Low libido rarely has a single cause. It typically results from a combination of hormonal shifts, stress, sleep habits, medications, and relationship dynamics that together dampen sexual desire. Understanding which factors apply to you is the first step toward addressing it.
How Stress Directly Suppresses Desire
Chronic stress is one of the most common and underappreciated causes of low libido. When you’re under sustained pressure, your body keeps producing elevated levels of cortisol, the primary stress hormone. Cortisol and testosterone work against each other in a kind of biological tug-of-war. Research from the University of Texas at Austin found that chronically elevated cortisol inhibits testosterone production in men and can produce severe fertility problems and abnormal menstrual cycles in women.
This antagonism makes evolutionary sense. Your body treats ongoing stress as a survival threat, and mating behaviors get deprioritized when survival is in question. The problem is that modern stressors, like financial pressure, caregiving, overwork, or relationship conflict, can keep cortisol elevated for months or years. That prolonged hormonal imbalance quietly erodes sexual desire without an obvious “cause” you can point to. Many people who visit a doctor expecting a hormonal diagnosis are actually experiencing stress-driven suppression of their sex hormones.
Hormonal Changes in Men and Women
Testosterone is the primary hormone driving sexual desire in both sexes, though women need far less of it. In men, the American Urological Association defines low testosterone as a total level below 300 ng/dL. But hitting that threshold alone doesn’t confirm testosterone is the problem. The diagnosis requires both documented low levels and symptoms like reduced sex drive, fatigue, or mood changes. Decreased desire can also stem from chronic fatigue or depression rather than a true testosterone deficiency, which is why testing matters.
For women, hormonal shifts around menopause are a major trigger. As estrogen levels decline, vaginal tissues become thinner and drier, a condition called vaginal atrophy. This can make sex uncomfortable or painful, which understandably reduces desire over time. Lower hormone levels also directly decrease sex drive independent of any physical discomfort. These changes can begin during perimenopause, sometimes years before periods stop entirely.
Hormonal contraceptives can also lower libido in some women by reducing the amount of free testosterone circulating in the body. This effect varies widely from person to person, and switching formulations sometimes helps.
Sleep Loss Has a Measurable Effect
Sleep deprivation hits testosterone levels faster than most people realize. A study from the University of Chicago found that healthy young men who slept just five hours a night saw their testosterone drop by 10 to 15 percent after only one week. That’s a significant decline from a relatively modest amount of sleep restriction, the kind many people consider normal during busy stretches of life.
Poor sleep also raises cortisol, compounding the hormonal problem. If you’ve noticed your desire fading during a period of disrupted or shortened sleep, that connection is likely real, and it’s one of the more reversible causes of low libido.
Medications That Lower Sex Drive
Several common medications can suppress libido as a side effect. The most well-known culprits are antidepressants, particularly SSRIs, which affect the brain chemistry involved in arousal and desire. Some people notice reduced libido within weeks of starting these medications, while others develop it gradually over months.
Other medications that can interfere with sexual desire include blood pressure drugs (especially beta-blockers), opioid pain medications, anti-seizure medications, and hormonal treatments like certain birth control pills or drugs used for prostate conditions. If your libido dropped after starting a new medication, that timing is worth discussing with your prescriber. Alternatives or dosage adjustments often exist.
How Diabetes and Other Conditions Play a Role
Chronic health conditions can erode libido through multiple pathways at once. Type 2 diabetes is a good example. Prolonged high blood sugar damages blood vessels and nerves involved in sexual response. In women, it also decreases vaginal lubrication and increases infection risk, making sex less comfortable. In men, the vascular damage contributes to erectile difficulties, which often leads to avoidance of sex and a gradual decline in desire itself.
The key mechanism is that sustained high blood sugar causes cellular damage through oxidative stress and a process that stiffens blood vessel walls. This impairs blood flow to genital tissues and disrupts the nerve signaling that transmits sexual sensations. Keeping blood sugar levels stable, rather than letting them spike and crash, helps protect against this kind of damage.
Thyroid disorders, particularly an underactive thyroid, can also suppress libido by slowing metabolism and causing fatigue. Depression and anxiety lower desire both through their direct effects on brain chemistry and through the medications used to treat them.
Relationship and Psychological Factors
Desire doesn’t exist in a vacuum. Unresolved conflict, emotional distance, resentment, or feeling unseen by a partner can quietly shut down sexual interest even when your hormones and health are fine. For people in long-term relationships, the shift from spontaneous desire (wanting sex out of the blue) to responsive desire (becoming interested only after physical or emotional cues begin) is normal and common, but it can feel like something is wrong if you’re expecting desire to work the way it did early in the relationship.
Body image, past sexual trauma, performance anxiety, and guilt or shame around sex are all psychological factors that suppress desire. These causes often coexist with physical ones, making it hard to untangle which came first. A therapist who specializes in sexual health can help sort through these layers in a way that blood work alone cannot.
When Low Libido Becomes a Clinical Diagnosis
Not every dip in desire qualifies as a disorder. The diagnostic criteria used by clinicians require symptoms to persist for at least six months and to cause significant personal distress. For women, the formal diagnosis of Female Sexual Interest/Arousal Disorder requires at least three of the following: absent or reduced interest in sexual activity, few or no sexual thoughts or fantasies, little initiation of sex and low receptivity to a partner’s initiation, absent or reduced pleasure during sex in most encounters, reduced response to sexual cues, and reduced physical sensations during sex.
That six-month threshold exists because temporary drops in desire are a normal part of life. Stress, illness, new parenthood, grief, and major life transitions all cause short-term changes in libido that resolve on their own. The clinical label applies when the pattern becomes persistent and genuinely bothers you, not your partner, not a cultural expectation, but you personally.
Treatment Options That Exist Today
Treatment depends entirely on the cause. If blood work reveals low testosterone in men, hormone replacement can restore desire in many cases. For women experiencing menopause-related changes, localized estrogen therapy can address vaginal dryness and discomfort, which in turn can help desire recover.
There are also two FDA-approved medications specifically for low sexual desire in women. Flibanserin, first approved in 2015 for premenopausal women, works on brain pathways involved in desire rather than on hormones directly. In January 2026, the FDA expanded its approval to include postmenopausal women under 65. A second option, bremelanotide, is self-injected before anticipated sexual activity and works through a different brain pathway.
For stress-related or sleep-related causes, the most effective interventions are lifestyle changes: consistent sleep of seven or more hours, regular physical activity (which boosts testosterone and lowers cortisol), stress reduction practices, and addressing the underlying sources of chronic pressure. These changes aren’t instant fixes, but they target the root mechanisms rather than masking symptoms. Exercise in particular has strong evidence for improving desire in both men and women, partly through hormonal effects and partly through improved mood and body image.
Cognitive behavioral therapy and sex therapy have good track records for psychological causes, especially when desire issues are tied to anxiety, trauma, or relationship patterns. For couples, working with a therapist together can address the dynamic between partners rather than framing low libido as one person’s problem to fix.