What Is CJC-1295? (The Same Peptide, Two Different Forms)
Research labs ordering CJC-1295 often assume they're getting one compound. Then receive two options with starkly different half-lives. CJC-1295 with DAC (Drug Affinity Complex) extends growth hormone-releasing hormone (GHRH) activity for 6–8 days through albumin binding, while CJC-1295 without DAC. Often called Mod GRF 1-29. Clears plasma in approximately four hours. Both are synthetic analogs of the naturally occurring GHRH 1-29 fragment, modified at position 2 (alanine replaced with D-alanine), position 8 (glutamine substituted for alanine), position 15 (alanine replaced with leucine), and position 27 (arginine changed to leucine). The DAC variant adds a reactive lysine group at position 30 that covalently binds to serum albumin, creating a depot effect that fundamentally alters dosing strategy.
Our team has guided research institutions through this exact specification process. The gap between ordering the right peptide and ordering the wrong one comes down to understanding what 'CJC-1295' actually means. And that clarity starts with the DAC distinction.
What is the difference between CJC-1295 with DAC and CJC-1295 without DAC?
CJC-1295 with DAC is a long-acting GHRH analog with a half-life of approximately 6–8 days, requiring dosing once or twice weekly. CJC-1295 without DAC (Mod GRF 1-29) has a half-life of roughly 30 minutes and clears within four hours, necessitating multiple daily administrations for sustained effect. Both stimulate pituitary growth hormone release through GHRH receptor binding, but the DAC modification creates albumin conjugation that extends plasma retention 40–50 times longer than the non-DAC variant.
The confusion around whether CJC-1295 is 'the same as' CJC-1295 stems from inconsistent nomenclature across suppliers. Some vendors label Mod GRF 1-29 as 'CJC-1295' without clarifying the absence of DAC, leading researchers to assume they're comparing identical compounds. They're not. The molecular structure differs at position 30, the pharmacokinetics differ by an order of magnitude, and the dosing protocols differ entirely. This article covers the structural modifications that define both variants, the albumin-binding mechanism that distinguishes DAC from non-DAC versions, and the practical implications for research design when selecting between the two.
The Core Peptide Structure: What CJC-1295 and CJC-1295 Share
Both CJC-1295 with DAC and CJC-1295 without DAC are derived from the first 29 amino acids of human growth hormone-releasing hormone (GHRH 1-29), the endogenous peptide that binds to GHRH receptors on anterior pituitary somatotrophs to stimulate growth hormone secretion. Native GHRH 1-29 has a plasma half-life of approximately 7 minutes due to rapid enzymatic degradation by dipeptidyl peptidase-4 (DPP-4) at the N-terminus and endopeptidases throughout the sequence. To extend biological activity, researchers introduced four strategic amino acid substitutions that create the modified GHRH analog now known generically as CJC-1295.
The modifications include: replacing alanine at position 2 with D-alanine (a non-natural amino acid resistant to DPP-4 cleavage), substituting glutamine at position 8 with alanine (reducing aggregation during synthesis), changing alanine at position 15 to leucine (enhancing receptor binding affinity), and replacing arginine at position 27 with leucine (improving stability against proteolytic degradation). These substitutions increase the peptide's resistance to enzymatic breakdown from 7 minutes to approximately 30 minutes in vivo. A fivefold improvement but still insufficient for practical once-daily dosing.
This 29-amino-acid modified GHRH sequence forms the structural foundation for both DAC and non-DAC variants. The term 'CJC-1295' technically refers only to the DAC-modified version developed by ConjuChem Biotechnologies in the early 2000s, but research peptide suppliers frequently use 'CJC-1295' as shorthand for the base 29-amino-acid sequence regardless of DAC presence. That nomenclature ambiguity is the source of confusion when researchers ask whether CJC-1295 is the same as CJC-1295. The answer depends on whether the DAC modification is present.
The DAC Modification: How One Lysine Changes Everything
The Drug Affinity Complex (DAC) modification adds a single reactive lysine residue at position 30 of the peptide chain, engineered to form a covalent bond with circulating serum albumin through maleimide chemistry. Albumin, the most abundant plasma protein (35–50 g/L in human serum), acts as a physiological depot for lipophilic and weakly basic compounds. By attaching to albumin, CJC-1295 with DAC achieves a half-life extension from 30 minutes to 6–8 days. Approximately 300 times longer than the unmodified analog.
This albumin binding is irreversible once formed. The lysine-maleimide linkage creates a stable amide bond that persists for the duration of albumin's own half-life (approximately 19–21 days in humans). As the albumin-CJC-1295 complex circulates, the peptide is gradually released through slow dissociation kinetics, maintaining steady-state plasma levels for nearly a week after a single subcutaneous injection. Research published in the Journal of Clinical Endocrinology & Metabolism demonstrated that CJC-1295 with DAC administered at 30 or 60 mcg/kg produced sustained elevations in serum growth hormone and IGF-1 levels for up to 14 days, with peak GH pulses occurring 2–4 hours post-injection and smaller pulses persisting throughout the dosing interval.
CJC-1295 without DAC. Mod GRF 1-29. Lacks position 30 entirely. It terminates at leucine-29, meaning it cannot form albumin conjugates. Plasma clearance follows first-order kinetics with a half-life of approximately 30 minutes, and biological activity ceases within 3–4 hours. To maintain pulsatile GH stimulation comparable to DAC variants, researchers must administer non-DAC CJC-1295 two to three times daily, typically paired with a growth hormone secretagogue like GHRP-2, GHRP-6, or ipamorelin to amplify the GH pulse.
CJC-1295 (No DAC) vs CJC-1295 (With DAC): Research Application Comparison
Half-Life
~30 minutes
6–8 days
The DAC modification extends retention by 300× through albumin binding
Dosing Frequency
2–3× daily
1–2× weekly
Non-DAC requires frequent administration to sustain GH pulses
Peak GH Pulse Timing
15–30 minutes post-injection
2–4 hours post-injection, with smaller pulses for 6–8 days
Non-DAC produces sharp, brief pulses; DAC produces sustained elevation
Typical Research Dose Range
100–200 mcg per administration
30–60 mcg/kg weekly or biweekly
Non-DAC uses lower absolute doses but higher frequency
Common Pairing Strategy
Often combined with GHRP-2, GHRP-6, or ipamorelin for synergistic GH release
Used alone or with growth hormone secretagogues
Non-DAC benefits from secretagogue co-administration
Primary Advantage
Mimics natural pulsatile GH release pattern without long-term accumulation
Convenient dosing with sustained IGF-1 elevation
DAC suits compliance-focused protocols; non-DAC suits pulsatile studies
What If: CJC-1295 Research Scenarios
What If I Receive CJC-1295 Without DAC Confirmation — How Do I Verify Which Version I Have?
Request the supplier's certificate of analysis (CoA) showing molecular weight via mass spectrometry. CJC-1295 with DAC has a molecular weight of approximately 3647 Da due to the additional lysine-maleimide complex at position 30. CJC-1295 without DAC (Mod GRF 1-29) has a molecular weight of approximately 3367 Da, reflecting the absence of position 30. A 280 Da difference confirms which variant you received. If the supplier cannot provide mass spec data, the peptide's provenance is questionable. Reputable research suppliers always include CoA documentation showing HPLC purity and MS-confirmed molecular weight.
What If I Need Sustained Growth Hormone Elevation for a Multi-Week Study — Which Variant Is Better?
CJC-1295 with DAC is the more practical choice for sustained IGF-1 elevation across multi-week protocols. A single subcutaneous injection maintains elevated growth hormone pulsatility for 6–8 days, reducing handling frequency and minimizing stress-induced variables in animal models. Non-DAC CJC-1295 requires 2–3 daily injections to maintain comparable GH stimulation, which increases technical complexity and introduces circadian rhythm confounds if dosing times vary. For studies measuring cumulative anabolic effects (lean mass accretion, bone density, metabolic markers), DAC provides more consistent baseline conditions.
What If I Want to Study Acute Growth Hormone Pulses Without Long-Term Accumulation?
CJC-1295 without DAC is the better option for acute pulse studies. It clears plasma within four hours, allowing researchers to measure a single discrete GH release event without overlapping effects from prior doses. This is critical for receptor kinetics studies, dose-response characterization, or experiments examining GH pulse amplitude in response to nutritional or hormonal co-interventions. The short half-life also permits rapid washout between experimental conditions, which DAC variants cannot provide due to their week-long plasma retention.
The Blunt Truth About CJC-1295 Naming Confusion
Here's the honest answer: the peptide research industry uses 'CJC-1295' to describe two fundamentally different compounds, and most suppliers don't clarify which one they're selling unless you ask explicitly. CJC-1295 with DAC is the albumin-binding, long-acting version developed by ConjuChem. That's the original CJC-1295. CJC-1295 without DAC is Mod GRF 1-29, the base 29-amino-acid sequence without the position-30 lysine modification. They share the same core structure but differ in half-life by a factor of 300, dosing frequency by a factor of 14, and practical application entirely.
The confusion persists because 'CJC-1295 no DAC' became industry shorthand even though it's technically a misnomer. The original CJC-1295 patent filing defined the compound as including the DAC modification. Calling Mod GRF 1-29 'CJC-1295 without DAC' is like calling testosterone propionate 'testosterone enanthate without the ester'. The ester is what defines the compound. If a supplier lists 'CJC-1295' without specifying DAC status, assume nothing and request molecular weight confirmation. A 280 Da difference is not a rounding error. It's the difference between a week-long protocol and a thrice-daily injection schedule.
Key Takeaways
CJC-1295 with DAC has a half-life of 6–8 days due to covalent albumin binding at a reactive lysine residue added at position 30, while CJC-1295 without DAC (Mod GRF 1-29) clears plasma in 30 minutes and requires multiple daily doses.
Both variants share the same 29-amino-acid modified GHRH sequence with four strategic substitutions that improve resistance to DPP-4 and endopeptidase degradation compared to native GHRH 1-29.
The DAC modification extends half-life by approximately 300-fold through irreversible maleimide chemistry that links the peptide to serum albumin, creating a sustained-release depot effect.
Research protocols requiring sustained IGF-1 elevation benefit from CJC-1295 with DAC, while acute GH pulse studies require CJC-1295 without DAC to avoid overlapping effects from prior doses.
Verify which variant you received by requesting a certificate of analysis showing molecular weight via mass spectrometry. CJC-1295 with DAC is approximately 3647 Da, while the non-DAC version is approximately 3367 Da.
Most peptide suppliers use 'CJC-1295' ambiguously without clarifying DAC status unless explicitly asked. Always confirm molecular weight and half-life specifications before designing research protocols around either variant.
Our dedication to precision extends across our entire research peptide line. You can explore the synergistic potential of combined protocols with CJC-1295 Ipamorelin 5MG 5MG or discover other compounds like MK 677 and Hexarelin that work through complementary growth hormone pathways. Every peptide in our catalogue undergoes exact amino-acid sequencing and third-party purity verification. The molecular weight matches the specification every time.
The distinction between CJC-1295 with DAC and without DAC isn't academic. It determines whether you dose once weekly or three times daily, whether IGF-1 stays elevated for eight days or four hours, and whether your experimental timeline accommodates a week-long washout or a same-day reset. If a supplier can't tell you which version they're selling, find one who can. Ambiguity at the specification stage compounds into protocol failures downstream.
Frequently Asked Questions
CJC-1295 without DAC is chemically identical to Mod GRF 1-29 — both are the same 29-amino-acid modified GHRH sequence. The term ‘CJC-1295’ originally referred only to the DAC-modified version, but suppliers now use it interchangeably for both variants, leading to nomenclature confusion. If a product is labelled ‘CJC-1295 no DAC,’ it is Mod GRF 1-29.
CJC-1295 with DAC has a half-life of approximately 6–8 days, meaning plasma levels remain elevated for 10–14 days after a single subcutaneous injection. The albumin-bound complex dissociates gradually, maintaining pulsatile growth hormone release throughout the dosing interval. Complete clearance takes 3–4 weeks, though biological activity diminishes significantly after 10–12 days.
Once-daily dosing with CJC-1295 without DAC (Mod GRF 1-29) will produce a single acute GH pulse but will not maintain elevated IGF-1 levels throughout the day. The 30-minute half-life means plasma clearance occurs within 3–4 hours, so growth hormone stimulation ceases until the next dose. Protocols aiming for sustained anabolic signalling require 2–3 daily administrations or a switch to CJC-1295 with DAC.
CJC-1295 with DAC has a molecular weight of approximately 3647 Da due to the lysine-maleimide DAC modification at position 30. CJC-1295 without DAC (Mod GRF 1-29) has a molecular weight of approximately 3367 Da, as it terminates at amino acid position 29. This 280 Da difference is verifiable via mass spectrometry and serves as the definitive confirmation of which variant a researcher has received.
Many peptide suppliers use ‘CJC-1295’ as a generic label for both DAC and non-DAC variants due to widespread industry shorthand, assuming buyers will infer which version based on price or dosing instructions. This creates specification ambiguity that can lead to dosing errors or incorrect study designs. Reputable suppliers always clarify DAC status explicitly and provide molecular weight confirmation in the certificate of analysis.
Yes. Once reconstituted with bacteriostatic water, CJC-1295 with DAC should be refrigerated at 2–8°C and used within 28 days to prevent peptide degradation. Lyophilised (freeze-dried) powder can be stored at −20°C for 12–24 months before reconstitution. Avoid repeated freeze-thaw cycles, as they denature the peptide structure and reduce biological activity.
Published research protocols using CJC-1295 with DAC in human subjects employed doses ranging from 30 to 60 mcg per kilogram of body weight, administered subcutaneously once or twice weekly. A 70 kg subject would receive approximately 2.1–4.2 mg per dose. Animal models use proportionally adjusted doses based on body surface area conversions, not direct mg/kg extrapolation from human studies.
Combining both variants in a single protocol is uncommon because they serve overlapping functions — both stimulate GHRH receptors to release growth hormone. Researchers typically pair CJC-1295 without DAC with a growth hormone secretagogue like GHRP-2 or ipamorelin to amplify the GH pulse, rather than layering two GHRH analogs. Using both would increase cost and complexity without proportional benefit.
CJC-1295 without DAC is preferred in studies examining acute growth hormone pulse dynamics, receptor desensitisation kinetics, or protocols requiring rapid washout between experimental conditions. The short half-life allows researchers to measure discrete GH release events without cumulative effects from prior doses. DAC variants are unsuitable for these applications due to their multi-day plasma retention and overlapping pulse effects.
Request a certificate of analysis (CoA) from the supplier showing HPLC purity percentage (should exceed 98%) and mass spectrometry data confirming molecular weight. The CoA should also include amino acid analysis and endotoxin testing results. Suppliers who cannot provide third-party verified CoAs should be avoided — peptide purity is not verifiable by appearance or solubility alone.