Most of it is treatable. Start there.

Because desire runs on hormones that are falling, and on sleep, mood and comfort that are falling with them. Estrogen decline thins tissue and makes sex hurt for many women, and pain is the fastest libido killer there is. Testosterone, which women make and need, has usually been sliding since the late twenties. Add broken sleep and a stressed nervous system, and low desire is the predictable output of the whole system, not a personal failing. Which piece leads matters, because each one is treatable.

For many women, yes. It has been a special interest of mine since 2009, long before it was fashionable. Women make testosterone too, and it drives desire, arousal, energy and muscle in them just as it does in men. It works on the brain as well, shaping mood, motivation and thinking through its effects on neurotransmitter systems and brain signaling pathways. Treated women often notice the clearer head and the better mood along with the desire. The evidence is strongest for postmenopausal women with low desire that bothers them. It is prescribed off-label in the United States, which is a gap in the system rather than a verdict on the treatment, and dosing must be physiologic and monitored. Managed properly it is neither miracle nor menace. And it is no borrowed male hormone: in a young healthy woman it is her most prevalent sex hormone, at four to ten times the level of her estradiol.

After menopause the most common cause is genitourinary syndrome of menopause: estrogen loss thins and dries the tissue, and unlike hot flashes it worsens with time rather than passing. Vaginal estrogen treats it directly and is dramatically underused. It is more than dryness when pain persists despite lubrication and local estrogen, when it is deep rather than at the entrance, or when it comes with bladder symptoms or pelvic muscle spasm. Those patterns point toward pelvic floor dysfunction or other conditions that deserve their own workup, not a bigger tube of lubricant.

It is treatable, and it is the most common male sexual complaint at every age. Lifelong PE is largely wiring, involving serotonin signaling, and it responds to medication strategies alongside behavioral ones. Newly acquired PE deserves a look for a cause. Most men suffer with it for years before mentioning it to anyone, which is the real tragedy, because the treatments work and the conversation takes ten minutes.

The most common cause I find is a medication, with serotonin-based antidepressants at the top of the list. After that come diabetes, which quietly injures the nerves involved, performance anxiety, low arousal, alcohol, and changes after pelvic surgery. Some men have orgasms with no visible semen because it travels backward into the bladder, which is harmless but alarming when nobody has explained it. The list of causes is long, and that is good news, because a cause that can be named can usually be treated. This is a fixable problem far more often than men assume, and the workup starts with a conversation, not a procedure.

Delayed ejaculation and anejaculation, in depth →

Because desire is not a lab value. Testosterone is one input into one of the most complex systems you own. Desire draws on your hormones, your sleep, your stress and anxiety, your medications and alcohol, your metabolic health, and your history: a man who has struggled before starts watching himself instead of wanting, and the watching kills the wanting. It is also physical in a way most men never hear about. Erections depend on blood vessels, nerves and the regular arrival of oxygen-rich blood, and when the machinery falters, desire quietly follows it down. This is why I take a full history before I order anything, and why a normal number is the beginning of the conversation rather than the end of it. Something is causing it. Normal labs just narrow the list.