Letrozole is sometimes used in bodybuilding to control estrogen levels. It's an aromatase inhibitor that can help prevent estrogen-related side effects during certain phases of a bodybuilding cycle. Dosage The dosage of Letrozole can vary, and it should be determined based on individual needs and response to the medication. Bodybuilders often use it in the range of 0.25 to 2.5 milligrams per day.