Morning light reaches brain serotonin through the eye. The gut's serotonin does not commute upstairs to become a mood.
Eating late lands the meal when insulin sensitivity is already lower, and the next morning still shows it.
The big growth-hormone pulse rides slow-wave sleep. Going to bed early does nothing if that deep sleep never arrives.
A hand on an arm can raise oxytocin when the touch is wanted. The pulse is a context signal, not a switch.
