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Research Compound GHRH Analogue · No DAC Clinic Preference — Controllable

Mod-GRF 1-29

CJC-1295 without DAC · Modified GRF (1-29) · Tetrasubstituted GHRH 1-29

"The controllable version. CJC-1295 without the Drug Affinity Complex — a 29-amino acid GHRH analogue that peaks in 30 minutes and clears in 3 hours. Preferred by physicians who want predictable GH pulses rather than the sustained week-long elevation of CJC-1295 with DAC."

Structure
29 AA · GHRH analogue · 4 substitutions
Half-life
~30 min (vs 6–8 days for CJC-DAC)
FDA Status
Not approved · research compound
Key advantage
Controllable · stops quickly · clinic preferred
WADA
Prohibited
Protocol summary
Dose
100–300 mcg per injection
Frequency
2–3× daily SubQ
Half-life
~30 minutes
Stack with
Ipamorelin or other GHRP
How we read the evidence
Tetrasubstituted GHRH analog · short half-life mimics natural pulses · the "CJC-1295 without DAC" you actually want · paired with a GHRP for synergy
Animal evidence

Substantial preclinical foundation. Modified GRF (1-29) — also called Mod-GRF or CJC-1295 no-DAC — is a synthetic 29-amino-acid GHRH analog with four amino acid substitutions (D-Ala at position 2, plus three others) that resist enzymatic degradation while preserving GHRH receptor activity. Native GHRH(1-29) (sermorelin) has a half-life of <10 minutes; Mod-GRF extends this to ~30 minutes — long enough for practical dosing while still producing a discrete GH pulse rather than continuous elevation. Animal work (Frohman et al. 2001; Ip et al. 2005; Momany et al. 1981) characterised the receptor binding, the pulse-amplifying effect, and the synergy with ghrelin-receptor agonists.

Community & clinical practice

Community protocols converge on 100–300 mcg SubQ 2–3× daily on empty stomach, paired with a GHRP (ipamorelin most commonly) for synergistic GH pulse — the GHRH receptor and GHS-R1a receptor activate complementary intracellular pathways, producing a GH peak significantly larger than either compound alone. The bedtime dose is most important (synergises with the natural nocturnal GH surge). Cycle 8–16 weeks then break 4 weeks. Mod-GRF is what most users actually want when they say "CJC-1295" — the DAC version (with Drug Affinity Complex bound to albumin, half-life ~6–8 days) produces continuous GHRH-receptor stimulation that doesn't preserve the natural pulsatile pattern. Mod-GRF preserves it.

Human trial data

Foundational pharmacokinetic work in Endocrinology (Ip et al. 2005), Endocrine Reviews (Frohman et al. 2001), and Peptides (Walker et al. 2020). The Teichman 2006 JCEM trial established the DAC version's PK and the Phase 1 safety profile but used the DAC formulation (not Mod-GRF). Mod-GRF specifically has been used widely in pharmacology research as a tool compound for GHRH-receptor characterisation but has not been pursued through formal Phase 2/3 development as a standalone therapeutic. The clinical evidence at the protocol level (Mod-GRF + ipamorelin) is community-derived rather than RCT.

Regulatory status

Not approved by any regulatory agency. Sold via research-peptide vendors and some compounding pharmacies. WADA-banned for tested athletes. Generally well-tolerated at standard doses — main side effects are water retention, mild appetite increase from the paired GHRP, injection-site reactions. The DAC version's regulatory history (CJC-1295 Phase 2 halt 2006 after a participant death attributed to pre-existing CV disease) does not directly apply to Mod-GRF — different formulation, different PK profile, different exposure pattern — but the pharma development pause was the broader signal that ended further trials of the CJC family.

Convergence

Mod-GRF (CJC-1295 no-DAC) is the GHRH analog that actually preserves the natural pulsatile GH pattern — short half-life is a feature, not a flaw. Standard protocol: 100–300 mcg SubQ 2–3× daily paired with ipamorelin (or another GHRP), 8–16 weeks on, 4+ weeks off. The DAC version of CJC-1295 is the better-known name but is the wrong tool for most use cases — continuous GHRH stimulation doesn't mimic biology. Pep IQ flags this honestly: Mod-GRF + ipamorelin is the cleanest GH-secretagogue stack available, well-tolerated in short cycles, but with no formal Phase 3 evidence and unknown long-term safety beyond Phase 1 timeframes.

Community-reported
100 mcg SubQ · 2–3× daily with ipamorelin
Identical to no-DAC CJC-1295
Origin & Background

The controllable GHRH analogue

Mod-GRF 1-29 is a modified version of sermorelin (GHRH 1-29) with four amino acid substitutions designed to improve stability against enzymatic degradation without adding the albumin-binding DAC modification that gives CJC-1295 its 6–8 day half-life. The substitutions replace four amino acids at positions 2, 8, 15, and 27 with amino acids resistant to DPP-4 and other serum peptidases.

The name confusion around this compound is notorious — it is frequently sold as "CJC-1295" when it is in fact CJC-1295 without DAC. True CJC-1295 has the Drug Affinity Complex modification that extends its half-life to 6–8 days. Mod-GRF 1-29 lacks this modification, giving it a half-life of approximately 30 minutes — comparable to sermorelin but with greater stability than unmodified GHRH 1-29.

Clinicians increasingly favour Mod-GRF 1-29 over CJC-1295 (with DAC) for several reasons: the shorter half-life is more controllable — if a patient has side effects, the peptide clears within hours rather than persisting for a week. It also allows more physiological pulsatile GH patterns when dosed 2–3 times daily alongside a GHRP, rather than the sustained continuous elevation produced by CJC-1295 DAC.

The naming confusion: Many suppliers sell Mod-GRF 1-29 labelled as "CJC-1295 without DAC" — which is technically accurate but creates confusion with CJC-1295 (with DAC), which has a fundamentally different half-life and dosing protocol. When purchasing, confirm which version you have: if it requires daily or 3x daily dosing, it is Mod-GRF 1-29. If it is weekly, it is CJC-1295 with DAC.

Science & Mechanism

Four substitutions — same receptor

Mechanism of Action

1
GHRHR binding: Mod-GRF 1-29 binds the same GHRH receptor as sermorelin and CJC-1295, stimulating pulsatile GH release from pituitary somatotrophs. The mechanism is identical — only the pharmacokinetics differ.
2
Four amino acid substitutions: Position 2 (Ala→D-Ala), position 8 (Asn→Gln), position 15 (Gly→Ala), position 27 (Met→Nle). These substitutions confer DPP-4 resistance and improve overall peptide stability without albumin binding.
3
30-minute half-life: Without the DAC albumin-binding modification, Mod-GRF 1-29 peaks at 30 minutes and is largely cleared within 2–3 hours. This produces a clean, defined GH pulse rather than the sustained elevation of CJC-1295 DAC.
4
Physiological pulsatile pattern: When dosed 2–3 times daily with a GHRP, Mod-GRF 1-29 mimics the natural GHRH + ghrelin pulsatile GH release pattern more closely than once-weekly CJC-1295 DAC. Some practitioners consider this more physiological.
5
Synergy with GHRPs: Same powerful synergy as CJC-1295 — combined with ipamorelin, GHRP-2, or GHRP-6, produces 3–5x more GH than either compound alone. The short half-life means the synergy window is the 30–60 minutes around injection rather than a sustained multi-day effect.
Benefits & Evidence

What the data shows

🎛️
Controllable GH pulse — physician preferred
The 30-minute half-life means GH elevation is predictable and time-limited. If side effects appear, stopping the compound resolves them within hours rather than the days-to-weeks required for CJC-1295 DAC to clear. This controllability is the primary clinical advantage.
● Moderate — pharmacokinetic rationale
💉
GH/IGF-1 elevation and body composition
Same downstream effects as sermorelin and CJC-1295 — GH elevation drives IGF-1, which drives lean mass gain, fat loss, improved recovery and sleep. The body composition evidence is extrapolated from the class rather than specific to this compound.
● Moderate — class extrapolation from GHRH analogue data
🔁
Physiological pulsatility (potential advantage)
Multiple daily injections with Mod-GRF produce GH release in defined pulses — more closely mimicking natural GH secretion patterns than the sustained elevation from weekly CJC-DAC. Whether this pulsatility advantage translates into better clinical outcomes has not been formally studied.
● Limited — theoretical advantage, not tested head-to-head
💤
Sleep and recovery (consistent reports)
Bedtime Mod-GRF + ipamorelin injection produces an acute GH pulse during early slow-wave sleep — the most common protocol reported to improve sleep quality and recovery. Effect is well-characterised in community reports.
● Moderate — consistent across community reports
Safety First

Risks & considerations

🛡️
Safer class profile than CJC-1295 with DAC. The short half-life means side effects can be managed by stopping the compound — they resolve quickly rather than persisting for days. Same class risks as all GHRH analogues, but with better reversibility.
Mild
Injection site reactions — standard SubQ injection reactions. Less frequent per-dose than CJC-DAC since the injection burden is higher (3x daily vs weekly).
Mild
Flushing and headache — transient, typically first 2 weeks. More acute per-injection than CJC-DAC due to sharper GH pulses.
Moderate
Water retention and joint discomfort — less than CJC-1295 DAC for most users due to lower sustained IGF-1 elevation, but still present at higher doses.
Moderate
IGF-1 monitoring required — same as all GH secretagogues. Monitor every 3 months and keep within age-appropriate range.
Serious
Contraindicated in active malignancy — same class contraindication as all GH axis stimulants.

⚠ Key Warnings

Confirm what you have — "CJC-1295 without DAC" and Mod-GRF 1-29 are the same compound, but some suppliers mislabel CJC-1295 with DAC as "without DAC." If dosing is once weekly it is the DAC version regardless of label.
3x daily injection protocol requires compliance and sterile technique at every injection. More injection events means more infection risk if technique is not meticulous.
WADA: prohibited at all times for all competitive athletes.
Honest Assessment

Editor's summary

Mod-GRF 1-29 is neither better nor worse than CJC-1295 with DAC — it is different in a way that matters clinically. The shorter half-life gives physicians and users the ability to stop and see effects resolve quickly, rather than being committed to a week-long GH elevation after each injection. This controllability is genuinely valuable in a clinical context.

The practical downside is the injection burden — three daily injections vs once weekly for CJC-DAC is a significant compliance difference. For self-injecting community users, this is often the deciding factor. For medically supervised protocols where physician confidence in dose control matters, Mod-GRF is increasingly the preferred option.

Combined with ipamorelin (the standard clinic protocol), Mod-GRF 1-29 provides the same GH synergy as CJC-1295/ipamorelin with more predictable and controllable pharmacokinetics. The body composition and sleep effects are consistent with the rest of the GHRH analogue class.

Verdict
"The physician's choice for GHRH — controllable, predictable, and reversible. Same GH synergy with ipamorelin as CJC-1295 DAC, but with a 30-minute half-life that allows dose adjustments and side effect management. The compliance cost of 3x daily injections is the trade-off."