Low sex drive in men: the causes worth checking first
Medication, sleep, alcohol, mood and testosterone all lower desire. How to work out which one is yours, and what a doctor can actually do about it.
Interest in sex falls for reasons that are usually boring and often fixable. That is the useful news buried under an industry built on the opposite claim.
The men who get somewhere with this treat desire the way they would treat any other symptom: work through the short list of likely causes, in order of how common they are, and stop guessing.
Start with what changed
Desire that has drifted down over a decade and desire that fell off a cliff in March are different problems.
So before anything else, place it in time. When did you last feel normal? What else started around then: a new prescription, a promotion, a baby, a stretch of bad sleep, a relationship going quiet, weight gain, a diagnosis? The answer to that question does more diagnostic work than any blood test in this article.
The causes worth checking first
The NHS list is the sensible starting point: relationship difficulties, stress, anxiety or depression, sexual problems such as erectile dysfunction, falling hormone levels with age, certain medicines including antidepressants and drugs for high blood pressure, hormonal contraception in a partner, and drinking too much. Long-term conditions including heart disease, diabetes, an underactive thyroid and cancer also lower desire (NHS).
Notice how much of that list is not hormonal. Most men arrive convinced this is a testosterone problem, and for most of them it is not.
Medication is the most missed cause
If your libido changed within weeks of a new prescription, start there rather than at a hormone panel.
Antidepressants are the clearest example. A meta-analysis of trial data put rates of treatment-emergent sexual dysfunction between 25.8% and 80.3% depending on the drug, with sertraline, venlafaxine, citalopram and paroxetine at the high end. Several others, including bupropion and mirtazapine, were no different from placebo (J Clin Psychopharmacol, 2009).
The width of that range matters, because it means the effect belongs to the specific drug rather than to treatment in general. A switch is often possible.
A 2026 systematic review of randomized trials separates which part of sex the drugs hit. Against placebo, SSRIs roughly tripled the risk of difficulty reaching orgasm (RR 3.28, 95% CI 2.33 to 4.60, three trials), while the effect on desire itself was smaller and did not reach statistical significance (RR 1.40, 95% CI 0.92 to 2.12, four trials) (Eur J Clin Pharmacol, 2026). If desire is the thing that has gone and the timing fits a new prescription, it is still worth raising, but the drug is a less certain culprit than it is for orgasm.
Two rules go with this. Do not stop a prescribed medicine on your own, and do not assume your doctor knows it is bothering you unless you say so. Sexual side effects are consistently underreported, largely because nobody raises them in a ten-minute appointment.
Blood pressure medicines belong in the same conversation, as do opioids and anabolic steroids, both of which Cleveland Clinic names as causes of a low level (Cleveland Clinic).
Sleep, alcohol and weight
These three are the levers you control, and they act on desire through more than one route.
Sleep is the fastest. Ten healthy young men who spent eight nights on less than five hours in bed lost 10% to 15% of their daytime testosterone (JAMA, 2011). Even leaving hormones aside, exhaustion is not a state that generates much interest in anything.
Alcohol cuts both ways. It lowers inhibition in the evening and flattens desire over months, and heavy use is on the NHS list for exactly that reason.
Weight works through hormones. Across 24 studies, men who lost weight on a low-calorie diet gained about 2.87 nmol/L of total testosterone, roughly 83 ng/dL (Eur J Endocrinol, 2013). Our guide to raising testosterone naturally ranks these levers by how much each is actually worth.
Is it testosterone?
Sometimes, and desire is one of the better reasons to check.
Unlike tiredness or low mood, reduced libido is among the symptoms that genuinely track testosterone, particularly when it arrives with fewer morning erections. The Testosterone Trials, the largest randomized study of treatment in older men with levels below 275 ng/dL, found that sexual function including desire improved over a year, while vitality and fatigue did not (NEJM, 2016).
The asymmetry is useful. A man whose only complaint is fatigue is unlikely to be helped by hormones, while a man whose desire and erections both faded has a real reason to test.
If you are going to test, do it properly. A morning sample, repeated on a second morning, read against your own laboratory's range. Signs of low testosterone separates the complaints that carry hormonal weight from the ones that do not, and the testosterone blood test guide covers timing, repeats and units. If a confirmed deficiency turns up, the honest account of treatment is in our guide to testosterone replacement.
Desire, erections and mood are three different things
Men tend to collapse these into one complaint, and doctors then have to unpick it.
| What you notice | What it usually points at | Where to start |
|---|---|---|
| No interest, but erections work when interest appears | Stress, relationship, sleep, medication, mood | The timeline and the medicine list |
| Interest intact, erections unreliable | Blood vessels, nerves, anxiety | Our guide to erectile difficulty and a cardiovascular check |
| Both faded together, plus fewer morning erections | Worth a hormone check | Morning testosterone, repeated |
| Flat mood, poor sleep and no interest in much of anything | Depression or exhaustion rather than a sexual problem | Say the mood part out loud in the appointment |
Depression deserves its own line here, because it lowers desire directly and because its treatment can lower desire further. That is not an argument against treatment. It is an argument for telling your doctor which of the two is bothering you more, so the drug can be chosen accordingly.
Persistent tiredness with no interest in sex is often one problem rather than two, and our guide to why you might be always tired works through the causes that show up on blood tests.
What to bring to the appointment
Ten minutes goes fast. Arrive with the evidence rather than the sentence.
- When it started, and whether it faded or dropped
- Every medicine and supplement, including anything started in the past year
- Whether morning erections still happen
- Alcohol in a typical week, and your usual hours of sleep
- Mood, stress and what is happening in the relationship
- Other symptoms: weight change, thirst, feeling cold, breast tenderness
A low sex drive is rarely the whole story and it is rarely nothing. Treated as a symptom with a short list of suspects, it is one of the more solvable problems in men's health. Treated as a personal failing, it stays exactly where it is.
Frequently asked questions
What causes a low sex drive in men?
The NHS lists relationship problems, stress, anxiety or depression, sexual problems such as erectile dysfunction, falling hormone levels with age, certain medicines including antidepressants and blood pressure drugs, and heavy drinking. Long-term conditions such as heart disease, diabetes and an underactive thyroid also lower desire.
Can antidepressants lower sex drive?
Frequently. A meta-analysis of trial data found rates of treatment-emergent sexual dysfunction ranging from 25.8% to 80.3% depending on the drug, with sertraline, venlafaxine, citalopram and paroxetine at the high end and bupropion, mirtazapine and a few others no different from placebo. Never stop a prescribed antidepressant on your own; ask about switching.
Does low sex drive mean low testosterone?
Not on its own, but desire is one of the symptoms most worth testing for. Reduced libido alongside fewer morning erections is the pattern that points at hormones. In the largest trial of testosterone therapy in older men with low levels, sexual function including desire improved, while energy did not.
When should I see a doctor about low libido?
If it has lasted a few months, if it is affecting your relationship, if it started after a new prescription, or if it comes with erection problems, low mood or unexplained tiredness. Bring the timeline and your full medication list to the appointment.
References
- Low sex drive (loss of libido) · NHS
- Treatment-emergent sexual dysfunction related to antidepressants: a meta-analysis · Journal of Clinical Psychopharmacology, 2009
- Sexual dysfunction associated with selective serotonin reuptake inhibitors in adults with depression: a systematic review and meta-analysis · European Journal of Clinical Pharmacology, 2026
- Effects of Testosterone Treatment in Older Men · New England Journal of Medicine, 2016
- Effect of 1 week of sleep restriction on testosterone levels in young healthy men · JAMA, 2011
- Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis · European Journal of Endocrinology, 2013
- Low Testosterone (Male Hypogonadism) · Cleveland Clinic
