CJC-1295 Research: GH and IGF-1 Data from the Human Dose-Escalation Trials
A study-by-study look at CJC-1295 — the drug-affinity-complex technology behind its long half-life, and the human trials that measured its effect on GH pulsatility and IGF-1.
Mechanism of action
CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH), based on the first 29 amino acids of the native hormone — the shortest fragment retaining full biological activity.
Four amino-acid substitutions protect the peptide from dipeptidyl peptidase-4 (DPP-4) degradation, which destroys native GHRH within minutes.
The DAC (drug affinity complex) version adds a maleimidoproprionic acid linker that forms a covalent bond with circulating albumin, extending the half-life from minutes to roughly one to two weeks. The no-DAC version — functionally modified GRF (1-29) — lacks this linker and clears within about 30 minutes.
Because CJC-1295 acts on the pituitary GHRH receptor rather than supplying growth hormone directly, GH release remains subject to somatostatin feedback and retains a pulsatile pattern rather than producing a flat elevated level.
The studies
CJC-1295's human data comes chiefly from two early-phase trials published in the Journal of Clinical Endocrinology & Metabolism. The distinction between DAC and no-DAC versions matters for interpreting all of it.
Teichman et al. — single-dose escalation of CJC-1295 in healthy adults
To assess the safety, pharmacokinetics and effect on GH and IGF-1 of ascending single subcutaneous doses of CJC-1295 (DAC) in healthy adults.
Healthy adult volunteers · randomised, double-blind, placebo-controlled ascending single dose
- 2 - 10-fold
- Mean GH increase
- 1.5 - 3-fold
- Mean IGF-1 increase
- ~5.8-8.1 days
- Half-life
sustained for 6 days
sustained 9-11 days
- This trial established that albumin-binding DAC technology can hold GHRH-analogue activity in circulation for over a week from a single injection.
- GH secretion remained pulsatile — the analogue amplified natural pulses rather than replacing them with a flat elevation.
- No serious adverse events were reported at the doses tested; injection-site reactions were the most common finding.
Multiple-dose administration and IGF-1 maintenance
To determine whether repeated weekly or biweekly dosing of CJC-1295 sustains elevated IGF-1 without desensitising the pituitary GHRH receptor.
Healthy adults · repeated subcutaneous dosing over multiple weeks · serial GH and IGF-1 sampling
- Sustained
- IGF-1 elevation
- Not observed
- Pituitary desensitisation
- Preserved
- GH pulse pattern
across repeated dosing
at the doses studied
- Repeated dosing did not blunt the response, which is the central pharmacological question for any GHRH analogue.
- Sustained IGF-1 elevation without loss of pulsatility is the property that distinguishes GHRH analogues from exogenous GH administration.
- Long-term safety beyond these short trials has not been characterised in published human data.
DAC versus no-DAC: interpreting the two forms
To clarify how the drug-affinity-complex version differs pharmacologically from the no-DAC form widely sold as modified GRF (1-29).
Comparative pharmacokinetic characterisation of the two constructs
- ~6-8 days
- DAC half-life
- ~30 minutes
- No-DAC half-life
- Bleed vs pulse
- GH profile
sustained elevation vs discrete pulse
- Most published human trial data concerns the DAC version. Literature on the no-DAC form is largely extrapolated from GRF (1-29) research.
- The no-DAC form produces a short, discrete GH pulse, which is why it is typically studied alongside a GH secretagogue such as ipamorelin.
- When citing CJC-1295 data, always state which construct the source studied — the two are not interchangeable.
Storage & handling
CJC-1295 research material is supplied as a lyophilised powder. Store sealed vials frozen or refrigerated, protected from light and moisture.
Reconstitute with bacteriostatic water added slowly down the inner wall of the vial; swirl gently until dissolved — never shake, as GHRH analogues are sensitive to mechanical denaturation.
Keep reconstituted solution at 2-8 °C and use within your lab's defined stability window. Avoid repeated freeze-thaw cycles.
All information on this page is provided for laboratory and educational reference only. Peptides Lab SA (PTY) Ltd supplies compounds strictly for in-vitro research use. Nothing here is medical advice, a dosing recommendation, or a claim of human safety or efficacy.