Low libido in men: how it differs from ED, and common causes

The short version: low libido and erectile dysfunction (ED) are two different problems that often get lumped together. Low libido, which the NHS calls low sex drive, is about how much you want sex. ED is about whether your body can get or keep an erection firm enough for sex. A man can have one, the other or both, and erection trouble can itself lower sex drive. The NHS lists stress, depression, relationship problems, certain medicines, heavy drinking and long-term conditions among the main causes of a low sex drive (NHS, Low sex drive). Low testosterone is on the list of possibilities too, but it takes repeat blood tests, not a symptom checklist, to show it.

Is it ED or low desire?

ED is a problem with erections, and low libido is a problem with wanting sex in the first place. The NIH describes ED symptoms as getting an erection sometimes but not every time you want sex, getting one that does not last long enough for sex, or being unable to get one at all (NIDDK, Symptoms & Causes of ED). Low libido is different: the interest itself has faded, whether or not erections still work. A useful first question to ask yourself is which came first, the lack of interest or the trouble with erections.

The two are tangled, though. The NHS names erectile dysfunction itself as one of the main causes of a low sex drive (NHS), so a man who keeps running into erection trouble may start to want sex less. That is why clinicians ask about both. When a health care professional assesses ED, the NIH says they review climax, ejaculation, erection and sexual desire, along with mental health and the relationship (NIDDK, Diagnosis of ED).

Sources: NIDDK, Symptoms & Causes; NIDDK, Diagnosis; NHS, Low sex drive. For the erection side, our guide to ED symptoms walks through what counts and what does not.

What are the signs of low libido in males?

The main sign is a drop in your interest in sex compared with what is normal for you, and it is worth raising when it worries you. The NHS’s advice is simply to see a GP if you are worried about your low sex drive, or if you think a medicine you take may be affecting it (NHS).

Context is part of the picture. A dip during a stressful stretch, a bout of illness or a hard patch in a relationship is different from a steady change with no clear reason. Noting when it started, what else changed around then and whether erections have changed too gives a clinician much more to work with.

What causes low libido in men?

Low libido has many possible causes, and there may be more than one at once. These are the causes the NHS names that apply to men, with what each source says about them.

Sources: NHS, Low sex drive; NIDDK, Prolactinoma.

Mood deserves a special mention, because depression and the medicines that treat it can both lower desire. Our page on depression, antidepressants and ED covers that two-way link. Another medicine whose label lists libido effects is finasteride: in three 12-month hair-loss trials described on its label, decreased libido judged possibly, probably or definitely drug-related was reported by 1.8% of men on finasteride and 1.3% on placebo, and the label also lists post-marketing reports of libido problems that continued after stopping (PROPECIA label, DailyMed). Our finasteride and ED page goes through those figures and their limits.

How is testosterone checked?

Testosterone is checked with blood tests, taken in the morning while fasting and repeated before anyone calls it low. The Endocrine Society guideline recommends measuring fasting morning total testosterone with an accurate assay as the first test and confirming it by repeating that measurement; when the result is near the lower limit of normal, or a condition changes the protein that carries testosterone in the blood, it recommends measuring free testosterone too (Bhasin et al., Endocrine Society guideline, 2018). If a deficiency is confirmed, the guideline recommends further tests to find out why.

A low number alone is not the diagnosis. The guideline says hypogonadism should be diagnosed only in men who have both symptoms and signs of testosterone deficiency and “unequivocally and consistently low” levels (Bhasin et al., 2018). The American Urological Association (AUA) makes the same point, and adds a caution that matters for low libido: the symptoms linked to low testosterone are “very non-specific” and can come from other conditions, such as chronic fatigue, chronic stress or a depressed state (AUA, Testosterone Deficiency Guideline). The AUA also notes that testosterone testing and prescriptions have nearly tripled in recent years, with many men using testosterone without a clear reason.

For how often low testosterone turns out to be behind erection problems, see can low testosterone cause ED?, and for other hormone causes, hormones and ED.

Does testosterone treatment raise desire?

In older men with confirmed low testosterone and low libido, a large trial found it can help desire and sexual activity. The Sexual Function Trial of the Testosterone Trials enrolled 470 men aged 65 and older with low libido and average testosterone below 275 ng/dL, and gave them testosterone gel or placebo for a year. Testosterone improved 10 of 12 measures of sexual activity compared with placebo, and bigger rises in testosterone (and estradiol) went with bigger improvements in sexual activity and desire, but not in erectile function (Cunningham et al., J Clin Endocrinol Metab, 2016).

Those results come from older men with clearly low levels, so they do not show that testosterone raises desire in men whose levels are normal. The Endocrine Society guideline also lists situations where testosterone should not be started, including men planning to have children soon, and men with breast or prostate cancer or certain heart, blood and sleep conditions (Bhasin et al., 2018). Whether it fits is a decision for a clinician after testing.

Do ED pills raise desire?

Not on their own. ED pills such as sildenafil are approved to treat erectile dysfunction, not low desire. The Viagra label states that sildenafil “at recommended doses has no effect in the absence of sexual stimulation” (VIAGRA prescribing information, DailyMed). In other words, the desire and arousal have to be there first; the medicine helps the blood-flow step that follows. Our explainer on how ED medications work walks through that chain.

That makes the ED-or-desire question practical. If the main problem is erections and desire is intact, ED treatment targets the right thing. If the main problem is that the interest has gone, an ED pill does not address it, and the cause of the low desire is what needs looking at. Where trouble with erections has worn desire down, the NHS notes that treating the sexual problem is one route (NHS).

Low desire is also a separate thing from ejaculation problems. If the concern is finishing too soon rather than wanting sex less, see our page on premature ejaculation.

When should you talk to a clinician about low libido?

Talk to a clinician if a low sex drive worries you or if you think a medicine is affecting it. Those are the reasons the NHS gives for seeing a GP (NHS). Treatment depends on the cause, so the visit is mostly about finding it: a talk about mood, stress, the relationship, alcohol and every medicine you take, and possibly blood tests, which for ED can include thyroid tests (NIDDK, Diagnosis) and, if hormones are in question, repeat morning testosterone (Bhasin et al., 2018).

It helps to go in knowing the answers to a few questions: when the change started, whether desire or erections changed first, whether anything new began around then, such as a medicine, a stressful event or a health problem, and how much you drink. None of this is a self-diagnosis; it is what lets a clinician sort the likely causes quickly.

Sources

• NHS. Low sex drive (loss of libido). Reviewed May 2026.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Symptoms & Causes of Erectile Dysfunction and Diagnosis of Erectile Dysfunction. Reviewed October 2024.
• NIDDK. Prolactinoma. Reviewed September 2019.
• American Urological Association. Evaluation and Management of Testosterone Deficiency. Published 2018, validity confirmed 2024.
• Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab, 2018.
• Cunningham GR, et al. Testosterone Treatment and Sexual Function in Older Men With Low Testosterone Levels. J Clin Endocrinol Metab, 2016.
• PROPECIA (finasteride) prescribing information. DailyMed.
• VIAGRA (sildenafil citrate) prescribing information. DailyMed.