Ticks said:
For anyone weighing evening versus morning dosing, particularly alongside reta, my research points to the following.
1. GH pulse amplitude drives IGF-1 output, and insulin from a meal suppresses that pulse at the pituitary — therefore preserving the fasted state takes priority over preserving circadian alignment.
2. Timing doesn't matter much for IGF-1 regardless (its half-life is long, it aggregates GH exposure over the whole day, and it reaches steady state across roughly 2 weeks), so a morning injection sacrifices essentially nothing in terms of "nocturnal synergy." That's why the trade-off clearly leans toward morning fasted instead of being a toss-up.
3. There is 1 boundary condition: a clean fasted window at night could let night come out slightly ahead through synergy — so "morning wins" holds only when the night option is under-fasted, not as an absolute rule.
4. Retatrutide doesn't reverse this. Slower gastric emptying slightly strengthens the case for morning-fasted as the cleanest window, and better insulin sensitivity supports the pulse. The new variable it brings in — deficit-driven hepatic GH resistance reducing IGF-1 — operates independently of when you inject, so the timing conclusion stays the same.
The caveat - Important one IMO
1. GHRH-receptor signaling directly promotes slow-wave sleep through the preoptic/anterior hypothalamus, separately from GH release.
2. That effect is time-locked — the agonist needs to be centrally active around sleep, which a short-half-life peptide only manages with an evening dose.
3. It's specific to the GHRH receptor, not a GH/IGF-1 effect (the GHRP-2 dissociation), so the mechanism is coherent rather than simply "more GH → better sleep."