MK-677 and CJC-1295 are often discussed together because both aim to raise the body's own growth hormone rather than supplying it directly. They reach that goal through different mechanisms and routes: MK-677 is an oral non-peptide ghrelin-receptor agonist, while CJC-1295 is an injectable GHRH analog. The most important thing to say up front is that neither is FDA-approved, and the human evidence for both is limited, so this comparison is about contrasting mechanism and route honestly rather than picking a winner.
Reviewed for accuracy · Last reviewed July 8, 2026The core contrast is mechanism and route. MK-677 acts on the ghrelin receptor to prompt growth-hormone release and is taken orally once daily. CJC-1295 is a GHRH analog given by subcutaneous injection, and it comes in two forms: with DAC (long-acting, dosed about weekly) and without DAC, sold as mod GRF 1-29 (short-acting, dosed more often). Both raise GH indirectly rather than replacing it, but they do so through different receptors.
The evidence bases are uneven and limited in different ways. MK-677 has been studied in multi-year and Phase II randomized trials, but those results are sobering: it reliably raised IGF-1 yet did not improve strength or function in older adults, did not slow Alzheimer's progression, and one hip-fracture trial was stopped early over a heart-failure signal. The substantial human data for CJC-1295 is confined to a small early-phase pharmacokinetic study of the with-DAC form, so its clinical effects are not well characterized.
Reported side effects differ by mechanism. MK-677 was associated with increased appetite, water retention, fatigue, and higher fasting glucose with reduced insulin sensitivity, while CJC-1295 reports center on injection-site irritation, flushing, water retention, and tingling. Neither is FDA-approved, long-term safety is not established for either, and none of this substitutes for medical advice.
This page is an independent educational reference and is not medical advice, and does not indicate any approval status for any use. MK-677 is a non-peptide research compound and is not FDA-approved. Talk to a doctor before starting any compound.