A long-acting GHRH analogue in which DAC is an albumin-binding modification rather than a second peptide
Overview
CJC-1295 with DAC is a synthetic GHRH analogue engineered for a long duration of action. From a chemical standpoint, "DAC" is not a further peptide attached to CJC-1295: the letters stand for Drug Affinity Complex, a modification intended to let the molecule bind covalently to circulating albumin and so lengthen its exposure time [1,4]. Referring to "CJC + DAC" is therefore a loose way of describing CJC-1295 DAC. It should also be kept separate from the shorter compounds occasionally labelled "CJC-1295 without DAC" or Mod GRF(1-29), which differ in structure, half-life and the research behind them. CJC-1295 DAC has not been approved by the FDA as a drug. The human studies available were mostly carried out in the early 2000s and measured GH and IGF-1 responses in healthy adults rather than long-term clinical outcomes [1-3].
Biological Mechanism
CJC-1295 DAC attaches to GHRH receptors in the pituitary and prompts somatotroph cells to release growth hormone. Higher GH may in turn raise IGF-1, produced chiefly in the liver though also in other tissues [1]. The DAC carries a chemical group that allows a bond to form with the body's own albumin; once bound, the peptide is cleared less rapidly and remains active for longer than native GHRH or short-acting analogues [1,4]. Lengthening exposure in this way changes how the system behaves. Native GHRH works in brief, pulsatile bursts, while CJC-1295 DAC delivers a more continuous stimulus. One human study reported that some pulsatility in GH secretion survives despite prolonged exposure, yet the resulting profile does not match the normal physiological pattern [2].
Research Evidence
A clinical study in healthy adults, published in 2006, reported that CJC-1295 produced sustained, exposure-dependent increases in GH and IGF-1 that persisted well past the short window associated with native GHRH [1]. A second study from the same period found that GH pulses were not fully abolished despite continuous stimulation [2]. Later work looked at shifts in the serum protein profile after the GH/IGF-1 axis had been activated by CJC-1295, showing that the response extends beyond the two hormones usually measured [3]. Even so, the human studies are small and do not demonstrate clinical benefit in areas such as body composition, recovery, sleep, "anti-ageing" or performance. Elevated GH and IGF-1 indicate pharmacological activity; they are not evidence of a favourable health outcome.
Sustained Exposure Compared with Natural Secretion
GH is released in pulses and is shaped by sleep, nutrition, physical activity, age, somatostatin and GHRH. The relevant question is therefore not simply whether CJC-1295 DAC elevates GH, but how prolonged exposure alters the interplay between these pathways. The finding that some pulsatility is retained is significant, but it does not establish that the overall pattern stays fully physiological [2]. Extended stimulation may shift baseline levels, feedback responses and the length of IGF-1 exposure. The contrast is especially relevant when set against short GHRH analogues, whose exposure is more transient. For that reason, data on CJC-1295 DAC should not be merged with data on short peptides sold under the same trade name.
Safety & Regulation
As part of its review of bulk drug substances for compounding, the FDA assessed several forms of CJC-1295 and CJC-1295 DAC and proposed that they not be added to the 503A list. Its evaluation documents pointed to scarce clinical data, uncertainty over precisely which form was tested in certain studies, and preclinical signals that call for caution [4,5]. The FDA also records serious adverse events reported with CJC-1295, among them raised heart rate and a systemic vasodilatory response, together with concerns about immunogenicity, peptide-related impurities and characterisation of the active substance [5]. A detailed evaluation of CJC-1295 DAC highlighted the absence of long-term carcinogenicity studies and observed that chronic stimulation of the GHRH/GH axis raises theoretical questions about pituitary hyperplasia and growth pathways [4]. This does not prove any specific harm in humans, but it explains why short-term hormonal data alone cannot support a safety assessment.
GH & IGF-1 Markers Are Not Clinical Outcomes
GH and IGF-1 are important biomarkers, but they are not clinical endpoints in their own right. Increases in these markers may coincide with effects on glucose, fluid retention, connective tissue and growth-related systems, so an improvement in overall health cannot be inferred from a hormonal rise. Demonstrating real clinical benefit would require studies measuring function, body composition assessed by validated methods, glucose metabolism, sleep quality, quality of life, cardiac events and long-term safety. No studies of that kind exist at a scale that would allow CJC-1295 DAC to be regarded as an established treatment for the general population.
Summary
CJC-1295 DAC is a long-acting GHRH analogue in which DAC refers to an albumin-binding chemical modification, not a separate peptide [1,4]. Small human studies have reported extended rises in GH and IGF-1, yet there is no broad clinical foundation for long-term benefit, and the FDA has flagged concerns over safety, quality and gaps in the data [4,5]. This material is supplied for laboratory research use only.
Selected Research Sources
- Teichman S.L. et al. Prolonged stimulation of growth hormone and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of growth hormone-releasing hormone, in healthy adults. Journal of Clinical Endocrinology & Metabolism, 2006. PMID: 16352683
- Ionescu M.I., Frohman L.A. Pulsatile growth hormone secretion persists during continuous stimulation by CJC-1295, a long-acting GHRH analog. Journal of Clinical Endocrinology & Metabolism, 2006. PMID: 17018654
- Sackmann-Sala L. et al. Activation of the GH/IGF-1 axis by CJC-1295 results in serum protein profile changes in normal adult subjects. Growth Hormone & IGF Research, 2009. PMID: 19386527
- U.S. Food and Drug Administration. Pharmacy Compounding Advisory Committee briefing document on CJC-1295 and CJC-1295 DAC-related bulk drug substances, December 2024.
- U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. Entry for CJC-1295.
