Mod GRF 1-29 (CJC-1295 no-DAC)

29-amino-acid modified analog of growth hormone-releasing hormone, functionally similar to the approved peptide sermorelin.

Overview

Mod GRF 1-29 is a synthetic 29-amino-acid, C-terminally amidated analog of human growth hormone-releasing hormone (GHRH). It corresponds to the active fragment of GHRH(1-44) with stabilizing modifications, and it is the same peptide backbone used in the long-acting agent CJC-1295 but without the Drug Affinity Complex (DAC) that confers albumin binding. Functionally it is close to sermorelin, the GHRH(1-29) peptide that was approved for diagnostic use, and it acts as a short-acting GHRH-class secretagogue.

Mechanism

Mod GRF 1-29 binds the GHRH receptor on pituitary somatotrophs and stimulates growth hormone synthesis and release. Unlike ghrelin-receptor secretagogues (GHRP class), it does not directly promote hunger signaling. In research protocols it is typically combined with a GHRP-class peptide such as ipamorelin or GHRP-2, whose synergistic pathway produces a larger GH pulse than either alone.

Dosing

In research settings Mod GRF 1-29 is given by subcutaneous injection, commonly one to three times daily in protocols paired with a GHRP-class peptide. Dosing is protocol-specific and should be sourced from the primary literature; the approved peptide sermorelin has its own labeling for diagnostic use.

Expected Effects

rapid, transient release of growth hormone after administration
elevated IGF-1 with repeated dosing in research protocols
amplified GH pulses when combined with ghrelin-receptor secretagogues

Side Effects & Tolerability

As a GHRH-class peptide, reported effects include flushing, injection-site reactions, and transient changes in GH-related parameters. The short-acting format avoids the prolonged receptor exposure of DAC-conjugated versions, but systematic long-term safety data for unapproved use are lacking.

Storage

Lyophilized Mod GRF 1-29 should be stored desiccated, protected from light, and kept frozen at -20 deg C or below. After reconstitution, solutions should be refrigerated at 2-8 deg C and used promptly, without repeated freeze-thaw cycles.