Dr. Betty Murray explains that testosterone, not estrogen, drives sexual desire in both men and women. Women's testosterone levels (15–82 ng/dL) are much lower than men's (300–1,000 ng/dL), which is why women typically have lower sexual motivation. Testosterone creates what she calls "sexual incentive salience" in the brain, the ability to notice and respond to sexual cues.
So let's talk about pathway 1. This is the one most people talk about. It's the one most clinicians attach to, and it's the one that everybody sort of thinks about. And that's testosterone and sexual motivation. So testosterone is the hormone of sexual desire in men and women, not estrogen, right? Estrogen plays a role, but it's much less, much less than testosterone. Women, we have less testosterone than men. And we're talking about 15 to 70 nanograms to up to about 82 nanograms per deciliter, while men have 300 to 1,000. So I just need you to put some math to that. So if our high end is under 100 and men's low end is 300, put that to perspective, right? We never have the same sexual desire because one of the things I hear all the time too is men will say, if I'm you know, talking to a partner or whatever, they'll say, you know, she just never initiates it. And I'm like, our sexual motivation is like a tenth of yours, you know. So we have to remember that. But the main driver of motivation is testosterone, and it drives this impulse to initiate sexual activity. Now, the other thing I like to talk about here is sexual impulse and intimacy and motivation is also what is experienced between the ears. And so your lifestyle situations, which we're gonna talk about in a minute, and all those other things play a role, but testosterone's action is primarily in the brain. And it creates this sexual incentive salience, right? That's the scientific term for it. The ability to notice and be attracted to sexual stimuli.
