# CJC-1295 Half-Life in the Research Literature > CJC-1295 half life data: the DAC variant has an estimated 5.8-8.1-day half-life with IGF-1 elevation to 28 days; the no-DAC form is short-acting. The pharmacokinetic timeline, sourced. The long-acting DAC form persists for days; the no-DAC form clears in hours. The measured timeline, drawn straight from the human pharmacokinetic studies. ## The measured timeline The published CJC-1295 half life data is variant-specific, and the distinction is the whole point. For the long-acting DAC form, the estimated half-life is 5.8 to 8.1 days in healthy adults, measured in the study that established the compound's human kinetics [1]. For the no-DAC form, Modified GRF (1-29), the half-life is short — minutes to hours — reflecting native GHRH(1-29) clearance with the four substitutions slowing enzymatic degradation but no albumin tether to extend plasma residence [1]. That multi-day figure for the DAC variant is the number the entire long-acting design exists to produce, and it is why the DAC form is dosed far less frequently than the short-acting form. The albumin conjugation is the mechanism; the 5.8-to-8.1-day half-life is the measured result. Every kinetic claim on this page is variant-tagged, because an untagged CJC-1295 half-life figure is meaningless when the two forms differ by orders of magnitude. ## Why the DAC form lasts so long The duration traces to the albumin bioconjugation. The maleimidopropionyl handle on the DAC variant bonds covalently to serum albumin, and albumin is a long-lived plasma protein. By tethering the peptide to it, the conjugate inherits a plasma residence approaching albumin's own, which is what pushes the half-life into days [2]. The rat data made this concrete before the human study: the albumin-conjugated peptide was detectable in plasma beyond 72 hours and produced a 4-fold increase in growth-hormone area-under-the-curve over two hours versus the unconjugated peptide [2]. The four substitutions alone confer protease resistance; the albumin conjugation is what confers the multi-day duration. Remove the conjugation, as in the no-DAC form, and the long half-life disappears [1]. ## IGF-1 outlasts the dose The downstream IGF-1 response extends past the growth-hormone response. In healthy adults, IGF-1 rose 1.5- to 3-fold and stayed elevated for nine to eleven days after a single dose; after multiple doses, IGF-1 remained above baseline up to 28 days [1]. The hormone the analog ultimately raises lingers in circulation well beyond the immediate growth-hormone pulse. That 28-day IGF-1 elevation after repeat dosing is a key part of the kinetic picture and a key part of the safety conversation, because sustained IGF-1 elevation is the basis for the theoretical concerns covered on the FAQ. The [reported and theoretical side effects](/faq) of CJC-1295 are read against exactly this prolonged-elevation profile. ## The no-DAC form clears on a different scale entirely The short-acting no-DAC form, Modified GRF (1-29), occupies the opposite end of the kinetic range. Without the albumin handle, it has no mechanism to extend plasma residence, so its clearance tracks native GHRH(1-29) — minutes to hours — with the four substitutions doing nothing more than slowing enzymatic breakdown [1]. There is no multi-day tail, no 28-day IGF-1 elevation, and no albumin reservoir slowly releasing peptide back into circulation. This is why the variant designation is not a footnote on a half-life page; it is the whole question. A claim of a multi-day half-life belongs only to the DAC conjugate. The same molecule stripped of its DAC handle has a half-life in a different order of magnitude [2]. Any kinetic figure quoted without naming the variant is unreadable, and the [DAC vs no-DAC pharmacokinetics](/dac-vs-no-dac) page exists to keep the two apart. The practical signature of the two profiles is frequency. A compound with a 5.8-to-8.1-day half-life accumulates and persists across days from a single administration; a compound cleared in hours does not. The duration is the differentiator, and it is the differentiator the marketing most often erases. ## What the half-life does not tell you A long half-life describes how long the compound and its downstream hormone persist; it does not describe efficacy, safety, or appropriate use. The pharmacokinetic studies that produced the 5.8-to-8.1-day figure were early-phase human PK work, not efficacy or long-term safety trials [1]. The kinetics are characterized; the clinical outcomes are not. The original long-acting DAC program was discontinued. A ConjuChem Phase 2 trial in HIV-associated visceral obesity was halted, and the DAC program did not advance to approval [1]. CJC-1295 is not approved for human use anywhere, and its multi-day kinetics are a property of the molecule, not a clearance from any regulator. The kinetics also carry a safety dimension that the duration figures make plain. A 28-day IGF-1 elevation after repeat dosing means exposure is not a brief event, and sustained IGF-1 elevation is precisely the profile behind the epidemiologic cancer-risk concern [11]. A long half-life is a pharmacological feature, not a reassurance — it means the system stays activated for longer, for better or worse. This page documents the timeline; it does not recommend acting on it. --- A spatial reading of the published CJC-1295 record — the human pharmacokinetics floated forward, the DAC and no-DAC forms held apart, the data gaps left in plain view, and no clinic, vendor, or prescription behind the glass.