Letrozole is a powerful Aromatase Inhibitor that was developed to fight breast cancer. For athletes and bodybuilders, it is a drug used to combat the estrogenic side effects of anabolic steroids water-retention, acne and gynocomastia. It will also raise testosterone levels because of the lowered estrogen in the body. Side effects from Letrozole include a lowered sex drive and continuous use can lead to lowered lipid function and an impaired immune system.
Letrozole also does quite a few things that would be of interest to both bodybuilders and athletes. Firstly, it has been shown to reduce estrogen levels by 98% or greater (1). In at least one documented incident, Letrozole reduced test subject estrogen to undetectable levels, while increasing LH, FSH and SHBG (4). For the bodybuilder, less estrogen in the body means less chance of estrogen-related side effects. This makes Letrozole an appropriate choice for even the heaviest bulking or cutting cycles, including those which incorporate harsher androgens. Also, if you are a competitive bodybuilder, Letrozole is a must have product for contest preparation as no other ancillary compound supports the coveted dry and tight appearance quite as well.
How good is Letrozole when compared with Aromasin (Exemestane) and Arimidex (Anastrozole), its primary rivals? Letrozole is 10-20x more potent than Anastrozole, and about as potent (but with a slightly different mechanism) as Exemestane. It also long-lasting. Letrozole has a whopping 2-4 day half-life, and youll need to take Letrozole for approximately 60 days (with wild variance of 2-6 weeks) to achieve a steady blood plasma level.