Cycling

Cycling means using something in phases: an „on" period followed by an „off" break, often in fixed week-long blocks.

The idea

A common aim is to prevent receptor desensitization (a fading effect/tolerance) by letting receptors „recover" during the break. Whether and how much this is needed depends on the substance and is not proven for all.

Wording mix-ups

Casually a „cycle" or „course"; „on/off" refers to the use and break phases.