Originally Posted by
Motardpdx
It has been reported as having a half life of about 2 days, but that is not actually correct, since it has biphasic elimination, with the half-life of the rapid phase being about 10 hours, and the slower phase being several days. Supposedly, this is one of the reasons the FDA never approved clenbuterol as an anti-asthmatic drug...the FDA frowns on drugs with long half-lives if drugs with more normal half-lives are available. So with a 2-on/2-off cycle you never have time to get enough of the clenbuterol out of your system for this theory to be reasonable. In actuality, it probably hasn't even dropped to 50% of your peak concentration before you are taking the drug again. With this all taken into account, there is no reason to think that this cycling would significantly reduce the problem of receptor desensitization. A more reasonable approach would be either one week on, one week off, or alternately, two weeks on two weeks off. The two week cycle has the disadvantage of a "crash" period afterwards. This crash period can be helped with the use of ephedrine to lessen the lethargy that you will experience.