A low sex drive in men is surprisingly common and almost always has an identifiable cause, whether physical, psychological, or some combination of both. It’s rarely about attraction to a partner, even though that’s the first place many people’s minds go. Understanding the real reasons can help you both figure out what’s going on and what, if anything, to do about it.
Low Testosterone Is the Most Common Physical Cause
Testosterone is the primary hormone driving sexual desire in men. When levels drop below the normal range of roughly 193 to 824 ng/dL, one of the earliest symptoms is a noticeable dip in sex drive, often before any other signs appear. Over time, low testosterone (sometimes called hypogonadism) can also cause fatigue, depressed mood, difficulty concentrating, and trouble getting or maintaining erections.
Testosterone naturally declines with age, typically dropping about 1% per year after 30, but younger men can have low levels too. Causes include chronic illness, obesity, pituitary gland problems, certain genetic conditions, and even prior use of anabolic steroids. If your boyfriend also seems unusually tired, moody, or has lost muscle mass, low testosterone is worth looking into. A simple blood test can measure it.
Medications That Quietly Kill Libido
Several widely prescribed medications reduce sex drive as a side effect, and many men don’t connect the dots. The biggest culprits are antidepressants, particularly SSRIs like fluoxetine (Prozac) and sertraline (Zoloft). These medications alter brain chemistry in ways that dampen desire and can make orgasm difficult or impossible. Anti-anxiety medications like diazepam and lorazepam do the same.
Blood pressure medications are another common cause. Thiazide diuretics (water pills) are the most frequent offenders, followed by beta-blockers like propranolol and metoprolol. Even finasteride, a popular hair loss treatment, is known to reduce libido in some men. If your boyfriend started a new medication in the months before his drive dropped, that’s a strong lead. These side effects are often manageable by switching to a different drug in the same class, but he should never stop a medication without talking to his prescriber first.
Stress, Anxiety, and Depression
Mental health is one of the most underestimated factors in male sex drive. Chronic stress from work, finances, or family pressures raises cortisol levels, which directly suppresses testosterone production and makes the body prioritize survival over reproduction. The effect is real and measurable, not just “being too tired.”
Depression is particularly destructive to desire. Low self-esteem, hopelessness, and physical fatigue all drain interest in sex. Anxiety creates its own vicious cycle: if a man has had trouble with erections or finishing too quickly (or too slowly), performance anxiety builds around sex itself. Each negative experience reinforces the worry, and the worry makes the next experience worse. Eventually, avoiding sex altogether feels easier than facing the anxiety. Past sexual trauma, including abuse or assault, can also suppress desire in ways that surface years later.
Sleep and Weight Matter More Than You’d Think
Sleep deprivation has a direct, measurable impact on testosterone. A study from the University of Chicago found that men who slept only five hours a night saw their testosterone levels drop by 10 to 15 percent. That’s a significant decline from just a few nights of poor sleep, and many men are chronically under-sleeping without realizing the hormonal cost.
Excess weight compounds the problem. Obesity raises the risk of vascular disease and diabetes, both of which impair blood flow and nerve function needed for arousal. Fat tissue also converts testosterone into estrogen, further lowering the hormones that drive desire. The numbers are striking: according to Harvard Health, a man with a 42-inch waist is 50% more likely to have erectile problems than one with a 32-inch waist. If your boyfriend has gained weight, sleeps poorly, or both, these factors alone could explain a lot.
Diabetes deserves special mention. High blood sugar damages the nerves and blood vessels involved in erections, and men with diabetes are significantly more likely to develop sexual difficulties. Sometimes erectile dysfunction is the first warning sign of undiagnosed blood sugar problems.
Relationship Dynamics Play a Role
This is the hardest part to examine honestly, but relationship patterns genuinely affect desire. Research from the University of the Basque Country found that people who feel emotionally secure with their partner have more satisfying sex lives, while those dealing with insecurity, avoidance, or controlling dynamics experience more conflict around sexual desire. The most difficult combination is when one partner is anxious (clinging, seeking reassurance) and the other is avoidant (pulling away, shutting down). This pairing tends to escalate over time.
Unresolved conflict, lack of trust, feeling criticized, or emotional distance can all suppress a man’s desire even when he’s otherwise physically healthy. Men are often socialized to process relationship dissatisfaction through withdrawal rather than conversation, so a drop in sexual interest can be his way of expressing something he doesn’t have words for yet.
What Actually Helps
The most effective first step depends on what’s driving the problem. If he’s on medication that’s known to affect libido, a conversation with his doctor about alternatives is the fastest path to improvement. If stress, poor sleep, or weight are factors, lifestyle changes make a real difference. Thirty minutes of daily walking alone was linked to a 41% reduction in erectile dysfunction risk in one Harvard study, and moderate exercise helped restore sexual function in middle-aged men who were overweight.
Diet matters too. A pattern of eating fruits, vegetables, whole grains, and fish was associated with lower rates of sexual dysfunction in the Massachusetts Male Aging Study. Vitamin D deficiency specifically has been linked to a 30% higher risk of erectile problems, and chronic vitamin B12 deficiency can damage nerves involved in sexual sensation. These aren’t miracle cures, but they address the underlying vascular and hormonal health that makes desire possible.
For psychological causes, the path forward usually involves some form of therapy, whether individual (for depression, anxiety, or trauma) or couples-based (for relationship issues). If performance anxiety has become part of the cycle, a therapist who specializes in sexual health can help break it.
How to Bring It Up
The way you raise this topic matters enormously. Men often feel deep shame around low libido because it conflicts with cultural expectations about masculinity, so framing the conversation as “something is wrong with you” will almost certainly backfire. Instead, approach it as something you want to work on together.
Before you talk, spend some time reflecting on your own emotions around the situation. Journaling about what comes up when you think about your sex life together can help you separate hurt feelings from blame, so you can express what you’re experiencing without putting him on the defensive. Phrases like “I’ve noticed we haven’t been connecting physically as much, and I miss that” land very differently than “Why don’t you want to have sex with me?”
Be open to hearing that the cause might be something you weren’t expecting: his job, a medication, body image issues, or something in the relationship he hasn’t known how to raise. If stress is a factor, think about whether there are practical responsibilities you could redistribute. If the issue feels too big to work through alone, couples counseling gives you a structured space to talk about it without it turning into a fight. The goal is to be on the same team, not opposite sides of a problem.