CJC-1295 and Ipamorelin: What DAC Actually Changes

“CJC-1295 and Ipamorelin” is the most commonly written peptide pairing there is, and the most commonly written ambiguously. The problem is not the pairing. It is that “CJC-1295” names two compounds that clear on completely different timescales — one persists for days, the other is short-acting — and instructions that omit the suffix do not contain enough information to follow.

Three compounds, two jobs

The three belong to two different peptide classes, which is part of why they are so often confused. Growth hormone release is governed by two opposing signals, and the two classes act on different ones:

• A GHRH analogue — CJC-1295, in either form — mimics growth-hormone-releasing hormone, raising the size of a release pulse.
• A GHRP / secretagogue — Ipamorelin — acts at the ghrelin receptor, a separate pathway.

Because they act through different receptors, the two classes are pharmacologically distinct rather than two versions of one thing. Ipamorelin is specifically noted in the literature for being selective — comparatively little effect on cortisol and prolactin relative to older GHRPs.

DAC is the whole story

DAC stands for Drug Affinity Complex: a modification that binds the peptide to serum albumin so it persists for days rather than clearing rapidly. That single change produces two compounds that share a name and share almost nothing else.

Read the half-life row: one form is measured in days, the other has no characterised human half-life at all. They are different molecules, not two strengths of one, and nothing learned about one transfers to the other.

The naming is worse than the pharmacology

Strictly, the compound sold as “CJC-1295 without DAC” is modified GRF(1-29) — the original CJC-1295 was the DAC-bearing molecule, and the name was retrospectively applied to the un-modified peptide by vendors. So the more accurate name, Mod GRF 1-29, is the less common one, and the ambiguous name won.

Practically, this means you cannot resolve the ambiguity by reasoning about which is “the real” CJC-1295. Look at the vial label or the certificate of analysis, or ask whoever wrote your instructions whether DAC is present. Instructions that say “CJC-1295” without saying which form do not contain enough information to follow.

The vial arithmetic cannot tell them apart

Reconstitution maths only knows milligrams and millilitres, so it is identical whichever compound is in the vial:

• 2 mg vial with 2 mL of water: 2 ÷ 2 = 1 mg/mL, or 10 mcg per unit on a U-100 syringe
• 5 mg vial with 2 mL of water: 5 ÷ 2 = 2.5 mg/mL, or 25 mcg per unit on a U-100 syringe

Enter the dose and concentration from your clinician, pharmacy, product instructions, or research protocol; divide the dose by the mcg per unit and the result is the number of units. VialPal handles the math. What it cannot do is tell you which CJC-1295 is in the vial — only the label can. If the draw your instructions imply looks wildly different from what you expected, or does not fit the syringe you reached for, stop and confirm which form the instructions mean. The calculator shows the draw size and the doses per vial side by side for exactly this reason.

The half-life difference is not only about convenience

The two forms are easy to read as the same thing in two strengths. They are not: they produce different exposure profiles, and this is one of the few places in this space where published human data describes the difference rather than convention asserting it.

Growth hormone is normally secreted in pulses rather than held at a steady level. A short-acting GHRH analogue raises a pulse and then clears; a DAC-bound one keeps levels elevated across days. Whether the pulsatile pattern persists under that continuous stimulation is precisely what the published CJC-1295 work set out to measure, and that is the substantive difference between the two. Neither form has an established human dose or schedule, so the useful conclusion is that they are not interchangeable — not that either is the one to pick.

What to record

Log the DAC status in the entry itself, not just in your memory of which vial is which. “CJC” alone is ambiguous the moment you own both. “CJC no-DAC” with the microgram amount, the unit count, “at 1 mg/mL” and “vial opened 3 Aug” is not.

Give every compound its own entry under its exact name, so no record depends on remembering what an abbreviation meant. Half-lives, vial sizes and storage for both forms are listed side by side in the library.