What it is: A synthetic version of the hormone that signals your pituitary gland to release growth hormone, available in a short-acting form and a long-acting albumin-binding form.
Research suggests: Human studies confirm it reliably increases GH and IGF-1 levels; the combination with a GHRP like ipamorelin is among the most studied GH optimization approaches.
Best for: Growth hormone optimization researchers
Key thing to know: The DAC version has an approximately 8-day half-life; the non-DAC version (Modified GRF 1-29) produces shorter GH pulses more similar to natural rhythms.
What is CJC-1295?
CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH), the signal that triggers pituitary growth hormone release. It comes in two forms: CJC-1295 without DAC (Modified GRF 1-29), producing a short GH pulse of 30 minutes to a few hours, and CJC-1295 with DAC (Drug Affinity Complex), which binds albumin to extend its half-life to roughly eight days.
Researchers have studied CJC-1295 for sustained elevation of growth hormone and IGF-1 levels, body composition improvement, fat reduction, and recovery, most commonly in combination with Ipamorelin, where the two compounds work through complementary receptor pathways to amplify GH output beyond what either achieves alone.
How it works.
In research, the proposed mechanism has several parts.
GHRH analog: Your hypothalamus naturally releases GHRH in pulses to signal the pituitary gland to produce and secrete growth hormone. CJC-1295 mimics this signal by binding to GHRH receptors on the pituitary, triggering GH production through the body's own gland, preserving the normal feedback mechanisms that regulate how much GH is produced.
Without DAC: The without-DAC version (Modified GRF 1-29) closely mirrors the natural GHRH pulse: it binds, triggers a GH release event, then clears relatively quickly. It's the form typically paired with Ipamorelin — Ipamorelin triggers the GHS-R receptor while CJC-1295 without DAC triggers the GHRH receptor, amplifying GH output through two pathways at once.
With DAC: The with-DAC version works differently: the Drug Affinity Complex modification lets it reversibly bind albumin (a carrier protein), greatly slowing its breakdown. Think of the without-DAC form as a strong GH signal per injection, and the DAC version as a slow-release signal that keeps the pituitary producing GH across the week.
What the research shows.
The research evidence breaks down as follows.
Human PK/PD data: Published human pharmacokinetic and pharmacodynamic studies on CJC-1295 with DAC document significant, sustained elevation of GH and IGF-1. A key study showed dose-dependent increases that persisted up to 28 days after a single injection — a profile unlike most compounds in this class. That makes it one of the more clinically documented GH secretagogues in humans.
Evidence focus: However, the published evidence focuses mainly on GH and IGF-1 changes rather than downstream clinical outcomes. Large long-term randomized controlled trials on body composition, recovery, aging endpoints, or outcomes in healthy populations have not been conducted. The Ipamorelin combination is well-documented in practice, but its published RCT base is limited compared with the individual-compound data.
Evidence level: The evidence profile is Moderate: human data confirming the primary pharmacological effect (GH and IGF-1 elevation) is published and meaningful, but the connection between these hormonal effects and specific clinical outcomes in diverse populations has not been established at the level of large-scale trials.
Biomarkers to review first.
Research protocols for CJC-1295 typically reference the following biomarkers as baseline context. Testing these before exploring this peptide gives you and your healthcare provider the most relevant starting information.
See the full lab testing guide →What it's commonly researched with.
CJC-1295 is most extensively studied in combination with Ipamorelin, where the GHRH-receptor and GHS-receptor pathways work in concert. This pairing is one of the most frequently cited combinations in GH secretagogue research literature. The entries below represent what appears in the research literature, not combinations to pursue without clinical supervision.
Goals & biomarkers connected to this peptide.
Go deeper
A research overview of the baseline biomarkers used to establish context before exploring peptide research, viewed through a longevity lens.
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