Mod-GRF(1-29)

In simple words

Mod-GRF(1-29) is a reinforced version of sermorelin, a short signal for the pituitary gland. It is studied as a way to trigger natural short bursts of growth hormone, especially when paired with ipamorelin.

What this molecule is

29 aa with 4 substitutions vs native GHRH: Tyr¹ (N-terminal stability), D-Ala² (↓DPP-IV), Ala¹⁵ (↓oxidation), Ala²⁷²⁸-NH₂ (↓aggregation). T½ ~30 min. ~3367 Da.

Why it is studied

Stabilized sermorelin analog for physiological pulsatile GH stimulation. The gold standard in combination with Ipamorelin. Mod-GRF (without DAC) = discrete GH pulses = closer to normal physiology.

How it works

Identical to sermorelin: GHRHR → cAMP → GH pulse. Four substitutions: Tyr¹ → stable N-terminus; D-Ala² → resistance to DPP-IV (T½ 30 min vs 7 min for sermorelin); Ala¹⁵ → protects Met from oxidation; Ala²⁷²⁸ → ↓aggregation.

Doses used in studies

Studies used 100-300 mcg SC 2-3 times/day (morning + bedtime + post-workout in some protocols), together with a GHRP peptide (Ipamorelin), for a course of 3-6 months.

Combined with in studies

• Ipamorelin — the classic: GHRH pathway + GHS-R1a pathway
• GHRP-2 — stronger GH pulse, but +cortisol
• Hexarelin — cardio scenario

Level of evidence

Level A Human clinical trials. There are randomized controlled trials (RCTs), or the compound has been approved by a regulatory agency. The most reliable level. RCTs on CJC-1295 with DAC (extrapolation). Mod-GRF without DAC has no RCTs of its own.

Important to know

⚠️ There are no RCTs of Mod-GRF without DAC itself; data are extrapolated from CJC-1295. Not approved. Research only.

Studies in PubMed

1. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. (J Clin Endocrinol Metab, 2006)
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)
3. Effects of [norleucine27]growth hormone-releasing hormone (GHRH) (1-29)-NH2 administration on the immune system of aging men and women. (J Clin Endocrinol Metab, 1997)
4. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. (Endocrinology, 2005)