Skip to content
The Peptide Effect
Comparison

CJC-1295 (no DAC) vs CJC-1295 DAC

CJC-1295 (no DAC), also known as Modified GRF 1-29 or MOD-GRF, and CJC-1295 DAC are two formulations of the same base growth hormone-releasing hormone (GHRH) analog, but they differ dramatically in pharmacokinetics and physiological effect. The no-DAC version has a ~30-minute half-life, requires daily injection, and preserves the natural pulsatile pattern of growth hormone release. The DAC (Drug Affinity Complex) version binds to albumin for an ~8-day half-life, requires only weekly dosing, but produces constant elevated GH levels that override natural pulsatility. Most experienced users and clinics prefer the no-DAC version for its more physiological GH release pattern.

Side-by-side comparison diagram of CJC-1295 (no DAC) and CJC-1295 DAC mechanisms of action
Conceptual comparison — not to scale

Head-to-Head Comparison

CriteriaCJC-1295 (no DAC)CJC-1295 DAC
Primary mechanismGHRH analog — stimulates pulsatile GH release from anterior pituitaryGHRH analog with albumin-binding DAC — sustained GH elevation from anterior pituitary
Half-life~30 minutes~8 days (due to albumin binding via Drug Affinity Complex)
Injection frequency1–3× daily (typically before bed and/or upon waking)1–2× per week
GH release patternPulsatile — mimics natural GH secretion rhythmConstant elevation — overrides natural pulsatile pattern (GH "bleed")
Peak GH amplitudeHigher peak GH pulses (sharp, physiological spikes)Lower but sustained GH levels (elevated baseline without sharp peaks)
IGF-1 elevationModerate sustained IGF-1 increaseHigher sustained IGF-1 increase (due to constant GH stimulation)
Best paired withGHRP (Ipamorelin, GHRP-6, GHRP-2, Hexarelin) for synergistic pulsatile releaseCan be used alone due to long half-life; less commonly paired with GHRPs
Receptor desensitization riskLow — pulsatile stimulation allows receptor recovery between dosesHigher — constant GHRH receptor stimulation may lead to receptor downregulation over time
ConvenienceLower — requires daily injections, often multiple per dayHigher — weekly injection only
Side effectsMild — water retention, tingling, increased hunger (transient around injection)More pronounced — sustained water retention, potential cortisol/prolactin elevation, injection site reactions
Preferred by cliniciansYes — most anti-aging and peptide clinics prefer no-DAC for physiological mimicryLess commonly prescribed — some clinics use for convenience-focused patients
Approximate monthly cost$50–$100/month$60–$120/month

When to Choose Each

Choose CJC-1295 (no DAC)

Physiological GH optimization, pairing with GHRP peptides (Ipamorelin stack), anti-aging protocols, body composition improvement, users who want to mimic natural GH pulsatility

Choose CJC-1295 DAC

Maximum convenience (weekly dosing), patients who cannot inject daily, sustained IGF-1 elevation for recovery, users prioritizing simplicity over optimal GH kinetics

Verdict

CJC-1295 without DAC (MOD-GRF 1-29) is the preferred choice for most users seeking growth hormone optimization. Its short half-life preserves the natural pulsatile GH release pattern that the body is designed for, avoids receptor desensitization, and pairs synergistically with GHRPs like Ipamorelin for amplified GH pulses. CJC-1295 DAC is better suited for users who prioritize convenience and cannot commit to daily injections — but the constant GH elevation it produces is less physiological and may lead to more side effects (sustained water retention, potential receptor downregulation) over time. The standard clinical protocol is CJC-1295 no-DAC + Ipamorelin dosed 1–3 times daily.

References

  1. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone (2006) — PubMed
  2. Modified (Mod) GRF 1-29 and growth hormone secretagogue peptides: clinical applications (2012) — PubMed
  3. Growth hormone-releasing hormone analog enhances GH pulsatility and IGF-I levels in healthy men (2006) — PubMed
  4. Drug Affinity Complex (DAC) technology for half-life extension of peptide therapeutics (2006) — PubMed

Frequently Asked Questions

What is the Drug Affinity Complex (DAC) and how does it work?
The DAC is a chemical modification (specifically a maleimidopropionic acid-lysine linker) that allows CJC-1295 to covalently bind to serum albumin after injection. Albumin is the most abundant protein in blood and has a half-life of ~19 days. By "hitching a ride" on albumin, CJC-1295 DAC extends its own half-life from ~30 minutes to approximately 8 days. This means a single injection continues stimulating GH release for over a week, but it also means you cannot turn it off — it produces continuous GH elevation rather than the sharp pulses the no-DAC version creates.
Why is pulsatile GH release considered better than constant elevation?
Natural GH secretion follows a pulsatile pattern — large spikes during deep sleep, after exercise, and during fasting, with low levels in between. This pattern is important because: (1) GH receptors need recovery time between pulses to remain sensitive and avoid downregulation, (2) the amplitude of GH pulses determines their biological effect on fat metabolism and tissue repair, and (3) constant GH elevation can increase cortisol, prolactin, and insulin resistance. Exogenous HGH injections also create pulses (one large spike), which is why no-DAC CJC-1295 more closely mimics natural and pharmaceutical GH patterns.
What is the best CJC-1295 (no DAC) + Ipamorelin protocol?
The most common clinical protocol is CJC-1295 no-DAC (MOD-GRF 1-29) 100 mcg + Ipamorelin 100–200 mcg injected subcutaneously 1–3 times daily. The most important dose is before bed (to amplify the natural nocturnal GH pulse). A second dose can be taken upon waking on an empty stomach, and a third post-workout. Inject on an empty stomach (no food 2 hours before or 30 minutes after) since insulin and blood sugar blunt GH release. Cycle 5 days on / 2 days off, or use continuously for 3–6 months.
Does CJC-1295 (either version) suppress natural GH production?
Unlike exogenous HGH, CJC-1295 works by stimulating your own pituitary gland to produce and release GH — it does not bypass the pituitary. This means it should not cause the HPA axis suppression seen with direct HGH injections. However, CJC-1295 DAC's constant stimulation may cause some degree of pituitary GHRH receptor desensitization over time (reduced responsiveness), though this is reversible upon cessation. The no-DAC version's pulsatile stimulation largely avoids this issue.
How do I know which version of CJC-1295 I am buying?
Confusion between the two versions is common in the peptide marketplace. Key identifiers include: CJC-1295 without DAC is often labeled as "Mod GRF 1-29" or "Modified GRF 1-29" and has a molecular weight of approximately 3,367 Da. CJC-1295 with DAC has a molecular weight of approximately 3,647 Da due to the added DAC moiety. Reputable suppliers should clearly specify which version they sell and provide a certificate of analysis (COA) with mass spectrometry data confirming the molecular weight. If a vendor does not distinguish between the two or cannot provide testing data, that is a quality concern. Consulting a healthcare provider experienced in peptide therapy can help ensure you obtain the intended formulation.

Explore next