Glossary
Cycling
Also written on cycle, off cycle, washout
Running a compound for a defined period and then stopping for one, rather than taking it continuously.
Two different reasons get called cycling and they are worth separating. One is receptor desensitisation, the concern that continuous exposure reduces the response. Well established for some receptors, assumed for others. The other is simply limiting total exposure to a compound whose long-term effects are unknown.
The second reason applies to almost everything on this site and does not need the first to be true.
Cycle lengths in circulation, eight weeks on and four off and similar, are conventions rather than findings. Almost none of them come from a study that compared them against continuous use.
Relevant compounds