A drop in sex drive is one of the most common health concerns people search for, and it rarely has a single cause. Hormones, medications, stress, sleep, relationship dynamics, and chronic health conditions can all lower sexual desire, sometimes several at once. Understanding which factors apply to you is the first step toward figuring out what to do about it.
Hormones Play a Central Role
Testosterone is the hormone most directly tied to sexual desire in both men and women. In adult men, normal levels range from about 193 to 824 ng/dL, while in adult women they sit below 40 ng/dL. Even within those ranges, being on the lower end can reduce desire noticeably. Men’s testosterone naturally declines with age, roughly 1 to 2 percent per year after 30, and when levels fall below the normal range, low sex drive is one of the earliest and most common symptoms.
Women experience their own hormonal shifts. During perimenopause and menopause, falling estrogen levels reduce blood flow to the genitals, thin vaginal tissue, and decrease natural lubrication. These changes can make sex uncomfortable, which in turn reduces interest. After childbirth, elevated prolactin levels (the hormone responsible for milk production) suppress desire and contribute to vaginal dryness. Most women have little to no libido immediately after delivery, and it can take six months or longer to return to baseline, especially while breastfeeding.
Thyroid problems also matter. An underactive thyroid slows metabolism broadly, causing fatigue and depressed mood that drag desire down with them. An overactive thyroid can disrupt sexual function too, likely through hormonal cascading effects and the anxiety it generates.
Stress Directly Suppresses Desire
When you’re stressed, your body releases cortisol, a hormone that shifts your nervous system into a fight-or-flight state. This is essentially the opposite of the relaxed, safe state your brain needs to generate sexual interest. Cortisol redirects your brain’s attention toward threat detection and away from pleasure-seeking. It also alters activity in the prefrontal cortex, the part of the brain involved in approaching sexual stimuli in the first place.
This isn’t just about feeling “too busy” for sex. Chronic stress physically changes how your brain processes arousal cues. A disruption in your body’s stress-hormone system can dysregulate several homeostatic processes, including sexuality. People dealing with ongoing work pressure, financial worry, caregiving responsibilities, or grief often find that desire doesn’t just dip temporarily. It stays low until the underlying stress load changes.
Poor sleep amplifies this. Sleep deprivation raises cortisol, lowers testosterone, and leaves you too exhausted to feel interested. If you’re getting fewer than six hours consistently, that alone could explain a significant drop in desire.
Medications Are a Common Culprit
If your sex drive dropped around the time you started a new medication, that’s worth paying attention to. Antidepressants are the most well-known offenders. All antidepressants carry some risk of sexual side effects, but the ones that affect serotonin carry the highest risk. SSRIs like paroxetine, sertraline, fluoxetine, and escitalopram are the most likely to reduce desire, dampen arousal, or make orgasm difficult. Among them, paroxetine has the highest rate of sexual side effects. SNRIs like venlafaxine pose similar risks.
Some antidepressants are less likely to cause these problems. Bupropion, mirtazapine, vilazodone, and vortioxetine have the lowest rates of sexual side effects. If you suspect your medication is the issue, it’s worth discussing alternatives with your prescriber rather than stopping on your own.
Antidepressants aren’t the only medications that affect libido. Hormonal birth control can lower free testosterone levels and reduce desire in some women. Blood pressure medications, particularly older classes like beta-blockers, are also known to interfere. Antihistamines, opioid painkillers, and some anti-seizure drugs round out the list of common contributors.
Chronic Health Conditions
Diabetes affects sexual function through multiple pathways. It increases the risk of depression, which is the single strongest predictor of low sexual desire. It can also cause nerve damage that dulls sensation, impair blood flow to the genitals, and increase the likelihood of vaginal infections and pain during sex. High blood sugar over time damages small blood vessels, and the genital area is particularly sensitive to that kind of vascular impairment. High blood pressure causes similar vascular problems.
Obesity lowers testosterone in men, partly because fat tissue converts testosterone into estrogen. It can also reduce self-image and physical stamina, both of which feed into lower desire. Heart disease, chronic pain conditions, and autoimmune disorders create similar cascading effects: fatigue, medication side effects, mood changes, and body image concerns all compound to suppress libido.
Your Relationship Matters More Than You Think
Physical desire is heavily influenced by emotions. If your relationship is strained, sex will be too. Intimacy in long-term relationships naturally evolves over time, and unresolved conflict, poor communication, or emotional distance can erode desire even when nothing is physically wrong. The dynamic is reciprocal: how one partner behaves affects how the other responds, and negative patterns can become self-reinforcing.
This doesn’t mean something is broken. It means desire in a long-term relationship requires different conditions than it did in the early months. Novelty, emotional connection, feeling appreciated, and having space for vulnerability all feed sexual interest. When those elements fade, desire tends to fade with them. Couples who address communication patterns directly, sometimes with the help of a therapist, often see desire return as the emotional climate improves.
Mental Health and Body Image
Depression and anxiety are among the most reliable predictors of low libido, independent of any medication effects. Depression blunts the brain’s reward system broadly, making activities that once felt pleasurable (including sex) feel flat or uninteresting. Anxiety keeps the nervous system in a state of heightened vigilance that competes directly with arousal.
Body image plays a quieter but powerful role. Feeling uncomfortable or self-conscious about your body makes it hard to relax into sexual experiences. This is true across genders, though it’s more frequently studied in women. Weight changes, aging, surgical scars, and postpartum body shifts can all trigger self-consciousness that suppresses desire even when physical health is fine.
How Low Libido Gets Evaluated
If you bring up low sex drive with a doctor, expect a conversation about your medical history, medications, stress levels, sleep, and relationship before any lab work. When blood tests are ordered, the basic screen typically includes testosterone and prolactin. For the most accurate result, testosterone is measured as a “free” level (the amount actually available to your body) from a blood draw taken in the morning, when levels peak.
If testosterone comes back low, follow-up tests can help pinpoint where the problem originates. Levels of luteinizing hormone and follicle-stimulating hormone reveal whether the issue is in the testes or ovaries themselves, or in the brain signals that control them. Thyroid function is commonly checked as well, since both overactive and underactive thyroid can interfere with desire.
Not every case of low libido needs a blood test, though. When the cause is clearly situational (a new medication, a stressful life period, a relationship in conflict, postpartum recovery), addressing that root cause is the more direct path. Many people find their desire rebounds once the circumstances shift, without any medical intervention at all.