A drop in sexual desire is one of the most common sexual health concerns, and it almost always has an identifiable cause. Among midlife women alone, roughly 69% report low desire, and about a third experience enough distress about it to meet the clinical threshold for a sexual desire disorder. Men experience it too, though it’s reported less often. The reasons range from hormonal shifts and medications to relationship dynamics and sleep, and most of them are treatable once you know what you’re dealing with.
Hormones Play a Central Role
Sexual desire is heavily regulated by hormones, and even modest changes can shift how often you think about or want sex. Testosterone is the primary driver of libido in both men and women. When levels drop, desire tends to follow. In men, low testosterone can result from aging, chronic illness, obesity, or certain medications. In women, testosterone also matters, but estrogen is equally important. As estrogen declines, particularly during perimenopause and menopause, desire often drops alongside it.
Perimenopause, which lasts an average of four years but can stretch to eight, brings falling estrogen levels that affect desire both directly and indirectly. Vaginal dryness and discomfort during sex make the experience less appealing, which compounds the hormonal effect. This isn’t a switch that flips overnight. It’s a gradual shift that many women don’t immediately connect to hormonal changes.
Thyroid problems are another common but overlooked hormonal culprit. An underactive thyroid is linked to decreased libido in both sexes. In men, hypothyroidism can lower testosterone, cause erectile problems, and delay ejaculation. In women, it affects arousal and the ability to reach orgasm. An overactive thyroid creates its own set of sexual difficulties. If your low desire arrived alongside fatigue, weight changes, or feeling unusually cold or warm, your thyroid is worth checking.
High levels of prolactin, a hormone usually associated with breastfeeding, can also suppress desire in both men and women. This can happen with certain medications or, less commonly, with a benign pituitary growth.
Medications That Suppress Desire
If your interest in sex dropped after starting a new medication, that’s likely not a coincidence. Antidepressants are the most well-known offenders. SSRIs and similar drugs cause sexual dysfunction in 36% to 43% of people taking them, with effects that include reduced desire, difficulty with arousal, and trouble reaching orgasm. By comparison, bupropion, a different class of antidepressant, causes sexual side effects in only about 22% to 25% of users. In people without other risk factors for sexual problems, taking an SSRI makes you four to six times more likely to experience sexual dysfunction than taking bupropion.
Beyond antidepressants, blood pressure medications, hormonal birth control, anti-seizure drugs, and opioids can all dampen libido. If you suspect a medication is the cause, the fix may be as simple as switching to a different drug in the same class or adjusting the dose.
Stress, Sleep, and Mental Health
Your brain is your most important sexual organ, and when it’s overwhelmed, desire is one of the first things to go. Depression itself reduces interest in pleasurable activities across the board, sex included. Anxiety floods your system with stress hormones that compete directly with the hormonal signals that drive desire. This creates a frustrating loop: the condition suppresses your libido, the most common treatment for the condition can also suppress your libido, and the distress about losing your libido makes everything worse.
Sleep deprivation has a measurable biological effect. A meta-analysis of studies on sleep and testosterone found that going 24 hours or more without sleep significantly reduces testosterone levels in men. Going 40 to 48 hours without sleep drops them even further. While a single short night doesn’t appear to have a major hormonal impact, chronic sleep restriction, the kind most people actually deal with, grinds down your energy, mood, and interest in sex over time even if each individual night isn’t catastrophic.
Smoking also suppresses testosterone, adding another layer for people already dealing with stress or poor sleep.
Relationship Dynamics and Habituation
Long-term relationships naturally experience a cooling of sexual intensity. This isn’t a personal failing. It’s a well-documented psychological pattern called habituation. The novelty and excitement that fuel early desire gradually fade as a relationship becomes familiar and predictable. Research from psychologist Arthur Aron at the American Psychological Association describes this as a loss of “self-expansion,” the sense that a relationship helps you grow and experience new things.
Boredom is a real and specific problem. Aron’s lab studies found that couples who did novel, exciting activities together (not just pleasant, routine ones) had noticeably more positive interactions afterward and reported better sex lives. The mechanism works because shared novelty reactivates some of the same feelings of discovery that characterize early attraction. If your relationship feels like it’s running on autopilot, that sameness may be a bigger factor in your low desire than anything happening in your body.
Unresolved conflict, resentment, feeling unappreciated, or a mismatch in emotional intimacy can also quietly erode desire. For many people, especially women, emotional connection is a prerequisite for wanting sex, not a byproduct of it. When that connection breaks down, desire doesn’t just decline. It can disappear entirely.
When Low Desire Becomes a Disorder
Not everyone who experiences low desire has a clinical condition. The diagnostic threshold requires two things: a persistent or recurrent absence of sexual desire or fantasies, and significant personal distress or relationship difficulty because of it. If your desire is low but you’re not particularly bothered by it, that’s a normal variation in human sexuality, not a disorder.
But if the loss of desire is causing you real distress, it’s worth naming what’s happening. In a large community study of women aged 40 to 65, about 32% met the criteria for hypoactive sexual desire disorder, meaning they had both low desire and significant distress about it. Even among women who weren’t in a relationship or sexually active, nearly a third reported distress about their sexual situation.
What Can Actually Help
The right approach depends entirely on the cause. If hormones are the issue, hormone therapy can include estrogen, progesterone, or testosterone replacement depending on the situation. For premenopausal women with a clinical desire disorder, two FDA-approved non-hormonal options exist: one is a daily pill, and the other is a self-administered injection taken about 45 minutes before sex. In clinical trials, these medications showed modest improvements in desire scores compared to placebo, though the most common side effects include sleepiness, dizziness, and insomnia.
For medication-related libido loss, the solution often involves working with your prescriber to try an alternative. Switching from an SSRI to bupropion, for example, dramatically lowers the odds of sexual side effects.
If the cause is psychological or relational, therapy tends to be more effective than medication. Couples therapy can address the emotional disconnection that kills desire. Individual therapy, particularly cognitive behavioral approaches, can help untangle the anxiety-depression-libido knot. And sometimes the most effective intervention is surprisingly simple: doing something new and genuinely exciting with your partner. Not dinner at the usual place, but something that creates a sense of shared adventure. The research consistently shows this reignites both emotional connection and sexual interest.
Addressing sleep, exercise, and stress isn’t glamorous advice, but these factors form the biological foundation that desire depends on. You can’t optimize hormones or relationship dynamics on four hours of sleep and chronic overwhelm.