CJC-1295 With DAC vs Without DAC: One Backbone, Two Drugs

The name problem first

When ConjuChem published its work in 2005, "CJC-1295" meant one specific molecule: the first 29 amino acids of growth hormone-releasing hormone with four amino acid substitutions, plus an extra lysine on the end carrying a maleimidopropionamide linker. That linker is the Drug Affinity Complex, or DAC. It exists to bond with albumin.

Research suppliers later began selling the same 29 amino acid backbone without the linker, and needed a name for it. "CJC-1295 no DAC" stuck, even though the original literature had already called that backbone Modified GRF (1-29), or Mod GRF 1-29. The result is two products sharing a brand-like name, one of which has human trial data and one of which does not.

This page is about what the linker changes and what it does not. For each product on its own, see CJC-1295 with DAC and CJC-1295 no DAC.

What the two share

Everything except the linker. Both start from GRF (1-29), the active fragment of GHRH also sold as sermorelin, and both carry the same four substitutions: D-alanine at position 2, glutamine at 8, alanine at 15 and leucine at 27. The substitutions protect the peptide from the enzymes, including DPP-IV, that break the unmodified fragment down within minutes.

Both bind the GHRH receptor on pituitary somatotrophs, and both work through the pituitary rather than around it. Somatostatin, the body's brake on GH release, still applies to either version. What differs is how long the receptor stays stimulated.

What the linker changes

In rats, the 2005 ConjuChem paper found the albumin conjugate appeared in blood within 15 minutes of injection, produced about four times the GH area under the curve of plain GRF (1-29) over two hours, and was still detectable beyond 72 hours. That paper was built to select the DAC compound; it did not characterise the bare backbone as a product in its own right.

The human data belongs to the DAC version

Teichman and colleagues (2006) ran two randomised, placebo-controlled, ascending-dose trials in healthy adults aged 21 to 61. After a single subcutaneous injection, mean GH rose 2- to 10-fold depending on dose and stayed up for six days or more; mean IGF-1 rose 1.5- to 3-fold for 9 to 11 days. With repeated dosing, IGF-1 stayed above baseline for up to 28 days. The estimated half-life was 5.8 to 8.1 days. No serious adverse reactions were reported, and the drug was best tolerated at 30 or 60 mcg/kg.

Ionescu and Frohman (2006) asked the question that matters for a long-acting GHRH: does continuous stimulation flatten the natural rhythm? Healthy men aged 20 to 40 had blood sampled every 20 minutes overnight before and a week after one injection. Pulse frequency and size did not change. The baseline between pulses rose 7.5-fold, mean GH rose 46% and IGF-1 rose 45%. The authors concluded that the raised trough, not bigger pulses, drives the IGF-1 increase.

That same year ConjuChem stopped its phase 2 trial in HIV-associated abdominal fat, which had enrolled 192 people, after a participant died. Contemporary coverage said the cause and any link to the drug were under investigation and reported no finding of causality. The indication was later won by tesamorelin, a different GHRH analogue.

What the no-DAC version is missing

There is no published human study of Modified GRF (1-29) on its own. The pharmacokinetic figures, GH curves and IGF-1 results quoted for "CJC-1295" online are from the DAC trials and describe a molecule that stays in the blood for a week. They do not transfer to a peptide that clears in hours.

The closest evidence for what a short-acting GHRH analogue does in people comes from sermorelin's small ageing studies and from tesamorelin's phase 3 programme, both covered on ipamorelin vs sermorelin and tesamorelin vs sermorelin. Reasoning from those to Mod GRF 1-29 is plausible but is inference, not data.

The no-DAC version is more common locally partly because it is the half of the CJC-1295 + ipamorelin pairing. The pairing rests on a 1990 study in which a GH-releasing peptide combined with natural GHRH released GH synergistically in 18 men; it did not use either CJC-1295 version.

The trade-off people are choosing between

The DAC version gives one injection a week-long effect and measurable, sustained IGF-1. The cost is that a raised IGF-1 for days at a time is a bigger departure from normal physiology than a nightly pulse, and an injection cannot be reversed if it does not suit.

The no-DAC version keeps the signal short, which is closer to how GHRH behaves naturally. The cost is that no one has published what it does in people, so every claim about it is borrowed.

Either way, the US FDA lists CJC-1295 among bulk substances raising compounding safety concerns, citing possible immunogenicity, difficulty characterising impurities, and serious adverse events including increased heart rate and a systemic vasodilatory reaction. The listing does not separate the two forms. The side effects hub has the wider GH-axis picture.

Status in the Philippines

Neither form is registered with FDA Philippines, and CJC-1295 has never been approved as a medicine in any country. It is not a controlled substance under RA 9165. Both circulate through research-chemical suppliers; the no-DAC form is easier to find, often pre-mixed with ipamorelin. IGF-1, the marker both trials tracked, is available at Philippine laboratories; see bloodwork in the Philippines.

Storage

Both are freeze-dried peptides that keep best refrigerated before mixing and at 2 to 8°C afterward, not frozen. Heat is the practical risk here: a vial in a parked car or a long brownout without a cooler degrades either version. The CJC-1295 calculator handles reconstitution arithmetic.