CJC-1295 is a synthetic analog of growth hormone releasing hormone, specifically the first 29 amino acids of GHRH. Two versions circulate under the same name, and they behave almost nothing alike. One carries a Drug Affinity Complex (DAC) and lasts the better part of a week. The other has no DAC, is really Modified GRF 1-29, and is gone in half an hour. If you have ever been confused about why one protocol says inject once a week and another says inject three times a day, this is why. Everything below is research-use-only context. There is no approved human indication for CJC-1295, and the dosing figures here are practice-based, not label-derived. None of this is medical advice.
What the DAC does
The DAC is a maleimidoproprionic acid group attached to the peptide. After a subcutaneous injection it forms a covalent bond with albumin, the most abundant protein in your blood. Albumin has a long residence time, so anything tethered to it gets dragged along and is protected from the enzymes and kidneys that would otherwise clear a small peptide within minutes. The practical result is a bioconjugate that keeps stimulating the pituitary for days on a single dose.
The human pharmacokinetic data comes from a first-in-man study in healthy adults. Single subcutaneous doses raised mean plasma GH by 2 to 10 fold for 6 days or more, raised IGF-1 by 1.5 to 3 fold for 9 to 11 days, and the estimated half-life came out at 5.8 to 8.1 days (Teichman 2006, J Clin Endocrinol Metab, PMID 16352683). Doses in that program spanned the low microgram-per-kilogram range up through 30 and 60 mcg/kg in the repeat-dose arms. Treat the exact per-kilogram figures as study-specific rather than a dosing recommendation.
Strip the DAC off and you are left with Mod GRF 1-29, which is the same GHRH(1-29) sequence with a few stabilizing amino acid substitutions but no albumin anchor. Its half-life is on the order of 30 minutes. It produces a short, sharp GH pulse and then clears.
Why the dosing frequency is completely different
This is the whole point of the DAC vs no-DAC split, so it is worth being explicit.
A drug's half-life sets how often you have to redose to keep it working. CJC-1295 with DAC has a half-life measured in days, so one injection covers most of a week. That is why DAC protocols are built around roughly 1 to 2 injections per week. You are topping up a slow-draining reservoir, not chasing a pulse.
Mod GRF 1-29 (no DAC) has a half-life of about 30 minutes, so a single dose does its job and disappears before your next meal. To get repeated GH release you have to inject repeatedly, which is why no-DAC protocols run multiple times a day, often two to four injections. That is also why it is almost always paired with a growth hormone releasing peptide like ipamorelin: the short GHRH pulse plus a GHRP produces a larger, more natural-looking burst of GH than either alone, and the brevity of the pulse is considered a feature, since it tries to mimic the body's own episodic GH rhythm rather than flatten it out.
So the two molecules represent two philosophies. DAC pushes GH and IGF-1 to a sustained, elevated plateau for days. No-DAC pushes a series of brief pulses. Neither is inherently better; they are doing different things. If your reference material talks about mimicking natural pulsatility, it is describing the no-DAC approach. If it talks about a steady multi-day elevation from a weekly shot, it is describing DAC. For more on how half-life maps to dosing frequency in general, see the peptide half-life and dosing frequency guide.
The naming confusion (this trips up almost everyone)
Here is the mess. A large share of product sold as "CJC-1295" or even "CJC-1295 no DAC" is actually Mod GRF 1-29, the short-acting molecule. The name "CJC-1295" strictly refers to the DAC-bearing bioconjugate from the original research, but the market has applied the label loosely to both. When someone says they run "CJC-1295 with ipamorelin three times a day," they are almost certainly using no-DAC Mod GRF 1-29, because dosing the true DAC version that often would make no pharmacological sense given its multi-day half-life.
This site has two separate calculators for exactly this reason:
- The CJC-1295 calculator is for the standalone long-acting DAC molecule, dosed weekly.
- The CJC-1295 / ipamorelin calculator is for the popular blend, which pairs short-acting Mod GRF 1-29 with ipamorelin and is dosed daily.
They are not interchangeable. Picking the wrong one will give you the wrong injection frequency and the wrong syringe volume. Before you draw anything up, confirm which molecule is actually in your vial.
Community research dosing for CJC-1295 DAC
To be clear one more time: there is no approved label for CJC-1295, so the numbers below are practice-based figures reported in research and hobbyist communities, not clinically validated doses.
For the DAC version, weekly totals reported in that setting land roughly in the 500 to 2000 mcg per week range. Common patterns look like:
- A single weekly injection of around 1000 to 2000 mcg.
- A split of the weekly total into two injections, for example 500 mcg twice weekly, on the theory that it smooths the peak-to-trough swing.
Because the half-life is so long, there is a documented cumulative effect: levels build over the first few weeks of repeated dosing before settling. That is another reason DAC protocols tend to start conservative and hold steady rather than escalating quickly.
For no-DAC Mod GRF 1-29, the picture is different. Doses are smaller per shot, commonly around 100 mcg, and given two to four times daily, frequently alongside ipamorelin, timed around waking, workouts, and bedtime to line up with natural GH windows.
Reconstitution and the syringe math
CJC-1295 ships as a lyophilized powder and has to be reconstituted with bacteriostatic water before use. The arithmetic is the same regardless of DAC status; only the dose and frequency change.
Take a 2 mg vial and add 2 ml of bacteriostatic water:
- 2 mg / 2 ml = 1 mg/ml = 1000 mcg per ml
- 1000 mcg = 1 ml = 100 units on a U-100 insulin syringe
- 500 mcg = 0.5 ml = 50 units
- 250 mcg = 0.25 ml = 25 units
- 100 mcg = 0.1 ml = 10 units
So if your weekly DAC dose is 1000 mcg as a single shot, that is a full 1 ml, or 100 units. If you split it into 500 mcg twice weekly, that is 50 units each time.
To reconstitute cleanly:
- Wipe both vial stoppers with an alcohol swab.
- Draw 2 ml bacteriostatic water into a 3 ml syringe.
- Angle the needle so the water runs down the inside glass wall rather than blasting straight onto the powder, which foams and can shear the peptide.
- Let it sit a few minutes, then swirl gently, never shake, until the solution is clear.
- Store refrigerated at 2 to 8 C. The common 28-day refrigerated rule of thumb comes from Bacteriostatic Water for Injection labeling and USP beyond-use conventions, not peptide-specific stability trials.
If insulin syringe units are new to you, the insulin syringe guide walks through how units map to milliliters. And rather than doing the math by hand every time, plug your vial size and target dose into the CJC-1295 calculator to get the exact unit mark.
Which one fits which goal
A quick way to keep the two straight:
| CJC-1295 with DAC | Mod GRF 1-29 (no DAC) | |
|---|---|---|
| Half-life | ~6 to 8 days | ~30 minutes |
| Injection frequency | ~1 to 2x per week | 2 to 4x per day |
| GH profile | Sustained multi-day elevation | Brief pulses |
| Usual pairing | Often run solo | Almost always with a GHRP (e.g. ipamorelin) |
| Calculator | CJC-1295 | CJC-1295 / ipamorelin |
The DAC version trades pulsatility for convenience and a steady state. The no-DAC version trades convenience for a pulse pattern that more closely tracks physiological GH release. Which matters to a given research question depends on whether the endpoint is sustained IGF-1 exposure or the shape of the GH pulse itself.
The bottom line
The "DAC" in CJC-1295 is not a minor variant. It is an albumin-binding group that turns a 30-minute peptide into a 6-to-8-day one, and that single change flips the dosing from several times a day to once or twice a week. Most of the confusion in this space comes from vendors labeling short-acting Mod GRF 1-29 as "CJC-1295," so the first step in any protocol is confirming which molecule you actually have and picking the matching calculator. All dosing here is research-use-only and practice-based; there is no approved human indication, and none of this is medical advice. Talk to a qualified healthcare professional before acting on any of it.
References
- Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. "Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults." J Clin Endocrinol Metab, 2006. PMID 16352683. https://pubmed.ncbi.nlm.nih.gov/16352683/