Timing of the daily dose of Glucocorticoids medication to minimize the risk of HPA axis suppression
The body makes 10 to 12 mg/day of cortisol (equivalent to 2.5–3 mg/day prednisone).
Because natural cortisol secretion in humans has a circadian rhythm with the peak level in the morning, taking the GC at that time will have less of a suppressive effect on the release of cortisol-releasing factor and consequently less suppression of the HPA axis.
Additionally, the effect of GC is greater if taken in the morning because its clearance is 25% less.
However, when taking GCs long term, this probably is less important.