CJC-1295 DAC
A long-acting GHRH analog whose Drug Affinity Complex binds albumin to stretch its half-life to roughly a week, producing sustained GH and IGF-1 elevation from a single weekly injection.
CJC-1295 DAC is a synthetic 30-amino-acid growth hormone-releasing hormone (GHRH) analog carrying a Drug Affinity Complex (DAC) — a maleimidopropionic acid group that forms a covalent bond with the cysteine-34 residue on circulating serum albumin. This albumin conjugation extends the plasma half-life from the minutes of native GHRH or Mod GRF 1-29 to approximately 6-8 days, turning the peptide into a long-circulating depot that continuously stimulates pituitary GHRH receptors. Rather than the sharp, physiologic GH pulses of the non-DAC form, DAC produces a sustained GH/IGF-1 plateau, which is its defining advantage (weekly dosing) and its central trade-off (non-pulsatile physiology). It has no FDA approval; clinical development was discontinued at Phase 2, and it is sold research-only.
Class
Synthetic long-acting GHRH analog (albumin-binding peptide conjugate)
Half-life
6-8 days (approximately 8 days effective, due to covalent binding to serum albumin)
Routes
Subcutaneous
Category
Growth Hormone & Performance
Researched benefits
What it's studied for
Sustained GH and IGF-1 elevation
In the Teichman Phase 1 trial a single subcutaneous dose raised mean GH 2-10 fold above baseline for 6-14 days, with IGF-1 rising 1.5-3 fold and remaining elevated for up to 28 days on repeated weekly dosing. The albumin-bound depot continuously exposes pituitary GHRH receptors to ligand rather than delivering discrete pulses.
Once-weekly dosing convenience
The ~8-day half-life allows a single weekly (1-2 mg) subcutaneous injection instead of the 2-3 times-daily schedule required by short-acting Mod GRF 1-29. This convenience is DAC's headline advantage over the non-DAC form.
Endogenous GH stimulation
As a secretagogue it stimulates the body's own pituitary GH output rather than supplying exogenous growth hormone, preserving a degree of physiologic feedback compared with recombinant hGH administration.
Body-composition support
Sustained IGF-1 elevation is studied in the context of modest lean-mass gain and fat loss over 8-12 week cycles; realistic changes are described as a few percent improvement in lean mass and body fat with training and nutrition, benchmarked against the more robust results of recombinant hGH.
Recovery and connective-tissue context
The elevated IGF-1 window is used in research and community protocols to support recovery from training and injury, and DAC is sometimes paired with recovery peptides during this window.
Mechanism
How it works
CJC-1295 DAC shares the same pharmacodynamic mechanism as the non-DAC variant — agonism at the GHRH receptor on pituitary somatotrophs — but has radically different pharmacokinetics. The peptide is the modified GHRH(1-29) sequence carrying four stabilizing amino-acid substitutions, with an added maleimidopropionic acid (MPA) reactive group at the C-terminus. The MPA moiety is highly reactive toward free thiol groups, and serum albumin carries one free cysteine (Cys-34) per molecule; within hours of subcutaneous injection the peptide forms a covalent thioether bond with albumin Cys-34, converting the small peptide into a long-circulating albumin-peptide conjugate.
This albumin conjugation is the defining feature of the DAC form. The conjugate circulates for much of albumin's ~20-day half-life, giving CJC-1295 DAC an effective drug half-life of approximately 8 days — versus roughly 30 minutes for Mod GRF 1-29 and under 2 minutes for native GHRH. Because the albumin-bound conjugate slowly releases GHRH-receptor-active peptide over days, the pituitary is continuously exposed to ligand. This eliminates the normal somatostatin-driven 'off' periods between pulses and produces a GH/IGF-1 plateau rather than discrete peaks, at the cost of blunting natural nocturnal pulsatility and potentially inducing partial receptor desensitization with chronic dosing.
Downstream, sustained GH elevation drives hepatic JAK2/STAT5 signaling and continuous IGF-1 mRNA transcription. IGFBP-3 rises proportionally (it binds roughly 90% of circulating IGF-1), free bioactive IGF-1 rises modestly, and tissue IGF-1 in muscle, bone and cartilage rises more substantially. Unlike ghrelin-receptor agonists such as the GHRPs and ipamorelin, DAC has no direct activity at GHS-R1a; any pulsatile component from a stacked GHRP must be dosed separately because of the timing mismatch between weekly DAC and daily secretagogues.
The practical contrast with Mod GRF 1-29 (without DAC) frames how the two are used: DAC gives a ~8-day half-life, a continuous GH plateau, weekly dosing, higher IGF-1 magnitude (1.5-3x) and higher desensitization risk, whereas the non-DAC form gives a ~30-minute half-life, pulsatile peaks, 2-3x daily dosing, greater physiologic mimicry and strong synergy with ipamorelin. This is why many modern protocols favor the non-DAC form despite its inconvenience.
Dosing protocols
Dosing & administration
Dosing reflects protocols reported in research and community literature for educational purposes. It is not medical advice or a recommendation. Most peptides here are not approved for human use.
Reconstitution
Supplied as lyophilized powder, typically 2 mg or 5 mg per vial. Standard reconstitution: 2 mg vial + 2 mL bacteriostatic water (0.9% benzyl alcohol) yields 1 mg/mL (1000 mcg/mL), so a 1 mg dose is 100 units (1.0 mL) on a U-100 insulin syringe. Alternative: 2 mg vial + 1 mL BAC yields 2 mg/mL, so 1 mg is 50 units (0.5 mL) and 2 mg is 100 units (1.0 mL). Inject BAC slowly down the inner glass wall, swirl gently (never shake), allow ~5 min to dissolve, then label and refrigerate. The maleimide (MPA) group is sensitive to heat (hydrolysis), freezing of reconstituted solution (aggregation) and UV light (photodegradation) — keep the vial refrigerated, upright and out of light.
Beginner
- Dose
- 0.5-1 mg (1000 mcg typical, 500 mcg for side-effect management)
- Frequency
- Once weekly
- Timing
- Same day each week, evening/pre-bed conventional (timing not critical due to sustained release)
- Duration
- 8-12 week entry cycle
- Route
- Subcutaneous (lower abdomen, thigh or upper arm; rotate sites)
Establish tolerance and calibrate IGF-1 response with no other GH-axis agents. Requires baseline IGF-1, IGFBP-3, fasting glucose and HbA1c plus up-to-date cancer screening. Check IGF-1 at week 4; reduce to 0.5 mg if IGF-1 too high or side effects appear. Many clinicians recommend trying Mod GRF 1-29 + ipamorelin before ever starting DAC.
Intermediate
- Dose
- 1-2 mg
- Frequency
- Once weekly
- Timing
- Same day each week
- Duration
- 12 weeks on, 4 weeks off (quarterly); annual 4-6 week break minimum
- Route
- Subcutaneous with site rotation
Continues beyond a completed introductory cycle in tolerant responders. Target IGF-1 at the 70-80th percentile for age, not higher. Reduce dose 25% if IGF-1 exceeds age-specific upper limit; increase to 2 mg only if mid-normal with no benefit. Monitor IGF-1, fasting glucose and HbA1c quarterly.
Advanced
- Dose
- 1-2 mg (2 mg is the ceiling; do not exceed)
- Frequency
- Once weekly, or split twice weekly (e.g. Mon + Thu)
- Timing
- Same day(s) each week
- Duration
- 12 weeks on / 4 weeks off, with an annual month-long break; long-term continuous use without breaks not recommended
- Route
- Subcutaneous with site rotation
For users with a 12+ month characterized response. Do not escalate above 2 mg (diminishing returns, rising side effects), do not chase higher IGF-1, and do not stack with Mod GRF 1-29, IGF-1 LR3 or MGF. Comprehensive quarterly labs (IGF-1, IGFBP-3, fasting glucose, insulin, HbA1c, HOMA-IR, lipids, hs-CRP, CBC, CMP) plus annual DEXA and age-appropriate cancer screening.
- Weight-based reference: approximately 20-30 mcg/kg per week, with a standard flat dose of 1-2 mg/week for most individuals. Note that the 30-90 mcg/kg doses in the Teichman Phase 1 trial (about 2-6 mg for a 70 kg adult) are far higher than modern 1-2 mg community doses, which achieve similar IGF-1 plateaus with fewer side effects because the dose-response flattens after ~2 mg.
- Unlike Mod GRF 1-29, injection does not strictly require a fasted state — the sustained release largely overrides postprandial somatostatin blunting — though some users prefer a pre-bed dose 2+ hours after dinner.
- Because of the ~8-day half-life there is 2-3 days of grace built in; a dose missed by under 48 hours can be taken and the schedule continued, but do not double-up if more than 48 hours late.
- DAC cannot be rapidly reversed: full washout takes 3-4 weeks and IGF-1 returns to baseline over 4-6 weeks, so side effects resolve slowly and elective major surgery requires holding the peptide 2-3 weeks ahead.
- Switching forms requires a washout: allow 3-4 weeks after the last DAC dose before starting Mod GRF 1-29; the non-DAC form clears fast enough to start DAC within 48 hours of stopping it. Never run both simultaneously — they target the same receptor and stacking is redundant.
- Reconstituted solution is stable refrigerated (2-8°C) for up to 28 days; store lyophilized powder at -20°C, protect from light, and never freeze the reconstituted solution.
Evidence
Research & clinical studies (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, in healthy adults
A Phase 1 randomized dose-escalation trial in healthy adults found single subcutaneous doses of CJC-1295 produced dose-dependent, sustained increases in mean GH (2-10x baseline for 6-14 days) and IGF-1 (1.5-3x baseline for up to 28 days with repeated weekly dosing).
PMID 16352683Combinations
Stacking & blends
DAC + Ipamorelin (pulse + sustain)
Add a pulsatile GH component on top of the sustained DAC baseline
Ipamorelin is a GHS-R1a agonist acting on a complementary pathway; because DAC provides no ghrelin-receptor activity, ipamorelin is dosed daily while DAC is dosed weekly. This pairing is controversial — DAC already approaches pituitary capacity, so some clinicians consider added daily ipamorelin redundant or a desensitization risk, and it is best skipped if DAC alone produces adequate IGF-1 or if DAC side effects are present.
DAC + Connective-tissue recovery
Support recovery and connective tissue during the elevated IGF-1 window
BPC-157 (about 250 mcg twice daily) and TB-500 (about 2 mg weekly) are used alongside DAC for tendon, gut and connective-tissue support with no receptor conflict, leveraging the sustained IGF-1 environment for tissue repair.
DAC longevity/body-composition stack
Broader recovery and longevity support during a DAC cycle
Advanced protocols surround weekly DAC with NAD+ precursors, creatine, vitamin D3/K2/magnesium and omega-3, plus clinician-supervised testosterone if indicated, while avoiding simultaneous Mod GRF 1-29 and other IGF-axis peptides (IGF-1 LR3, MGF).
Safety
Side effects & considerations
Commonly reported effects
Contraindications & cautions
- Active malignancy of any type
- History of cancer within 5 years (relative; discuss with oncologist)
- Active or prior diabetic retinopathy
- Pregnancy and lactation
- Children with open growth plates
- Critical illness requiring ICU care
- Severe uncontrolled type 2 diabetes (HbA1c >8); controlled type 2 diabetes is a relative contraindication
- Active acromegaly or pituitary adenoma / tumor
- Obstructive sleep apnea, severe hypothyroidism, intracranial pathology and family history of acromegaly (relative)
Adverse effects mirror the non-DAC variant but are more sustained because GH elevation is continuous rather than pulsatile — edema, carpal-tunnel symptoms and glucose intolerance are more common and more severe, and receptor desensitization risk is higher. The chief theoretical long-term concern is sustained elevated IGF-1 as a pro-tumorigenic signal. Manage side effects with 25% dose reductions; stop for rising fasting glucose (>105 mg/dL) or HbA1c, new diabetic retinopathy, any malignancy workup, or acromegaly-like features. Key drug interactions: somatostatin analogs (direct GH suppression, incompatible), glucocorticoids and high-dose oral estrogens (blunt response), insulin/secretagogues (monitor glucose), and chemotherapy agents (avoid). Because of the ~8-day half-life the compound cannot be rapidly discontinued — plan a 3-4 week washout for surgery or side-effect resolution.
FAQ
CJC-1295 DAC — common questions
What makes DAC different from regular CJC-1295?
The DAC (Drug Affinity Complex) is a maleimidopropionic acid group at the C-terminus that, once injected, forms a covalent bond with cysteine-34 on serum albumin, turning the small peptide into a long-circulating albumin-peptide conjugate. This extends the half-life from ~30 minutes (non-DAC) to ~8 days, allowing weekly instead of multiple-times-daily dosing. The trade-off is that DAC produces continuous, non-pulsatile GH elevation rather than the sharp, physiologic pulses of the non-DAC form.
Why do most clinicians prefer the non-DAC version now?
Three reasons: the non-DAC form (Mod GRF 1-29) preserves the body's natural pulsatile GH release, which is considered safer and more physiologic; Mod GRF 1-29 stacks with ipamorelin for a synergistic GH pulse that DAC cannot match due to timing mismatch; and side effects such as edema, carpal tunnel and glucose intolerance are more common and severe with DAC's sustained elevation. Weekly convenience is DAC's headline advantage, but for most users it does not outweigh the physiologic trade-offs.
How long does DAC stay in my system after I stop?
The half-life is about 8 days, so full washout takes 3-4 weeks and IGF-1 gradually returns to baseline over 4-6 weeks after the last dose. This long tail means side effects resolve slowly, surgery requires stopping 2-3 weeks ahead, and switching to Mod GRF 1-29 requires waiting for full washout first.
Do I need to inject on an empty stomach like with the non-DAC form?
Not strictly. DAC's sustained-release profile largely overrides postprandial somatostatin blunting, so you can inject with or without food. The fasted-state rule is mandatory for Mod GRF 1-29 but only a preference for DAC; many users inject pre-bed a couple of hours after dinner for convenience and sleep alignment.
Can I stack DAC with ipamorelin?
Opinions vary. The rationale (a synergistic GH pulse from dual-pathway activation) is the same as for non-DAC plus ipamorelin, but because DAC already produces sustained GH elevation, adding daily ipamorelin may push pituitary capacity to its limit without proportional benefit and could compound desensitization. A reasonable approach is to add ipamorelin only if DAC alone gives mid-range IGF-1 with modest benefit, and to avoid it if DAC-related side effects are present.
How much body-composition change can I expect?
Modest, not dramatic. Benchmarked against recombinant hGH in healthy older adults, realistic expectations are roughly a few percent improvement in lean mass and body fat over 3-6 months with consistent training and nutrition. As a secretagogue dependent on pituitary response, DAC produces somewhat less robust changes than direct GH administration — it optimizes baseline physiology, but the training and diet still do the heavy lifting.
Why was clinical development discontinued?
The original developer, ConjuChem Biotechnologies, halted development at Phase 2 in 2007, associated with unexpected fatalities in a separate ConjuChem clinical program that were not directly attributed to CJC-1295. No sponsor has resumed development. Tesamorelin, a shorter-acting GHRH analog, became the FDA-approved GHRH analog instead.
How do I know a vendor is selling the actual DAC variant?
Mass spectrometry is essential because CJC-1295 with DAC has a substantially higher molecular weight (~3,648 Da) than CJC-1295 without DAC (~3,368 Da). HPLC purity testing alone does not distinguish the two, and some vendors mislabel the cheaper non-DAC variant as the DAC version — insist on a certificate of analysis confirming identity by mass spec.
