CJC-1295 vs MK-677: Research Comparison | Regena Peptides

CJC-1295 is a truncated 30-residue GHRH analogue with four amino-acid substitutions that increase resistance to DPP-4 degradation. The 'with DAC' variant adds a maleimidopropionic-acid modification for covalent albumin binding and multi-day half-life; the 'no DAC' variant is the unmodified short GHRH analogue.

MK-677 (ibutamoren) is a non-peptide small molecule that acts as an orally active agonist at the growth-hormone-secretagogue receptor (ghrelin receptor / GHS-R1a). It drives GH release through the ghrelin axis rather than the GHRH axis, and is administered orally rather than by injection.

CJC-1295 is selective for the GHRH receptor. Downstream growth-hormone release follows the natural pulsatile pituitary pattern in research models, and the IGF-1 response follows the GH signal.

MK-677 is selective for the ghrelin receptor, engaging the same GHS-R axis as ipamorelin but with oral bioavailability and a substantially longer duration of action — sustained ghrelin-axis activation is characteristic of MK-677 in published research.

CJC-1295 no DAC has a short-to-medium half-life (daily research cadence). CJC-1295 with DAC has a multi-day half-life (weekly research cadence) driven by covalent albumin binding.

MK-677 has a reported half-life of approximately 24 hours and is dosed once daily orally in published research. The oral route and long duration make it a fundamentally different research tool from the injectable GHRH analogue.

CJC-1295 is used in GHRH-axis research, in growth-hormone secretagogue panels paired with ipamorelin, and in any research design requiring pulsatile GH release through the natural hypothalamic-pituitary axis.

MK-677 is used in research models requiring sustained ghrelin-axis activation, in oral-bioavailability research designs, and in longer-term chronic-exposure research where injection cadence is a design constraint.

Both CJC-1295 and MK-677 ship from Regena only after independent third-party verification — Janoshik Analytical is the default verifier, with orthogonal independent laboratories used when batch chemistry calls for confirmation by a second method. Minimum release specification is ≥99.0% HPLC main-peak purity with matching mass-spectrometry molecular weight and water content within the published specification for the compound.

Batch COAs for both compounds are published on the Regena lab reports page so a research-peptide buyer can audit the analytical detail before purchase. The /trust/how-to-read-a-coa reference walks through every field on a modern Regena COA.

CJC-1295 ships lyophilised under nitrogen; hold at 2–8 °C, freeze at −20 °C for long-term storage, and reconstitute with bacteriostatic water. MK-677 ships as a solid or oral-solution research kit; storage conditions are cool and dry, protected from light. Both compounds support standard research-cadence handling.

Aliquot before any freeze. The single most common cause of measurable potency loss in research peptides is repeat freeze-thaw cycling — both CJC-1295 and MK-677 benefit from single-thaw aliquot workflows. Vortex gently, never shake aggressively, and keep reconstituted vials away from direct light. The /research/compound-storage-guide reference covers the per-compound stability windows in detail.

Researchers choose CJC-1295 when the protocol targets the GHRH receptor arm specifically or when pulsatile GH release is central to the experimental design. Researchers choose MK-677 when sustained oral ghrelin-axis activation is the experimental requirement — chronic-exposure metabolic, body-composition or sleep-architecture research models. Matched panels sometimes include both compounds in separate arms to isolate the axis contribution.

For multi-compound comparator studies, the Regena consultations team will reserve matched-batch inventory of both CJC-1295 and MK-677 against a project timeline so the experimental panel is sourced under a single analytical specification window.

Both CJC-1295 and MK-677 are supplied strictly for in-vitro and preclinical research use. They are not medicines, are not approved for human consumption in Spain, the United Kingdom, the European Union or the United States, and are not dispensed against a prescription. The research-use declaration ships with every package alongside the independent third-party COA.

Comparison pages on the Regena site exist for laboratory-research reference. Nothing on this page constitutes a recommendation for human use of either compound.