Estrogen isn't a molecule. It's a class of feminizing hormones, the most prominent of which is estradiol. Others include estrone and estriol. Collectively, these are called estrogens.

The masculinizing analog for estrogen is androgen (a word you practically never hear*), which also refers to a class of hormones. In addition to being the most well-known of the androgens, testosterone might be the most famous hormone in the whole body**. Dihydrotestosterone is actually the most potent androgen. Androsterone and Androstenedione are (relatively weak) others.

*e.g. It's such an androgen fest!

**Adrenaline is the only competitor that comes to mind.

This moment of pedantry was brought to you by TankieTanuki.