CJC-1295 DAC Dosing Guide: Weekly GH (2026)

CJC-1295 DAC (Drug Affinity Complex) is a long-acting synthetic GHRH analog that covalently binds to serum albumin after injection, extending its half-life from minutes to approximately 8 days. This makes it the only GHRH analog that can be dosed weekly while maintaining sustained GH and IGF-1 elevation.

The only GHRH analog with human clinical trial data: CJC-1295 DAC has been studied in multiple clinical trials demonstrating dose-dependent, prolonged increases in GH and IGF-1. Community dosing is informed by this data, though no trials have been conducted for the anti-aging and body composition goals typical of community use. This is not medical advice.

Quick Reference: Community Dosing

Key advantage: Weekly or twice-weekly dosing vs. 2–3 daily injections required for the no-DAC version. Significantly better adherence and convenience.

For the full CJC-1295 DAC peptide profile, vendor pricing, and comparisons, see our CJC-1295 DAC peptide page.

Loading vs Maintenance

CJC-1295 DAC has unique pharmacokinetics due to albumin binding that affect dosing strategy:

Initial period (Weeks 1–2): Start at 1–2 mg twice weekly. Due to the ~8-day half-life, steady-state levels are reached after approximately 2–3 injections (10–14 days). IGF-1 begins rising within 2–3 days of first injection.

Steady state (Weeks 3+): Continue at established dose. IGF-1 levels stabilize at elevated levels. Blood work at week 4 is recommended to verify IGF-1 is in the target range (upper-normal, not supraphysiological).

Dose adjustment: If IGF-1 is too high (>350 ng/mL), reduce to once weekly or lower dose. If response is insufficient, consider increasing to 2 mg twice weekly or adding a GHRP.

Timing Considerations

• Injection day flexibility: Unlike no-DAC, timing within the day is less critical due to long half-life
• Evening injection preferred by many to align with nocturnal GH physiology
• Fasting less critical than no-DAC — the sustained release pattern means acute insulin spikes have less impact
• Consistent schedule: Pick 2 days per week (e.g., Monday/Thursday) and maintain consistency

Routes of Administration

Subcutaneous Injection (Standard)

The only route used in both clinical trials and community protocols:

• Injection sites: Abdomen, love handles, thighs, deltoid area
• Volume: Typically 0.2–0.5 mL depending on concentration
• Needle: 29–31 gauge insulin syringe
• Depth: Standard subcutaneous (pinch skin, 45–90° angle)

Reconstitution

For standard 2 mg vials:

• 2 mg vial + 1 mL bacteriostatic water = 2,000 mcg/mL (2 mg/mL)
• 2 mg dose = 1 mL (full vial per injection)
• 1 mg dose = 0.5 mL = 50 units

For 5 mg vials:

• 5 mg vial + 2.5 mL bacteriostatic water = 2,000 mcg/mL
• 2 mg dose = 1 mL = 100 units
• Swirl gently, refrigerate at 2–8°C, use within 28 days

DAC Binding Mechanism

After subcutaneous injection, the DAC moiety (a reactive GRF analog) forms a covalent bond with serum albumin via a maleimide-thiol reaction. This albumin conjugation:

• Extends half-life to ~8 days (vs ~30 min for no-DAC)
• Provides sustained GHRH receptor stimulation
• Creates a depot-like pharmacokinetic profile

Where These Numbers Come From: Clinical Context

CJC-1295 DAC is unique among GH secretagogues in having direct human clinical trial data.

Pivotal Pharmacokinetic/Pharmacodynamic Study

Teichman et al. conducted the first human study of CJC-1295 DAC in 36 healthy adults (21–61 years). Key findings:

• Single doses of 30, 60, or 120 mcg/kg produced dose-dependent GH and IGF-1 increases
• IGF-1 increased 1.5–3 fold above baseline
• IGF-1 remained elevated for 6–14 days after a single injection
• GH levels increased 2–10 fold with sustained pulsatile pattern
• Mean half-life estimated at 5.8–8.1 days

(Teichman et al., 2006)

Preserved Pulsatility Study

A critical follow-up demonstrated that despite continuous GHRH receptor stimulation from the long half-life, pulsatile GH secretion was maintained:

• GH pulse frequency preserved (no continuous flat elevation)
• Mean GH concentration increased 2-fold
• GH pulse mass (amount per pulse) doubled
• Somatostatin-mediated GH troughs remained intact

This allayed concerns that sustained GHRH stimulation might cause non-physiological continuous GH secretion (Ionescu & Bhatt, 2006).

Animal Growth Normalization

CJC-1295 normalized growth in GHRH knockout mice with once-daily administration, demonstrating its ability to fully replace endogenous GHRH function. The same dose was less effective at 48 or 72-hour intervals (Alba et al., 2006).

Community Protocol Development

Community doses (1–4 mg twice weekly) are derived from:

1. Clinical trial dose ranges (30–120 mcg/kg single dose)
2. Target of upper-normal IGF-1 rather than supraphysiological
3. Twice-weekly dosing to maintain more stable levels than once-weekly
4. Empirical IGF-1 blood work confirmation

Mechanism of Action

CJC-1295 DAC combines a modified GHRH (1-29) peptide with a Drug Affinity Complex that enables albumin binding:

GHRH receptor activation — The GRF (1-29) portion binds to GHRHR on pituitary somatotropes, activating Gαs-cAMP-PKA signaling to promote GH synthesis and release. The four amino acid substitutions (same as no-DAC) improve metabolic stability.

Albumin conjugation (DAC) — The maleimide-based DAC moiety reacts with a free cysteine on albumin (Cys-34), forming an irreversible thioether bond. This protects the peptide from enzymatic degradation and renal clearance, extending half-life from ~30 minutes to ~8 days.

Sustained GHRH tone — Unlike pulsatile no-DAC, CJC-1295 DAC provides continuous GHRH receptor occupancy. However, natural somatostatin cycling still modulates GH release into pulses, resulting in an elevated-but-pulsatile GH pattern.

GH/IGF-1 axis stimulation — Chronic GH elevation stimulates hepatic IGF-1 production. The sustained nature of DAC stimulation produces more consistent IGF-1 elevation compared to the peaks-and-troughs of no-DAC or pulsatile GHRPs.

Negative feedback preservation — Unlike exogenous GH injection (which suppresses endogenous GH production), CJC-1295 DAC stimulates the body's own somatotropes. GH production remains responsive to natural regulatory mechanisms including somatostatin and IGF-1 feedback.

Side Effects & Safety

CJC-1295 DAC has clinical trial safety data, making its side effect profile better characterized than most secretagogues.

Side Effects from Clinical Trials

• Injection site reactions — Most common adverse event (mild erythema, pain)
• Flushing/warmth — Transient, typically 15–30 minutes post-injection
• Headache — Mild, reported in some subjects
• Diarrhea — Occasional, usually transient
• No serious adverse events reported in published clinical trials

Community-Reported Side Effects

• Water retention — More pronounced than no-DAC due to sustained GH elevation
• Numbness/tingling in extremities — Carpal tunnel-like symptoms at higher doses
• Joint stiffness — Related to GH-mediated fluid retention
• Increased appetite — Moderate, less than GHRP-6 or MK-677
• Vivid dreams — Common, generally pleasant

GH-Related Concerns (Chronic Use)

• Insulin resistance — Monitor fasting glucose; sustained GH elevation can impair glucose tolerance
• IGF-1 elevation — Epidemiological association with certain cancers at supraphysiological levels
• Fluid retention — May worsen blood pressure in susceptible individuals
• Acromegaly symptoms — Theoretical at very high doses (joint enlargement, facial changes)

Monitoring Recommendations

Contraindications

• Active malignancy
• Diabetic retinopathy
• Active acromegaly
• Pregnancy and lactation
• Known hypersensitivity to GHRH analogs

Stacking CJC-1295 DAC

CJC-1295 DAC can be used standalone or combined with other agents.

CJC-1295 DAC + Ipamorelin (Bedtime Pulses)

Some users add bedtime GHRP pulses on top of sustained DAC stimulation:

• CJC-1295 DAC → continuous GHRH tone, sustained IGF-1 elevation
• Ipamorelin → acute GH pulse amplification at bedtime

CJC-1295 DAC Standalone (Simplicity Protocol)

Many users prefer DAC alone for its convenience:

• 2 mg twice weekly — no daily injections needed
• Consistent IGF-1 elevation without daily timing requirements
• Simpler protocol with fewer variables

CJC-1295 DAC vs MK-677

Common comparison — both provide sustained GH elevation:

Stacking Considerations

• Avoid combining with other GHRH analogs (sermorelin, no-DAC CJC) — redundant receptor activation
• GHRP addition is optional — DAC provides sufficient baseline stimulation alone
• Monitor IGF-1 carefully when stacking — easy to overshoot into supraphysiological range
• Do not combine with exogenous GH — overlapping mechanisms with added suppression risk

Frequently Asked Questions

What is the standard CJC-1295 DAC dose?

2 mg subcutaneous twice weekly is the most common community protocol. Clinical trials used 30–120 mcg/kg single doses (roughly 2–8 mg). Start at 1–2 mg twice weekly and adjust based on IGF-1 blood work.

How often do I inject CJC-1295 DAC?

Once or twice weekly. The ~8-day half-life from albumin binding allows for infrequent dosing. Twice weekly provides more stable levels; once weekly is simpler but has more fluctuation. Pick consistent days (e.g., Monday/Thursday).

Does CJC-1295 DAC produce natural GH pulses?

Yes — clinical studies confirmed pulsatile GH secretion is preserved despite continuous GHRH receptor stimulation. Somatostatin still modulates GH release into pulses, though baseline GH between pulses is higher than with the no-DAC version.

CJC-1295 DAC vs no DAC — which should I choose?

DAC: convenient weekly dosing, sustained IGF-1, less timing-dependent, better for compliance. No-DAC: more physiological pulsatile pattern, requires 2–3 daily injections, better GHRP synergy, more controllable. Choose based on lifestyle and protocol preferences.

How long until I see results?

IGF-1 rises within 2–3 days and stabilizes by week 2. Sleep quality improvements are often noticed first (1–2 weeks). Body composition changes (fat loss, recovery) typically appear at 4–8 weeks. Full effects develop over 3–6 months.

Is CJC-1295 DAC better than MK-677?

Different profiles. DAC has a cleaner side effect profile with less hunger and insulin resistance risk, but requires injection. MK-677 is oral and cheaper but causes significant hunger and greater insulin resistance. Many consider DAC superior for body composition goals.

Related Guides

• CJC-1295 No DAC Dosing Guide — Short-acting version for pulsatile protocols
• CJC-1295 + Ipamorelin Dosing Guide — Combined stack protocol guide
• Ipamorelin Dosing Guide — GHRP for pulse amplification
• MK-677 Dosing Guide — Oral GH secretagogue comparison
• Sermorelin Dosing Guide — Alternative GHRH analog

References

For educational and research purposes only. This is not medical advice. CJC-1295 DAC has human clinical data for GH/IGF-1 stimulation but has not been approved for anti-aging or body composition use. Consult a healthcare provider before use.