CJC-1295 half-life & pharmacokinetics

Reported half-life

No-DAC variant: ~30 minutes plasma half-life (sermorelin-equivalent). DAC variant: 6-8 days plasma half-life through covalent albumin binding via the maleimide-modified lysine 30 side chain. The no-DAC form is pharmacokinetically equivalent to Mod GRF 1-29 and preserves pulsatile GH release; the DAC form produces sustained but non-pulsatile receptor activation.

The half-life and pharmacokinetic profile of CJC-1295 reported above is drawn from the published pre-clinical literature. Plasma half-life describes the time taken for the circulating concentration to fall by half after a single dose; tissue half-life — which may be longer for peptides retained in specific organs or matrices — is a distinct and often more relevant parameter for healing research, where the duration of exposure at the injury site matters more than the systemic exposure profile.

Routes of administration studied

• Subcutaneous injection (research; both variants)
• Intramuscular injection (research)

Different routes produce materially different pharmacokinetic profiles for the same peptide. Subcutaneous administration generally produces flatter, more sustained plasma profiles than intravenous bolus dosing; intraperitoneal administration (common in rodent models) is not directly translatable to human routes; oral administration faces the additional challenge of luminal and brush-border peptidase degradation, which is why most research peptides have very low oral bioavailability without protective formulation.

Drug class

Synthetic GHRH (1-29) analogue with four protease-resistance substitutions; available as short-acting (no-DAC) and long-acting albumin-binding (DAC) variants.

Mechanism context

Half-life interpretation depends on the underlying mechanism. CJC-1295 acts as follows:

CJC-1295 is a 30-amino-acid synthetic analogue derived from the biologically active N-terminal 1-29 fragment of human growth-hormone-releasing hormone (GHRH 1-29, sermorelin) through four amino-acid substitutions that confer resistance to enzymatic degradation: D-Ala at position 2 (protects against dipeptidyl peptidase-4, DPP-4, cleavage of the N-terminal His-Ala bond — the principal degradation pathway of native GHRH), Gln at position 8, Ala at position 15, and Leu at position 27. The first three substitutions extend the in-vivo half-life of the underlying GHRH sequence from approximately two minutes (native GHRH 1-44) to approximately 30 minutes (the no-DAC variant, identical to Modified GRF 1-29 or 'Mod GRF 1-29').

See the full CJC-1295 research profile for the complete mechanism summary, history, study citations, and references.

Practical considerations

Short plasma half-life does not necessarily mean short duration of biological effect. Many peptides — including BPC-157, GHK-Cu, and the thymosin-derived compounds — exhibit tissue retention or mechanistic effects (gene expression, signalling cascades) that outlast plasma exposure by hours to days. The pharmacological half-life and the biological-effect half-life are distinct parameters that must both be specified in any rigorous research design. Repeated-dose protocols should account for accumulation only where tissue half-life is genuinely long; for most peptides with short plasma half-life and rapid degradation, accumulation is not a practical concern.

For dose ranges in published research, see the dosing reference page. For reconstitution guidance, see the reconstitution reference page.