CJC-1295 half-life and pharmacokinetics: what do the studies show?

What is the half-life of CJC-1295?

The estimated half-life of CJC-1295 with DAC is 5.8 to 8.1 days in two randomised, placebo-controlled trials of healthy adults aged 21 to 61; the abstract gives no participant count, and the figure is an estimate for those volunteers, not for any other group or product (Teichman et al., Journal of Clinical Endocrinology & Metabolism, 2006). A half-life is the time a blood level takes to fall by half. A PubMed search on 14 October 2026 found no half-life study of CJC-1295 without DAC.

A half-life is a clock, not a wall. After one half-life, about half of the measured amount remains; after two, about a quarter. For CJC-1295 with DAC, two half-lives add up to roughly 12 to 16 days by simple arithmetic on a range from two healthy-adult trials with no participant count in the abstract, which is a calculation and not a measured time (Teichman et al., 2006). The abstracts read for this page give no time to full clearance.

The range matters. Teichman et al. report 5.8 to 8.1 days from two trials in healthy adults that ran for 28 and 49 days; the abstract gives no participant count, and the estimate says little about any other group (Journal of Clinical Endocrinology & Metabolism, 2006). Which structure each name covers is set out in the with-DAC and without-DAC comparison.

Evidence limits

What has not been published about CJC-1295 pharmacokinetics?

This page reports the half-life range, the fold-changes in growth hormone and IGF-I, and their durations as the papers' abstracts state them. It does not reproduce peak concentrations, times to peak or clearance values.

The people behind the numbers matter. Teichman et al. enrolled healthy adults aged 21 to 61, and Ionescu and Frohman enrolled healthy men aged 20 to 40. Neither abstract gives a sample size, so this page gives none. Both are healthy-volunteer studies, not studies of people with a condition. The CJC-1295 and ipamorelin research guide covers the wider research.

How soon, and for how long, did hormone levels change in CJC-1295 studies?

In two randomised, placebo-controlled trials of healthy adults aged 21 to 61, with no participant count in the abstract, mean growth hormone stayed raised 2- to 10-fold for 6 days or more after one exposure to CJC-1295 with DAC, and mean IGF-I (insulin-like growth factor I, a hormone the liver makes in response to growth hormone) stayed raised 1.5- to 3-fold for 9 to 11 days; these are blood-level results, not clinical outcomes (Teichman et al., Journal of Clinical Endocrinology & Metabolism, 2006). After repeated exposures in the same two trials, mean IGF-I stayed above baseline for up to 28 days, again a blood-level result in healthy adults with no participant count in the abstract (Teichman et al., 2006). One week after one exposure, in healthy men aged 20 to 40 with no participant count in the abstract, overnight sampling found lowest growth hormone levels 7.5-fold higher, mean growth hormone 46% higher and IGF-I 45% higher, a hormone-level result from one study with no clinical outcome (Ionescu and Frohman, Journal of Clinical Endocrinology & Metabolism, 2006).

Hormone levels are not sensations. These studies tracked blood levels, not how a person feels, and the abstracts read give no time to a first change. No study found in the PubMed records searched on 14 October 2026 timed how a person feels or looks after CJC-1295, and none timed CJC-1295 with ipamorelin.

In the overnight study of healthy men aged 20 to 40, with no participant count in the abstract, the frequency and size of growth hormone pulses did not change, and the rise came from higher lowest levels between pulses, a hormone-level result from one study (Ionescu and Frohman, 2006). Your own pituitary gland releases growth hormone in bursts.

How long do the effects of CJC-1295 and ipamorelin last in studies?

Studies measured two different clocks, in separate people. In two randomised, placebo-controlled trials of healthy adults with no participant count in the abstract, CJC-1295 with DAC had an estimated half-life of 5.8 to 8.1 days, and raised growth hormone and IGF-I levels lasted 6 days or more and 9 to 11 days after one exposure, as blood-level results with no clinical outcome (Teichman et al., Journal of Clinical Endocrinology & Metabolism, 2006). In eight healthy men at each of five levels, a study of ipamorelin alone, with no CJC-1295 in it, found a terminal half-life of about 2 hours and a single episode of growth hormone release that peaked at 0.67 hours and fell to negligible levels (Gobburu et al., Pharmaceutical Research, 1999). No study found in the records searched measured the pair together, so none gives a duration for a blend.

Duration figures describe the study products in the study participants. They do not describe a catalogue product or a blend, and the contents of a vial are a separate record, not a study result.

Why does CJC-1295 with DAC stay in the blood for days?

The published design rationale is that CJC-1295 with DAC bonds to albumin, the carrier protein in blood. In male Sprague Dawley rats, with no animal count in the abstract, the added lysine carries a maleimide group that attaches to the free thiol on cysteine 34 of albumin, and the peptide was present in plasma beyond 72 hours; this is an animal result, not a human half-life (Jetté et al., Endocrinology, 2005). In one rat in the same study, a Western blot, a lab test that detects specific proteins, showed a CJC-1295 signal on the albumin band from 15 minutes to beyond 24 hours, a single-animal result (Jetté et al., 2005). Native GHRH, by contrast, had a half-life of 6.8 minutes in normal subjects, with no subject count in the abstract, a result for a different peptide in a different study (Frohman et al., Journal of Clinical Investigation, 1986).

Your blood already carries albumin, a protein that ferries other molecules around. A peptide that bonds to it travels with a long-lived carrier instead of as a small, free molecule, and that is the design idea behind the DAC. In a laboratory test of conjugates made outside the body, albumin conjugates of the GHRH(1-29) backbone showed enhanced stability against dipeptidylpeptidase-IV, an enzyme that clips the front end of GHRH, a result in vitro and not in people (Jetté et al., 2005).

The albumin work was done in rats and rat cells, so it does not establish albumin binding in humans (Jetté et al., 2005). The human half-life estimate comes from a separate study in healthy adults (Teichman et al., 2006).

How does CJC-1295's half-life compare with other GHRH analogues and ipamorelin?

The table compares half-life measurements from separate studies and medicine labels; it does not rank the peptides. Native GHRH had a half-life of 6.8 minutes in normal subjects, with no subject count in the abstract (Frohman et al., Journal of Clinical Investigation, 1986). The tesamorelin labels give 8 minutes for the Egrifta SV formulation and 11 minutes for the Egrifta WR formulation in healthy subjects, and the pharmacokinetics section of each label gives no participant count (Egrifta SV label and Egrifta WR label, DailyMed, effective 29 July 2026, read 14 October 2026). Ipamorelin's terminal half-life was about 2 hours in eight healthy men at each of five levels, in a study of ipamorelin alone (Gobburu et al., 1999). CJC-1295 with DAC had an estimated 5.8 to 8.1 days in two trials of healthy adults with no participant count in the abstract (Teichman et al., 2006). The table below sets the records side by side and ranks nothing.

No study comparing these peptides in the same people was found among the PubMed records searched on 14 October 2026. The native hormone, tesamorelin and ipamorelin figures come from separate studies and labels in different groups of healthy people, so the times are not comparable. The comparison with tesamorelin, ipamorelin and hexarelin sets out what else differs between them.

Do these figures describe research-use CJC-1295?

No. Every half-life figure on this page was measured on a study product in healthy volunteers, or in rats, under study conditions, and none describes a product outside those studies (Teichman et al., Journal of Clinical Endocrinology & Metabolism, 2006; Jetté et al., Endocrinology, 2005). Research-use reference material is a laboratory compound, not a medicine, not a substitute for one, and not for human or animal use. The catalogue lists CJC-1295 (No DAC) and ipamorelin reference material as one blend in a single vial. The published with-DAC half-life does not describe the No DAC form in that vial, and the legal status page records how Australian and US documents treat the name.