Dozens of factors can suppress sexual desire, and they often overlap. Hormonal shifts, common medications, chronic stress, poor sleep, and relationship dynamics all play a role. For many people, low libido isn’t caused by one thing but by a combination of physical, psychological, and lifestyle factors working together.
Hormonal Changes
Sex hormones are the most direct biological driver of desire. In men, testosterone below about 3 ng/mL is the threshold where sexual symptoms, including low libido, become clinically significant. The European Male Aging Study of nearly 3,000 men found that those with total testosterone below 3.2 ng/mL and at least three sexual symptoms (diminished desire, weaker erections, fewer morning erections) met criteria for late-onset hypogonadism. Testosterone naturally declines with age, but the drop is gradual enough that many men never cross that threshold.
In women, the hormonal picture is more complex. Estrogen, progesterone, and testosterone all contribute to desire. Menopause brings a sharp drop in estrogen and a more gradual decline in testosterone, and postmenopausal women have a notably higher rate of clinically low desire than premenopausal women. Low desire is the most common female sexual complaint overall, affecting roughly 8 to 12 percent of women depending on age group, with the highest rates among women aged 45 to 64. Interestingly, while low libido becomes more common with age, the distress it causes tends to decrease, meaning middle-aged women are the group most likely to experience it as a problem they want to solve.
Antidepressants and Other Medications
SSRIs are one of the most well-documented libido killers. These widely prescribed antidepressants suppress desire, arousal, and orgasm by altering serotonin levels in the brain. The rates are striking: in one study, 73 percent of people taking an SSRI reported sexual side effects, compared to just 14 percent on bupropion (a different type of antidepressant). Individual SSRIs vary somewhat, with reported sexual dysfunction rates of roughly 58 to 73 percent across the class. Citalopram and paroxetine tend to score the highest, while fluoxetine and sertraline fall in the mid-to-high range.
If you’re on an SSRI and your desire has disappeared, that’s not unusual or in your head. It’s one of the most common reasons people stop taking their medication, which creates its own problems. Bupropion is frequently used as an alternative because it works through a different brain pathway and has far lower rates of sexual side effects. Switching or adding a second medication is a conversation worth having with whoever prescribes yours.
Hormonal contraceptives can also dampen desire in some women. Birth control pills reduce circulating levels of testosterone, estrogen, and progesterone, and they increase a protein called sex hormone-binding globulin that locks up free testosterone and makes it unavailable. That said, study results are genuinely mixed. Some women notice no change or even an increase in desire (possibly from reduced anxiety about pregnancy). The effect seems to vary by individual, formulation, and the specific hormonal mix in the pill.
Blood pressure medications, antihistamines, certain anti-seizure drugs, and opioid painkillers can also suppress libido through various mechanisms.
Chronic Stress
Stress doesn’t just make you too tired for sex. It actively shuts down the hormonal machinery that produces desire. When your body is in a sustained stress state, it pumps out cortisol, the primary stress hormone. Cortisol directly interferes with the signaling chain that tells your body to produce sex hormones. Specifically, it suppresses the brain’s release of the hormones that trigger testosterone and estrogen production. It also inhibits testosterone synthesis directly in the cells that manufacture it.
This makes evolutionary sense: reproduction is a luxury your body deprioritizes when it perceives a threat. The problem is that modern stressors (work pressure, financial anxiety, caregiving) can keep cortisol elevated for months or years, creating a chronic suppression of the reproductive system. In women, sustained stress hormones can disrupt ovulation and menstrual cycles through the same pathway. The effect is real, measurable, and reversible once stress levels come down.
Sleep Deprivation
Sleep is when your body produces the majority of its daily testosterone. Cut that short and levels drop fast. A study published in JAMA found that young, healthy men who slept only five hours per night for one week saw their daytime testosterone drop by 10 to 15 percent. That’s a significant decline in just seven days. The men also reported a progressive drop in vigor and energy as the week went on, scoring about 30 percent lower by day seven.
At least 15 percent of the U.S. working population regularly gets five hours of sleep or less. If you’re in that group and wondering where your desire went, sleep debt is a likely contributor.
Alcohol
A drink or two can lower inhibition and create a sense of relaxation, which is why people associate alcohol with sex. But regular or heavy drinking does the opposite. Alcohol and its primary metabolic byproduct, acetaldehyde, suppress testosterone in two ways: they reduce production directly in the cells that make it, and they limit the brain signals that tell those cells to keep producing. Heavy drinking also generates oxidative stress that damages the same cells over time. The result is lower circulating testosterone and, eventually, lower desire.
Thyroid Problems
An underactive thyroid slows down virtually every system in the body, and sexual function is no exception. A meta-analysis found that roughly 59 percent of men with hypothyroidism experienced some form of sexual dysfunction, including reduced desire and delayed ejaculation. Women with hypothyroidism report similar issues. Thyroid problems are common, affecting 2 to 6 percent of the general population, and they’re easy to miss because the symptoms (fatigue, weight gain, brain fog, low mood) overlap with so many other conditions. A simple blood test can rule it in or out.
Nutritional Gaps
Vitamin D deficiency has a surprisingly strong connection to low testosterone. A large study of over 2,800 men found that lower vitamin D levels correlated with higher rates of low testosterone. More importantly, a randomized controlled trial showed that overweight men who were deficient in vitamin D experienced a meaningful increase in testosterone after supplementing for one year. The optimal range appears to start at 30 ng/mL, with the best outcomes at 36 to 40 ng/mL. Given that vitamin D deficiency is extremely common, particularly in northern latitudes and among people who work indoors, it’s worth checking.
Zinc plays a supporting role in testosterone synthesis as well. Severe zinc deficiency is uncommon in developed countries, but marginal deficiency is not, especially among vegetarians, older adults, and people with digestive conditions that impair absorption.
Relationship Dynamics
Desire doesn’t exist in a vacuum. Research consistently identifies several relationship factors that predict lower libido: relationship length, low satisfaction, poor communication, and lack of emotional intimacy. Of these, relationship length is one of the most studied. Sexual desire, particularly for women in heterosexual relationships, tends to decline as a partnership moves from its early phase into long-term familiarity. This is normal, but it becomes a problem when the gap between partners’ desire levels grows wide enough to cause conflict.
Unresolved resentment, feeling unappreciated, or emotional distance can suppress desire as effectively as any medication. These factors don’t show up on a blood test, which is why low libido sometimes persists even after hormonal and medical causes are addressed. The psychological dimension is not secondary to the biological one. For many people, it’s the primary driver.
Depression and Mental Health
Low desire is one of the hallmark symptoms of depression, separate from any medication effect. Depression blunts the brain’s reward and pleasure systems, making activities that once felt appealing (including sex) feel neutral or uninteresting. This creates a frustrating catch-22: the condition itself kills desire, and the most commonly prescribed treatments for it do the same. Anxiety disorders can similarly interfere, particularly when they involve body image concerns, performance worry, or a general state of hypervigilance that makes it hard to relax into arousal.
Sorting out whether low libido stems from the mental health condition, the medication, or both often requires some trial and error with treatment approaches. It’s one of the most common clinical puzzles in sexual health.