Modified GRF(1-29)
Modified Growth Releasing Factor 1-29 (Tetrasubstituted GRF)
A stabilized analog of the first 29 amino acids of GHRH with four amino acid substitutions that prevent enzymatic degradation, extending the half-life from ~2 minutes to ~30 minutes while preserving full GHRH receptor activity.
Mechanism of Action
Modified GRF(1-29) binds GHRH receptors on pituitary somatotrophs with high affinity, stimulating GH release in a pulsatile fashion when combined with a GHRP. The four substitutions (at positions 2, 8, 15, and 27) prevent DPP-IV and other protease cleavage, dramatically improving stability.
Health Claims & Evidence
Stimulates pulsatile GH release mimicking natural secretion
Synergistic GH release when combined with GHRPs
Improves body composition and recovery
Short-Term Effects
Improved sleep quality and recovery within 1–2 weeks.
Long-Term Effects
Progressive improvement in body composition, skin quality, and energy over 8–16 weeks.
Side Effects
Water retention, mild joint discomfort, transient flushing. Generally well-tolerated.
Contraindications
Active malignancy, diabetic retinopathy. Use with caution in insulin resistance.
This profile is provided for educational research only. It is not a treatment recommendation or dosing guide. Human evidence, safety information and regulatory status vary by substance. Verify primary sources and consult a qualified healthcare professional for medical decisions.
Research Papers
Modified GHRH analogs and GH secretion
Bowers et al. · Journal of Clinical Endocrinology & Metabolism · 1998
Educational research only. This profile is not a treatment recommendation or dosing guide. Human evidence, safety information and regulatory status vary by substance. Consult a qualified healthcare professional for medical decisions.
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