It is well known in UK that Clenbuterol (Clenbuterol Hydrochloride) use results in rapid down-regulation of beta 2 receptors. This is due to the powerful stimulatory effect of the drug. It is therefore pointless to use Clen for long periods without a break. Some UK athletes believe that a two day on, two day off dosing schedule will allow adequate potential for receptor up-regulation. However, there are doubts that this to be the case due to the relatively long half life of Clen 20mcg, resulting in continued stimulation even throughout the ‘off’ days. A much better regime would be a two week on, two week off cycle. Maximum plasma levels are reached around 2-3 hours after oral administration, and terminal half life at 34 hours.
A tapering up of dosages is recommended in an attempt to limit harsh side effects. Most commonly, a user will start by taking one 20mcg tablet on day 1, followed by an increase of one tablet on subsequent days. Subject to personal tolerance levels, a dosage of 120mcg-140mcg (six-seven tabs) will be used by day 7, and this level should be maintained for the entire second week. It would be fruitless to exceed seven or eight tablets daily due to receptor over-saturation. There is no requirement to taper down.
For the next ‘cycle’ of clen (i.e. weeks 5 & 6), there is no requirement to taper up from one tablet as your tolerance level should now be known. As an example, if the user finished the first cycle of clen on 7 tabs, they could recommence at a slightly lower dose of 4 or 5, and taper up again from this level. Again though, the user should again limit their intake to 7 or 8 tabs daily.
During the two ‘off’ weeks, an ECA stack can be used as required. ECA will not cause such a pronounced down regulation and desensitization of the receptors, certainly not to the extent of clen. Ephedrine has a short half life in contrast to clen which results in times throughout the day where the betas will partially recover from stimulation by adrenaline and nor-adrenaline. Potency is also much weaker that that of clen, as it is not a specific agonist. Ephedrine is also thought to increase the conversion of endogenous/exogenous T4 to T3 through the activation of deiodinase enzymes responsible for this process. This is important as clen is known to slow the rate of T4 to T3 conversion. As a side note, some bodybuilders will use T3 concurrently with the Clenbuterol/ECA cut