September 30, 2026 · 2 min read

CJC-1295: a long-acting GHRH analogue and the growth hormone axis

A summary of the clinical pharmacology papers on CJC-1295, a long-acting GHRH analogue, covering half-life, GH and IGF-I responses, and pulsatility.

CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH), engineered to stay in the body far longer than the natural hormone, which is cleared within minutes. These are the pharmacology papers behind it.

The problem it was built to solve

GHRH makes the pituitary release growth hormone (GH), and GH raises insulin-like growth factor I (IGF-I) in the liver. As a research tool, GHRH itself is limited by how briefly it acts. CJC-1295 has a chemical modification that lets it bind albumin, a long-lived protein in blood.

Why a longer-acting analogue

  1. 1

    GHRH

    Signals the pituitary to release growth hormone.

  2. 2

    Growth hormone

    Raises IGF-I in the liver.

  3. 3

    The limit

    Natural GHRH acts only briefly.

  4. 4

    CJC-1295

    Binds albumin after administration, so it persists for days.

Simplified from the cited pharmacology papers. Illustrative only.

Healthy adults

A 2006 paper in the Journal of Clinical Endocrinology and Metabolism reported two randomized, placebo-controlled, double-blind ascending-dose trials in healthy adults aged 21 to 61. After a single injection, mean GH concentrations rose 2- to 10-fold for six days or more, and IGF-I rose 1.5- to 3-fold for 9 to 11 days. The estimated half-life was 5.8 to 8.1 days. After repeated doses, mean IGF-I stayed above baseline for up to 28 days. No serious adverse reactions were reported.

How long the changes lasted after dosing

  • Mean GH raised (at least)6 days
  • Mean IGF-I raised (9 to 11 days)upper end11 days
  • Estimated half-life (5.8 to 8.1 days)upper end8.1 days
  • IGF-I above baseline after repeat doses (up to)28 days
From Teichman et al., J Clin Endocrinol Metab 2006, healthy adults. Bars show the upper end of each reported range or the stated minimum; see the text for the full ranges.

Pulses survive

GH is normally released in pulses, and that pattern is thought to matter for its effects. A companion study sampled blood every 20 minutes overnight in healthy men, before and one week after an injection. GH secretion went up and the pulses were preserved. Their frequency and size didn't change, but the baseline between pulses rose about 7.5-fold. The authors suggested that higher baseline is what drives the IGF-I increase.

Animals and detection

In mice lacking GHRH, once-daily CJC-1295 normalized growth. Analytical chemists have also published methods for detecting synthetic GHRH analogues for anti-doping control, using mass spectrometry in the same way batch identity testing does.

Limits

The human data are short studies in healthy volunteers, and the outcomes are hormone levels. They describe pharmacology, not clinical benefit. The name CJC-1295 is also used for more than one chemical form on the market, so the certificate of analysis should state the exact structure and whether it carries the albumin-binding modification.

References

  1. Teichman SL et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab 2006.
  2. Ionescu M, Frohman LA. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab 2006.
  3. Alba M et al. Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse. Am J Physiol Endocrinol Metab 2006.
  4. Memdouh S et al. Advances in the detection of growth hormone releasing hormone synthetic analogs. Drug Test Anal 2021.

Related research notes