The axis, briefly
The GH axis is a feedback loop. The hypothalamus releases growth-hormone-releasing hormone (GHRH) and ghrelin, which tell the pituitary to release growth hormone. Growth hormone travels to the liver, which produces IGF-1. Rising IGF-1 tells the hypothalamus to slow down.
That loop is why the axis is described as pulsatile rather than steady. Growth hormone is released in bursts, and the largest burst of the day occurs during deep sleep. Anything that disrupts deep sleep disrupts that burst.
Why secretagogues are dosed at night
Growth-hormone secretagogues act on this loop rather than replacing it. Ipamorelin stimulates the ghrelin receptor; CJC-1295 no-DAC stimulates the GHRH receptor. Timing a dose before sleep places the induced pulse where the natural pulse already sits, which is the reasoning behind the near-universal convention.
The same logic explains the fasting guidance. Insulin and glucose suppress growth-hormone release, so a dose taken shortly after a meal produces a smaller pulse. The standard advice to dose away from food is physiology, not ritual.
What this does and does not do
The hormone response is real and documented. Controlled studies of GH secretagogues show dose-dependent increases in growth hormone and IGF-1, and the ipamorelin-plus-CJC-1295 combination produces a larger pulse than either alone.
What is not documented is the thing people actually want: that raising growth-hormone pulsatility for a few months produces meaningful changes in body composition, recovery or ageing in healthy adults. That bridge has not been built in human trials. It is an assumption drawn from what growth hormone does, not a finding.
The mechanism is proven. The outcome is assumed. Those are different claims and it is worth keeping them separate.
The case for doing the boring things first
Sleep architecture, protein intake, resistance training and consistent circadian timing all influence the same axis, and the evidence for them is considerably stronger than for any peptide.
- Sleep duration and depth govern the largest natural GH pulse of the day. A secretagogue cannot compensate for a chronic sleep deficit — it adds a signal on top of a damaged one.
- Resistance training is the stimulus that gives growth-hormone elevation something to do. Elevated GH without mechanical load does not produce muscle.
- Protein sufficiency determines whether tissue repair has raw material available.
Adding a secretagogue to a poor sleep and training pattern is the most common way people in this space spend money for no result.
What to watch
Raising IGF-1 has consequences. The most relevant practical marker is fasting glucose — GH elevation can worsen insulin sensitivity in susceptible individuals, and this shows up before anything else does. If fasting glucose drifts upward on consecutive readings, that is a signal to stop and reassess rather than push through.
Anyone with active cancer, proliferative retinopathy, or untreated pituitary disease should not use these compounds at all. Growth hormone and IGF-1 promote cell proliferation; that is their normal function, and it is exactly why they are inappropriate in those contexts.
Where to go next
If you want the compound-level detail — reported doses, half-lives, side-effect profiles and the primary sources — start with the Ipamorelin dossier and the CJC-1295 dossier. If you want to understand how they are structured together, the stacking guide covers the reasoning.