Researchers haven't unraveled the mystery of just how testosterone increases libido. It's normal for a man's sex drive to slowly decline from its peak in his teens and 20s, but libido varies widely between men. What one man might consider a low sex drive, another might not. Also, sex drive changes within each man over time and is affected by stress, sleep , and opportunities for sex. For these reasons, defining a "normal" sex drive is next to impossible. Usually, the man himself identifies a lack of sex drive as a problem. Other times, his partner may consider it to be an issue.
Unlike estrogen, androgen levels don't suddenly drop when you reach natural menopause. Instead, androgen production begins slowly falling in your twenties. By the time you reach menopause, you're producing about half as much as you made at puberty. However, your ovaries may still continue to produce small amounts of androgens even after menopause. Some studies show menopausal ovaries continue to produce testosterone; other studies show they do not. One thing is for sure: if your ovaries are removed or damaged, you will go into surgical or early menopause. Some women who experience surgical menopause report a drop in sexual desire and drive.