CJC Peptide: Which CJC-1295 Are You Holding?

Both versions start from the same 29-amino-acid fragment of growth hormone-releasing hormone, carrying four amino acid substitutions that block the DPP-IV enzyme from chewing it apart in the bloodstream. That shared backbone is why they share a name.

The DAC version adds one thing: a Drug Affinity Complex, a maleimidopropionyl group hung off a C-terminal lysine (Jetté et al., Endocrinology, 2005). Once injected, that group latches onto a free thiol on serum albumin and stays there.

Picture a dog and a long leash staked into the ground. Without the leash, the peptide wanders off within half an hour: filtered, degraded, gone. The DAC is the leash, and albumin is the stake. The peptide cannot leave circulation, so it keeps signalling the pituitary for days. Literally: the DAC group forms a covalent bond with albumin, the most abundant protein in plasma, and the peptide's measured half-life stretches to 5.8-8.1 days (Teichman et al., J Clin Endocrinol Metab, 2006).

Strip the DAC off and you have Mod GRF (1-29), also written Modified GRF 1-29 or "CJC-1295 no DAC." Same four substitutions, no tether, roughly 30 minutes of activity. The molecular weights differ accordingly: 3647.15 g/mol for the DAC version, 3367.9 g/mol for Mod GRF (1-29).

Both versions bind the GHRH receptor on pituitary somatotrophs, the same receptor natural GHRH uses. Neither one contains growth hormone. They ask the pituitary to release its own, which is why the ceiling on the response is your own somatotroph capacity.

Sustained stimulation does not flatten your GH rhythm the way many forum posts claim. In healthy adults given CJC-1295, GH pulse frequency and amplitude were unchanged; what rose was the trough between pulses, by 7.5-fold, along with a 45% increase in IGF-1 (Ionescu & Frohman, J Clin Endocrinol Metab, 2006). The DAC version lifts the floor rather than the peaks.

Ipamorelin sits in a different pharmacological family and gets confused with CJC constantly, largely because blends are sold as a single product labelled "CJC/Ipa." Ipamorelin is a pentapeptide that activates the ghrelin receptor (GHS-R1a), and it does so selectively: at doses more than 200-fold above its GH-releasing threshold it left ACTH, cortisol, prolactin, LH, FSH and TSH untouched (Raun et al., Eur J Endocrinol, 1998).

Two receptors, two doors, one room. That is the entire rationale for the stack, and the reasons it works are laid out in CJC-1295 and ipamorelin benefits, with the trade-offs in CJC-1295 and ipamorelin side effects.

These are the two failures that follow directly from not knowing which vial you own. Both are common, and both are quantifiable.

Nobody teaches this, so buyers guess. Four signals, in descending order of reliability.

1. The certificate of analysis. Every legitimate supplier publishes one per batch. Look for molecular weight. 3647.15 g/mol (C165H269N47O46) is CJC-1295 with DAC. 3367.9 g/mol (C152H252N44O42) is Mod GRF (1-29), the no-DAC version. If no COA exists, you do not know what you bought.

2. The label wording. "CJC-1295 DAC," "CJC-1295 with DAC," and "CJC-1295 (DAC)" mean the tethered version. "CJC-1295 no DAC," "CJC-1295 w/o DAC," "Mod GRF (1-29)," and "Modified GRF 1-29" all mean the 30-minute version. A bare "CJC-1295" with no qualifier is most often the DAC version, and betting on "most often" is how scenario 2 happens.

3. Vial size. DAC is commonly sold in 2 mg vials because 2 mg is one weekly dose. Mod GRF ships in 5 mg and 10 mg vials, because at 100 mcg per injection a 5 mg vial carries 50 doses. A 10 mg vial of "CJC-1295" is almost never DAC.

4. Price per milligram. DAC carries the extra synthesis step and prices higher per milligram. When a 5 mg "CJC-1295" vial costs less than a 2 mg one, you are looking at Mod GRF. Run the numbers with the peptide cost calculator.

Blends deserve their own warning. "CJC ipa peptide," "CJC/Ipa," and "CJC-1295 + Ipamorelin 5mg" are premixed vials, and the split is rarely printed. A 5 mg blend might be 2 mg CJC and 3 mg ipamorelin, or the reverse. Blends almost always use the no-DAC version, since the pairing depends on synchronised pulses. Ask the vendor for the ratio in writing, then dose from the CJC-1295 + Ipamorelin dosage calculator rather than the vial's total milligrams.

Once identified, reconstitution is the same procedure for both: same bacteriostatic water, same technique, different volumes. Work through the peptide reconstitution calculator, then refrigerate. Reconstituted vials of either version hold potency about 21 to 28 days at 2-8°C (how long reconstituted peptides last).

Four of these five are GHRH analogues. Ipamorelin is the outlier, and the table is the fastest way to see why the stack pairs the two classes.

Mod GRF (1-29) is sermorelin with four amino acids swapped for protease resistance, which is why it outlasts sermorelin by roughly a factor of two while doing the same job. The comparison is worked through in CJC-1295 vs sermorelin.

Tesamorelin is the only member with a completed approval and an indication behind it, and the only one whose fat-loss effect has been measured against placebo in a registration trial. If the visceral fat question is what brought you here, read tesamorelin vs CJC-1295 before ordering anything.

The claimed benefits of the CJC peptide family follow from raising GH and IGF-1: deeper slow-wave sleep, improved body composition, faster soft-tissue recovery, better skin quality. The measured evidence is thinner than the marketing.

What human data exists: a single injection of CJC-1295 with DAC raised mean plasma GH 2- to 10-fold for 6 days or more and IGF-1 1.5- to 3-fold for 9 to 11 days, with IGF-1 staying above baseline for up to 28 days after multiple doses, and no serious adverse reactions at 30 or 60 mcg/kg (Teichman et al., J Clin Endocrinol Metab, 2006). That is a pharmacodynamic result. It shows the peptide does what it is supposed to do to a hormone level. No trial has taken it further and shown that the hormone change produces fat loss, muscle gain, or improved sleep in healthy adults.

Neither version of CJC-1295 has ever been approved by the FDA for any indication. Both CJC-1295 and ipamorelin acetate were added to Category 2 of the interim 503A bulks list in September 2023, the bin for substances FDA considers to present significant safety risks in compounding. Both were removed from Category 2 in September 2024 after their nominators withdrew the nominations, and a December 2024 FDA advisory committee voted against adding CJC-1295 to the 503A bulks list. Removal from Category 2 is not approval, and it is not permission to compound. The compound sits in regulatory limbo, sold legally only as a research chemical.

Read the FDA peptide crackdown for the current landscape and the peptide safety guide for contraindications. Active malignancy, pregnancy, pituitary disease, and diabetic retinopathy rule out GH peptides entirely.

1. Reading a protocol without checking which version it describes. A "2 mg" instruction is correct for DAC and a 20-fold overdose for Mod GRF. Verify the version before you copy any number, then verify your own vial.

2. Assuming a blend is DAC. Premixed CJC/Ipa vials use the no-DAC version because the stack depends on both peptides peaking together at 15 to 30 minutes. Dosing a blend weekly gives you three hours of activity per week.

3. Treating ipamorelin as a CJC variant. It works through the ghrelin receptor rather than the GHRH receptor, and it cannot substitute for either CJC version. Adding it does not change your CJC dose. The peptide stacking guide explains what combines and what merely overlaps.

4. Buying on price without a certificate of analysis. A cheap 10 mg "CJC-1295" vial is Mod GRF (1-29) roughly every time. The COA settles it in ten seconds by molecular weight. Store whichever you get correctly from day one (how to store peptides).