Study wrapper · #249
Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog.
Editor's note
A well-designed human study and one of the more informative in the CJC-1295 record. In healthy men aged 20–40, researchers sampled GH every 20 minutes over a 12-hour overnight window before and one week after a single 60 or 90 µg/kg injection, specifically to test whether continuous GHRH-receptor stimulation flattens the body's natural pulsatile GH rhythm. It did not: pulse frequency and amplitude were unchanged, while basal (trough) GH rose sharply (7.5-fold), lifting mean GH ~46% and IGF-1 ~45%. Notably, the IGF-1 rise did not correlate with any GH secretion parameter, and the two doses produced similar responses. The finding that pulsatility is preserved is mechanistically reassuring and clinically relevant, since pulsatile GH is thought to matter physiologically. Caveats: small sample, healthy young men only, single dose, short follow-up, surrogate endocrine endpoints rather than clinical outcomes. This strengthens the pharmacodynamic case that CJC-1295 durably raises GH and IGF-1 while sparing rhythm, but it does not establish benefit or safety for any body-composition or performance use.
Plain-language abstract
Growth hormone (GH) is normally released in bursts, or pulses, and this rhythmic pattern is thought to matter for its effects. This study asked whether a long-acting GH-releasing drug that stays active for about a week would flatten out these natural pulses. CJC-1295 attaches permanently to a blood protein (albumin) after injection, giving it a half-life of roughly eight days. The researchers measured GH by taking blood every 20 minutes over a 12-hour overnight period in healthy men aged 20 to 40, before and one week after a single injection of either 60 or 90 micrograms per kilogram of body weight. After the injection, overall GH release went up, but the natural pulses were preserved: the number and size of the GH bursts stayed the same. What changed was the baseline (lowest) GH level between bursts, which jumped about 7.5-fold. This raised average GH by about 46% and IGF-1 (a marker of GH activity) by about 45%. The IGF-1 rise did not track with any measure of GH pulsing, and the two doses gave similar results. The study was small and short, tested only healthy young men, and measured hormone levels rather than any health outcome. No adverse events were highlighted in the abstract.