEM, 2006, PMID: 16352683) demonstrated that a single subcutaneous injection of CJC-1295 With DAC at 30-60 mcg/kg produced sustained, dose-dependent increases in GH levels (2 to 10-fold) and IGF-1 levels (1.5 to 3-fold) lasting up to 14 days. No serious adverse events were reported.

Downstream effects. Through elevated GH and IGF-1, CJC-1295 activates the same downstream pathways as growth hormone itself -- including increased lipolysis (fat breakdown), enhanced protein synthesis, improved recovery, and effects on bone mineral density and connective tissue. The difference is that these effects are achieved through physiological pituitary stimulation rather than pharmacological GH replacement.

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With DAC vs. No DAC: The Key Differences

This is the most important distinction to understand when researching CJC-1295.

Feature	CJC-1295 With DAC	CJC-1295 No DAC (Mod-GRF 1-29)
Half-life	~6-8 days	~30 minutes
Dosing frequency	Once weekly	2-3 times daily
GH release pattern	Sustained elevation	Discrete pulses
IGF-1 effect	Prolonged, steady increase	Shorter, pulsatile increase
Mimics natural GH rhythm	Less closely	More closely
Often paired with GHRPs	Less commonly	Yes (especially ipamorelin)

Why does the release pattern matter? The body naturally releases GH in discrete pulses throughout the day, with the largest pulse occurring during deep sleep. Research suggests that maintaining this pulsatile pattern is important for optimal downstream signaling. CJC-1295 No DAC, with its shorter half-life, produces GH pulses that more closely mimic this natural rhythm. The With DAC variant produces a more sustained elevation, which may be advantageous for some research applications but is further from the physiological pattern.

The ipamorelin pairing. CJC-1295 No DAC is frequently studied in combination with ipamorelin (a selective growth hormone-releasing peptide) because GHRH and GHRP work through complementary mechanisms on the pituitary. GHRH (the pathway CJC-1295 activates) increases the amplitude of GH pulses, while GHRP (the pathway ipamorelin activates) increases the frequency. Together, they produce a synergistic effect that neither achieves alone.

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Safety Profile

PeptidePrices assigns CJC-1295 No DAC a safety rating of 7 out of 10 and CJC-1295 With DAC a 6 out of 10.

No DAC (7/10). Human pharmacokinetic data exists. Generally well-tolerated in studies. Reported side effects include transient water retention, tingling, and flushing. The short-acting nature means effects dissipate quickly.

With DAC (6/10). Also studied in humans with available PK data. The slightly lower safety rating reflects one unexplained death during clinical trials (which investigators noted may have been unrelated to the compound) and the longer half-life, which means any adverse effects would persist for days rather than hours.

Neither variant is FDA-approved. Both are sold as research chemicals.

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CJC-1295 vs. Other GHRH Analogues

• Tesamorelin is an FDA-approved GHRH analogue (Egrifta) with the strongest clinical evidence base. Short half-life (~26 minutes), similar to CJC-1295 No DAC, but with full Phase 3 clinical trial data.
• Sermorelin is a GHRH(1-29) fragment that was previously FDA-approved (discontinued for commercial, not safety, reasons). Shorter-acting and generally considered less potent than CJC-1295.
• GHRP-6 is a growth hormone-releasing peptide (not a GHRH analogue). Works through the ghrelin receptor, not the GHRH receptor. Stimulates appetite significantly, unlike CJC-1295.

CJC-1295 occupies a middle ground: more potent and longer-lasting than sermorelin, available in two duration variants, and frequently paired with GHRPs for synergistic GH release.

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Dosing in Research Settings

The following is for informational purposes only and does not constitute medical advice.

CJC-1295 With DAC has been studied in humans at doses of 30-60 mcg/kg administered subcutaneously once weekly. The Teichman et al. study used single-dose protocols at these levels.

CJC-1295 No DAC is typically referenced in research contexts at doses of 100-300 mcg administered subcutaneously 2-3 times daily, often in combination with a GHRP.

These figures are drawn from published studies and commonly cited research protocols. No standardized clinical dosing guidelines exist for either variant.

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Comparing CJC-1295 Prices

Pricing for CJC-1295 varies by variant, vendor, and vial concentration. It is critical to verify whether a listing is for the With DAC or No DAC version, as they are different products at different price points.

PeptidePrices tracks both variants separately and normalizes all pricing to a per-milligram basis across 19+ vendors.

See CJC-1295 No DAC prices | See CJC-1295 With DAC prices

The AI Stack Builder can help you explore GH-axis research protocols, including CJC-1295 + ipamorelin combinations.

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Wrapping Up

CJC-1295 is a well-studied GHRH analogue available in two variants that serve different research purposes. The With DAC variant offers convenience through weekly dosing and sustained GH elevation; the No DAC variant provides a more physiological pulsatile pattern and is frequently paired with ipamorelin for synergistic effects. Both have human pharmacokinetic data supporting their mechanism, and neither is FDA-approved.

Understanding the distinction between these two variants is essential before purchasing. Compare prices carefully, confirm which variant a vendor is selling, and review the published literature for your specific research context.

Compare CJC-1295 prices across all vendors at PeptidePrices -- we track prices so you don't have to.

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For research purposes only. Not for human consumption. Not medical advice. Always consult a qualified healthcare provider before making any health or supplementation decisions.