Letrozole represent type-II Aromatase Inhibitor.
For the beginning it was developed to be used in medicine and till our time it is used for treating women in their postmenstrual period and against breast cancer.
Letrozole is considered to be one of the most powerful aromatase inhibitor. It attaches to the aromatase enzyme and prevents it from converting androgens to estrogen or in other word this drug blocks the estrogen production.
Because of its proprieties Letrozole became well known in bodybuilding. This supplement help to decrease or eliminate excess of estrogen that often exceed the norm after using aromatizing steroids. It was established that Letrozole reduce level of estrogen for about 98%, in some cases even to undetectable level.