Anastrozole has no harsh side effects. Actually, affecting estradiol, it can suppress the level of the good cholesterol (HDL). However, when compared to AI like letrozole, anastrozole is preferable. Letrozole has quite a few side effects, the most common of which is erectile dysfunction. Although estradiol is known as a female hormone, men still need it. Estradiol maintains hormonal balance, participates in a great number of physiological processes and helps to gain muscle mass and strength. Such potent AI as letrozole kills almost all estradiol, disrupting the hormonal balance and causing a number of side effects, such as erectile dysfunction, joint pain, bones fragility, unwellness, etc. Anastrozole acts more smoothly and does not kill all estradiol immediately, allowing you to more finely adjust the hormonal balance.