Mod GRF (1-29) — Research Dossier
Evidence grading
Identity
CJC-1295 no-DAC
Also: Modified GHRH(1-29), tetra-substituted
Basis
GHRH(1-29)
Four amino-acid substitutions improving enzymatic stability
DAC present?
No
Short-acting vs multi-day half-life of DAC CJC-1295
Direct human trials
0
Evidence inferred from GHRH/sermorelin and DAC CJC-1295 data
Mod GRF (1-29) is the molecule sold as "CJC-1295 without DAC" — a short-acting GHRH analogue with no direct human clinical trial data, whose expected behaviour is inferred from established GHRH receptor pharmacology and the DAC CJC-1295 trials by subtracting the half-life-extending component.
Mod GRF (1-29) is GHRH(1-29) with four amino-acid substitutions that improve enzymatic stability over native sermorelin/GHRH(1-29), but without the Drug Affinity Complex (DAC) that gives CJC-1295 with DAC its multi-day half-life. It is most widely sold and discussed under the name "CJC-1295 no-DAC" — a naming convention that has generated persistent confusion with the distinct, DAC-bearing compound behind the published clinical trial data.
The absence of DAC means Mod GRF (1-29) is short-acting, producing a brief pulsatile GH signal closer in pharmacokinetic profile to native GHRH and sermorelin than to long-acting CJC-1295. It is commonly discussed alongside a ghrelin-receptor agonist such as ipamorelin on the rationale that simultaneous activation of the two independent GH-release pathways produces a more robust and physiological GH pulse.
“Mod GRF (1-29) is the CJC-1295 no-DAC product — the same tetra-substituted GHRH(1-29) backbone without the albumin-binding Drug Affinity Complex. The Teichman 2006 clinical trial data was generated with the DAC form and cannot be applied to this short-acting molecule.”
— Teichman SL et al., J Clin Endocrinol Metab 2006 (DAC form only)
Naming clarification: DAC vs no-DAC
Two distinct molecules are sold under the "CJC-1295" name:
- CJC-1295 with DAC: GHRH(1-29) with four amino-acid substitutions plus a Drug Affinity Complex (DAC) enabling covalent albumin binding and a multi-day half-life. This is the form studied in the Teichman (2006) trial showing sustained GH/IGF-1 elevation and is the compound behind all published clinical data attributed to "CJC-1295."
- Mod GRF (1-29) = CJC-1295 without DAC: The same tetra-substituted GHRH(1-29) backbone, without the DAC. Short-acting, producing a brief pulsatile GH signal. Marketing this product under the "CJC-1295" name without the DAC qualifier is the source of the persistent naming confusion.
The CJC-1295 dossier in this journal covers the DAC-bearing form and its trial data. This entry exists to make the no-DAC distinction explicit and to prevent researchers from attributing DAC-form evidence to the no-DAC product.
Mechanism
Mod GRF (1-29) binds the GHRH receptor (GHRHR) on pituitary somatotrophs to stimulate pulsatile GH release, subject to somatostatin feedback. Its short half-life means it generates a brief GH pulse, closer in kinetic profile to native GHRH and sermorelin than to long-acting CJC-1295 with DAC.
The four amino-acid substitutions improve resistance to enzymatic degradation over native GHRH(1-29), extending bioavailability modestly relative to unmodified sermorelin without conferring the multi-day residence of the DAC form.
Evidence base
There are no published human clinical trials of Mod GRF (1-29) as a distinct entity. Its expected behaviour is inferred from: (a) the GHRH and sermorelin literature on short-acting GHRH-receptor agonism and (b) the DAC CJC-1295 trial data, from which the no-DAC pharmacology is extrapolated by removing the half-life-extending component. The direct evidence base is preclinical and mechanistic.
Researchers attributing the Teichman (2006) sustained-GH data to the no-DAC product are applying evidence that does not belong to this molecule. This is the most important point to communicate when evaluating marketing claims for Mod GRF (1-29) products.
Regulatory status
No approval from any major regulator. As a GH secretagogue and GHRH analogue, it falls under WADA category S2 (peptide hormones, growth factors, and related substances — prohibited in competition and out-of-competition). Material supplied for laboratory work is research-use-only in the UK.
References
- 1
Teichman SL, et al. Prolonged stimulation of growth hormone and IGF-I secretion by CJC-1295, a long-acting analog of GHRH, in healthy adults J Clin Endocrinol Metab 2006.
- 2
Prakash A, Goa KL. Sermorelin — a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency BioDrugs 1999.
Research & Laboratory Use Only
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