CJC-1295 Dosage and Reconstitution: What the Research Literature Actually Reports

CJC-1295 is a synthetic peptide analog of the first 29 amino acids of human growth hormone-releasing hormone (GHRH, also written GRF). Native GHRH is the hypothalamic signal that prompts the pituitary to release growth hormone in pulses. Because native GRF(1-29) is degraded within minutes by the enzyme dipeptidyl peptidase-4 (DPP-4) and by other proteases, researchers engineered analogs that resist this breakdown and, in one version, remain in circulation far longer.

The molecule carries four amino acid substitutions relative to native GRF(1-29): D-Ala at position 2, Gln at position 8, Ala at position 15, and Leu at position 27. These changes reduce enzymatic cleavage and oxidation, which is why even the shorter-acting form is more stable than unmodified GHRH. This substituted backbone is often called Modified GRF 1-29 or Mod GRF (1-29).

The term that causes the most confusion is DAC, which stands for Drug Affinity Complex. In the DAC version, the peptide is fitted with an additional lysine linker bearing a maleimidopropionyl group. Once injected, this reactive group forms a covalent bond with circulating serum albumin, effectively turning the peptide into a long-lived albumin conjugate. This bioconjugation strategy is what dramatically extends the half-life, as described in the foundational work by Jetté and colleagues.

So when suppliers list CJC-1295 with DAC versus CJC-1295 without DAC, they are describing two pharmacologically distinct research materials that happen to share the same peptide backbone. The version without DAC is chemically the Modified GRF 1-29 peptide. The version with DAC is that same sequence plus the albumin-binding complex. For deeper background on how peptides are classified and how modifications change their behavior, see our overview of what peptides are and the dedicated CJC-1295 monograph.

This section is educational and describes research findings only. It is not medical guidance and does not imply any human use.

The half-life difference between the two formulations is the single most important concept to understand, because it explains why research protocols for the two versions look nothing alike. This is a documentation point, not a dosing recommendation.

For the DAC version, Teichman and colleagues (2006) reported that a single subcutaneous administration in healthy adults produced sustained elevations in growth hormone and insulin-like growth factor 1 (IGF-1) for extended periods, with a plasma half-life on the order of several days (commonly cited as roughly 6 to 8 days). Because the peptide is anchored to albumin, it is not cleared quickly, and the studied administration frequency was infrequent, often once weekly or a small number of times per week in the published pharmacokinetic work.

For the non-DAC version (Modified GRF 1-29), there is no albumin anchor. It behaves like a short-acting GHRH analog with a circulating half-life measured in minutes, frequently described as around 30 minutes. In research contexts this short window is the whole point: it produces a brief, sharp GH pulse that mimics the body's natural pulsatile secretion and then clears. That short duration is why non-DAC protocols in the literature involve much more frequent administration than DAC protocols.

A second nuance comes from Ionescu and Frohman (2006), who examined whether continuous GHRH-analog stimulation flattens the natural pulsatility of growth hormone. Their finding, that pulsatile GH secretion persisted even under continuous CJC-1295 exposure, is central to how researchers think about the trade-offs between a long, steady signal (DAC) and a brief, pulse-like signal (no-DAC).

Understanding this split matters before any reconstitution math, because the amount you dissolve and the way you divide a vial depend entirely on which molecule you are handling. Researchers frequently pair the non-DAC version with other compounds only after understanding these kinetics; see our peptide stacking guide for how combinations are documented.

Reconstitution is the process of dissolving a freeze-dried (lyophilized) peptide powder into a liquid so it can be measured accurately. CJC-1295 is shipped as a white lyophilized powder inside a sealed vial precisely because peptides are far more stable dry than in solution. The reconstitution step is where most measurement errors originate, so the underlying principle is worth stating plainly.

The governing relationship is simple: concentration equals mass divided by volume. If a vial contains 2 mg of peptide and you add 2 mL of solvent, the resulting concentration is 1 mg per mL, which is 1000 micrograms (mcg) per mL. Add 1 mL instead, and the same 2 mg vial yields 2 mg/mL. The mass in the vial never changes; only the volume of solvent you add determines how concentrated the final solution is.

The standard solvent used in the research literature and by suppliers is bacteriostatic water (sterile water containing 0.9 percent benzyl alcohol), which inhibits microbial growth and allows a multi-use vial to be accessed repeatedly over a period of days. Sterile water without a preservative is sometimes used but does not offer the same protection for repeated access. The choice of a larger or smaller solvent volume is largely a matter of convenience: more water makes each unit on the syringe less concentrated and therefore easier to measure in small amounts, while less water concentrates the solution.

Technique protects the molecule. The solvent should be introduced slowly, letting it run down the inside wall of the vial rather than shooting directly onto the powder pellet. The vial is then gently swirled, never shaken, because vigorous agitation and foaming can shear and denature the fragile peptide chain. A properly reconstituted solution is clear and colorless; visible cloudiness, particulates, or discoloration are signals that the material should not be used.

Before performing any calculation, decide your target concentration and write it down. A dedicated reconstitution calculator removes arithmetic mistakes by letting you enter vial strength, solvent volume, and your intended amount, then returning the exact number of syringe units. Using a tool for this step is one of the simplest ways to reduce error.

Peptide research protocols are almost always drawn with a U-100 insulin syringe, and the unit markings on that syringe are the source of most confusion. The critical fact is that these units are volume markings, not a measure of peptide mass. On a U-100 syringe, 100 units equal 1 mL, which means each single unit is 0.01 mL and each 10-unit mark is 0.1 mL.

The conversion always runs through concentration. First establish how much peptide sits in one unit of your solution. Take your concentration in micrograms per mL and divide by 100. For example, a 2 mg vial reconstituted with 2 mL of bacteriostatic water gives 1000 mcg/mL, and dividing by 100 tells you each unit holds 10 mcg. To draw a target amount, divide the target by the amount per unit.

Worked example: with the solution above (10 mcg per unit), a target of 100 mcg requires 100 divided by 10, which is 10 units on the syringe (0.1 mL). A target of 50 mcg requires 5 units. If you had instead added only 1 mL of water to the same 2 mg vial, the concentration would double to 2000 mcg/mL, each unit would carry 20 mcg, and that same 100 mcg target would now be just 5 units. The peptide amount is identical; only the syringe reading changes.

Two practical rules follow. First, always confirm your syringe is genuinely U-100, because U-40 and U-50 syringes exist and would silently corrupt every calculation. Second, favor a solvent volume that puts your intended amount in an easily read range on the barrel, roughly 10 to 30 units, so that small hand tremors translate into small errors rather than large ones. The numbers above are illustrative arithmetic examples only and are not a suggested protocol. When in doubt, verify with the Peptide Lab calculator rather than doing the math under pressure.

This section documents figures that appear in published pharmacokinetic studies. It is provided strictly to describe the scientific record. It is not a recommended dosage, and CJC-1295 is not approved for human therapeutic use in any jurisdiction we are aware of.

In the pivotal human pharmacokinetic study of the DAC version, Teichman and colleagues (2006) administered single subcutaneous doses to healthy adults and reported dose-dependent, sustained increases in growth hormone and IGF-1. The doses studied were defined on a per-kilogram basis in escalating cohorts, and the notable observation was duration: a single administration influenced GH and IGF-1 levels for many days, consistent with the albumin-binding mechanism. This is why DAC pharmacokinetic protocols cluster around infrequent administration rather than daily dosing.

For the non-DAC version, the literature is oriented around its short half-life. Because Modified GRF 1-29 clears within minutes, research discussions emphasize timing a brief GH pulse rather than maintaining a plateau. The frequency studied is therefore much higher than for the DAC form, and the effect is evaluated as an acute secretory response rather than a sustained elevation. Ionescu and Frohman (2006) contributed the important observation that pulsatile GH secretion is preserved under GHRH-analog stimulation, which shapes how researchers interpret both formulations.

Preclinical work rounds out the picture. Studies in GHRH-deficient mouse models demonstrated that once-daily administration of the long-acting analog could normalize growth parameters, and the bioconjugate chemistry underpinning the DAC approach was validated in the receptor-activation work of Jetté and colleagues. These animal and mechanistic studies are the backbone of what is actually known, and they are explicitly distinct from any human therapeutic evidence.

The honest summary is that robust, approved human dosing guidance does not exist for CJC-1295. What exists is a modest set of early-phase pharmacokinetic studies plus preclinical data. Anyone reading dosing figures online should recognize that they are typically extrapolations from these limited sources, not established clinical recommendations. For how to read the difference between animal data and human evidence generally, our medical disclaimer and the CJC-1295 guide provide additional context.

Storage conditions determine how long a peptide retains its integrity, and the rules differ sharply between the dry powder and the reconstituted solution. Understanding both states helps explain why proper handling matters as much as accurate math.

In its lyophilized (powder) form, CJC-1295 is relatively robust. Sealed vials are generally kept refrigerated and, for longer horizons, frozen, protected from light and moisture. The absence of water is what confers this stability, because most peptide degradation pathways require a solvent to proceed. Many suppliers note that unopened lyophilized vials remain stable for extended periods under cold storage.

Once reconstituted, the situation changes. The peptide is now in solution and should be refrigerated at roughly 2 to 8 degrees Celsius. Using bacteriostatic water rather than plain sterile water extends the usable window because the benzyl alcohol preservative suppresses microbial growth during repeated vial access. Even so, a reconstituted solution has a finite shelf life, commonly discussed in the range of a few weeks under refrigeration, after which peptide integrity can decline.

Several environmental factors accelerate degradation and should be minimized. Repeated freeze-thaw cycles of a reconstituted solution are particularly damaging and are best avoided entirely. Exposure to light, heat, and vigorous agitation all contribute to breakdown. The vial should be returned to the refrigerator promptly after each access, and the rubber stopper should be wiped with an alcohol swab before every draw to preserve sterility.

A practical habit is to label each reconstituted vial with the date it was mixed and the concentration, so that both the age of the solution and the syringe math are unambiguous later. This small step prevents the common situation of an unlabeled vial of uncertain strength and age, which is a frequent source of both dosing error and wasted material.

Most problems with research peptides are not exotic; they are predictable arithmetic and handling mistakes. Cataloguing them is one of the most useful things this article can do, because each error has a simple preventive habit.

The most frequent error is confusing units of volume with units of mass. A researcher reads that a protocol calls for a certain number of micrograms, then draws that number of syringe units without converting through concentration. Because a syringe unit is a fixed 0.01 mL of volume, its microgram content depends entirely on how the vial was reconstituted. Skipping the conversion can produce an amount that is off by an order of magnitude.

Other recurring mistakes include the following:

• Using the wrong syringe scale. U-40 or U-50 syringes have different volume-per-unit relationships than U-100, so an unchecked syringe type silently invalidates every calculation.
• Forgetting which formulation is in the vial. Treating a DAC vial like a non-DAC vial, or the reverse, ignores the enormous half-life difference and misrepresents the entire protocol being documented.
• Shaking instead of swirling. Vigorous agitation foams and shears the peptide, degrading it before the first draw.
• Squirting solvent directly onto the powder. Directing the stream against the vial wall protects the pellet from mechanical stress.
• Reusing degraded solution. Cloudy, discolored, or particulate-containing solutions, or solutions kept past a sensible window, should be discarded rather than used.
• Not accounting for net peptide content. Labeled milligrams may include counter-ions or salt; assuming absolute purity can slightly overstate the actual peptide mass.

The single most powerful safeguard is to remove mental arithmetic from the moment of drawing. Calculate concentration and target units in advance, write them on the vial label, and verify with a dedicated calculator. A second useful habit is to keep a written log of vial strength, solvent volume, reconstitution date, and each draw, which makes any discrepancy visible early. Consistency in tooling and record-keeping prevents nearly all of the errors above.

Any discussion of CJC-1295 dosing is incomplete without a clear statement of its regulatory and safety status. This is the YMYL (Your Money or Your Life) heart of the article, and it deserves to be unambiguous.

CJC-1295 is not approved by the FDA, the EMA, or, to our knowledge, any comparable regulator for human therapeutic use. It is sold and handled as a research compound, typically labeled for research use only. Its legal status varies by jurisdiction, and possession, sale, or use may be restricted or regulated differently depending on where you are. It is also a monitored substance in the context of anti-doping, since growth hormone secretagogues fall under the relevant prohibited-substance categories in sport.

The human safety data are correspondingly thin. The published human studies are early-phase and small, designed to characterize pharmacokinetics rather than to establish a long-term safety profile. Consequently, the long-term risks of GHRH-analog administration in humans are not well defined, and claims of a benign safety profile are not supported by robust evidence. Because these compounds raise growth hormone and IGF-1, questions about effects on glucose metabolism, fluid retention, and other systems are scientifically reasonable and remain inadequately answered.

Quality is a further concern with research-grade material. Purity, actual peptide content, and sterility can vary between sources, and mislabeling of DAC versus non-DAC material or of vial strength is a documented risk in the gray market. None of the arithmetic in this article can compensate for a vial whose true contents differ from its label.

For all of these reasons, the responsible framing is documentation, not instruction. This article describes what the research literature reports about half-life, reconstitution, and measurement. It does not recommend that anyone administer CJC-1295, and it does not provide a human dosage. If you are considering anything related to growth hormone physiology for a health reason, consult a qualified healthcare professional. This content is for educational purposes only. Review our full medical disclaimer before drawing any conclusions.