The ‘Two-Pin’ technique increases sanitation for multiple dose vial users. They draw with the first pin, and then shoot/inject into the body with a new one. This procedure prevents any residual contaminants that may have remained on the drawing pin from being transferred into the body via the injection site. It also makes injection less painful since the drawing needle is necessarily dulled during passage through the rubber stopper atop the vial. A dulled needle increases injection pain because it doesn’t pierce the body as cleanly as an unused one. The protocol below is followed by AAS users who draw from multiple dose vials, but steps 4 - 8 are routinely disregarded by those users who draw from ampoules (also called ampules) and sachets.
It should be noted that in theory if one was to consistently suppress your natural estrogen levels for a long period of time, this would negatively impact your health, including your cholesterol. Due to the ability of Letrozole- to inhibit estrogen so much, this should definitely be a concern to most users. However the research that has focused on the relationship between use of letrozole and cholesterol levels is rather inconsistent in it's findings. Many studies have concluded that the compound is detrimental to both a user's HDL and LDL cholesterol levels, while other research has found no link. Obviously individuals are best served to monitor their cholesterol while using any compound via blood tests however barring that, letrozole should simply not be run for extended periods of time if at all possible. Doing so could cause serious medical complications.
Along with the issues related to blood lipids is the fact that many users complain that their libido is dramatically reduced when using the compound. This is related to the fact that estrogen is partly responsible for the regulation of an individual's sex drive. Since Letrozole- is so potent it can often drive estrogen levels too low and this inhibits a user's libido. To avoid this users can lower dosages, but some anecdotally report that even extremely low doses of the drug can cause problems. If this is the case a less potent compound such as exemestane or anastrozole may be a more appropriate option.