MOD GRF 1 29.

MOD GRF 1 29 is a research compound in the growth-hormone secretagogues.

Stimulating the pituitary's GHRH receptor to release growth hormone.

It draws interest for growth-hormone secretagogues.

F-tier evidence: human evidence is limited; most support is preclinical.

What it is

Mod GRF 1-29 (commonly sold as "CJC-1295 without DAC") is a synthetic 29-amino-acid analog of growth hormone-releasing hormone (GHRH). It is the same tetra-substituted GHRH(1-29) peptide backbone used in CJC-1295, but it lacks the maleimido "Drug Affinity Complex" (DAC) linker that the long-acting form carries, so it behaves as a short-acting GHRH secretagogue. Its parent fragment, native GHRH(1-29) ("sermorelin"), retains essentially the full GH-releasing activity of the 44-residue hormone, and the four engineered substitutions are added to slow enzymatic breakdown.

How it works

Like endogenous GHRH, the peptide binds the GHRH receptor on anterior-pituitary somatotrophs, raising intracellular cAMP and triggering pulsatile synthesis and release of growth hormone, which in turn drives hepatic IGF-1 production. The four amino-acid substitutions relative to native GHRH(1-29)—typically described as D-Ala at position 2, Gln8, Ala15, and Leu27—are intended to resist degradation, with the D-alanine substitution at position 2 specifically blocking cleavage by dipeptidyl peptidase-IV (DPP-IV), the main enzyme that rapidly inactivates GHRH. Because it has no albumin-binding DAC tether, it is cleared quickly and is described as producing brief, pulse-like GH stimulation rather than the sustained "GH bleed" seen with the DAC version. It is mechanistically a secretagogue—it prompts the pituitary's own GH, rather than supplying GH directly.

What the evidence shows

The well-known human trials in this family—Teichman et al. (JCEM, 2006), Ionescu & Frohman (JCEM, 2006), and Sackmann-Sala et al. (Growth Horm IGF Res, 2009)—all studied CJC-1295 WITH DAC, the long-acting albumin-binding version, not the no-DAC Mod GRF 1-29; Alba et al. (2006) used a GHRH-knockout mouse model. There is no robust, peer-reviewed human clinical trial of Mod GRF 1-29 (the no-DAC peptide) under that name establishing efficacy or safety, so claims about it are largely inferred from GHRH/sermorelin pharmacology and from the DAC-form data rather than directly tested. The unmodified parent peptide, sermorelin/GHRH(1-29), was an FDA-approved diagnostic and pediatric GH agent and is the best-characterized human reference point. Most published mentions of the no-DAC compound itself come from anti-doping analytical chemistry (e.g., Henninge et al., Drug Test Anal, 2010, identifying CJC-1295 in an illicit preparation), which characterize the molecule but not its clinical effects. Honest bottom line: the human-versus-preclinical gap is wide here—the short-acting form is plausible by analogy but essentially unproven in controlled human studies.

Safety considerations

Documented safety data specific to Mod GRF 1-29 are minimal because controlled human trials of the no-DAC peptide are lacking; what is known is extrapolated from GHRH analogs broadly. In studies of related GHRH analogs and sermorelin, injection-site reactions (redness, swelling), flushing, and headache are the most commonly reported effects, and any sustained elevation of the GH/IGF-1 axis carries theoretical concerns including fluid retention, joint discomfort, insulin resistance/altered glucose handling, and—because IGF-1 is mitogenic—uncertainty about long-term proliferative risk. A major real-world hazard is that material sold under this name is research-grade and unregulated, so purity, identity, sterility, and contamination are not assured; anti-doping case reports document the compound appearing in mislabeled or "unknown" pharmaceutical preparations. Interactions with somatostatin tone, other secretagogues, and underlying endocrine or oncologic conditions are not well characterized, and long-term human safety is simply unknown.

Regulatory status

Mod GRF 1-29 / CJC-1295 without DAC is not approved by the FDA or any major regulator for any indication and is an investigational/research-use-only compound; its unmodified parent, sermorelin, was previously FDA-approved but has been commercially discontinued. As a GHRH analog it falls under the World Anti-Doping Agency (WADA) Prohibited List class S2 (peptide hormones / growth factors and related substances) and is banned in sport at all times.

1. [1]Prolonged stimulation of GH and IGF-I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults (note: studied the DAC form) — J Clin Endocrinol Metab, 2006; Teichman SL et al.; PMID 16352683
2. [2]Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog — J Clin Endocrinol Metab, 2006; Ionescu M, Frohman LA; PMID 17018654
3. [3]Identification of CJC-1295, a growth-hormone-releasing peptide, in an unknown pharmaceutical preparation — Drug Test Anal, 2010; Henninge J et al.; PMID 21204297
4. [4]Activation of the GH/IGF-1 axis by CJC-1295, a long-acting GHRH analog, results in serum protein profile changes in normal adult subjects — Growth Horm IGF Res, 2009; Sackmann-Sala L et al.; PMID 19386527

• Not FDA-approved; research-only.
• Long-term human safety is not established.

Stack fit

Why not D: held back by human evidence, preclinical depth, safety clarity, regulatory clarity, practical relevance.

What would move it up: Larger controlled human trials, clearer long-term safety, replicated findings, and regulatory progress.

What would move it down: Failed confirmatory trials, new safety signals, or evidence that popular claims don't translate.

• MOD GRF 1 29 is not FDA-approved for human use; it is discussed in a research context.
• It belongs to the Growth-hormone secretagogues class.
• Its principal mechanism is characterized in the literature.

• Whether observed effects reliably translate to humans at large.
• Long-term safety in healthy users, and full drug-interaction risk.
• Optimal studied parameters outside any approved indication.
• Claim-by-claim verdicts — these are authored against verified sources and shown when complete.
• Quality and purity of material from non-pharmaceutical sources.

1. What it is
2. The GHRH signalling mechanism
3. The early-evidence lane
4. Why Preliminary, and not higher or lower
5. Proven lane vs speculative lane
6. What people report
7. Regulatory status
8. What changed recently