Whenever you’ve looked at an attractive person and pictured what a night together might be like, or whenever you’ve waited until you’ve had the house to yourself and then fired up the computer for some “personal time,” it was your testosterone that was responsible. This little hormone plays a vital role in a man’s body by helping to regulate the sex drive. The testicles secrete it, and it helps to keep everything relating to sex within the body working and in check.

But your testosterone levels aren’t always going to be through the roof. Inevitably your testosterone levels will begin to falter, and your sex drive will feel the effect. The testosterone levels within the body begin drop at 40, with experts finding that a man’s testosterone tends to drop about 1.3% every year after 40.

If you find that sex has suddenly become less interesting, or that you often feel tired, or if your moods have been all over the place, this might be a result of low testosterone levels. In addition to throwing moods and sexual feelings into flux, low testosterone levels can also make it difficult for the body to achieve an erection.

The erection depends upon testosterone, with the hormone alerting the penis when it’s time to get to work. But if your testosterone levels dip, your penis might get the wake up call it needs, which translates into missed erections.

If you’re dealing with low testosterone levels, talk to your doctor about how this issue can properly be addressed. With medication, you should be able to get your testosterone back to a normal level, your sex drive should return, and your erection will be ready to get back to work.