Night sweats in men most often stem from medications, sleep disorders, infections, hormonal shifts, or low blood sugar, though sometimes no clear cause is found. Unlike simply feeling warm under heavy blankets, true night sweats involve enough sweating to soak through your clothes or sheets regardless of bedroom temperature. The list of possible triggers is long, but a handful of causes account for the vast majority of cases.
Medications, Especially Antidepressants
One of the most common and overlooked causes is medication. Antidepressant-induced excessive sweating affects up to 22% of people taking these drugs, and it spans every major class: SSRIs, SNRIs, and tricyclic antidepressants. Some of these medications overstimulate receptors involved in your body’s “fight or flight” system, which activates sweat glands. Others interfere with the brain’s temperature-regulation center, triggering sweating even when your body doesn’t need to cool down.
If you started or changed an antidepressant and then began waking up drenched, the timing is likely not coincidental. Other medications linked to night sweats include fever-reducing drugs like aspirin and acetaminophen (which can paradoxically cause rebound sweating), blood pressure medications, and hormone therapies. Opioids and drugs used to treat diabetes can also be culprits.
Obstructive Sleep Apnea
Sleep apnea is a surprisingly common trigger that many men don’t connect to sweating. In a study of over 800 newly diagnosed sleep apnea patients, 31% reported frequent night sweats (three or more times a week), compared to just 11% in the general population. When your airway repeatedly collapses during sleep, your body releases stress hormones to jolt you awake enough to breathe again. That adrenaline surge raises your heart rate and activates your sweat glands.
If your night sweats come alongside loud snoring, gasping during sleep, or daytime exhaustion, sleep apnea is worth investigating. Many men with sleep apnea find their sweating resolves once they start treatment with a continuous positive airway pressure (CPAP) device.
Low Testosterone
Testosterone levels naturally decline with age, typically starting in a man’s 30s or 40s. When levels drop low enough, the body’s internal thermostat can malfunction in much the same way it does during menopause in women. The result is sudden heat surges and sweating, often concentrated at night. This is sometimes called “andropause” or male hypogonadism.
Low testosterone rarely causes night sweats in isolation. You’d typically also notice reduced sex drive, fatigue, difficulty concentrating, or mood changes. A simple morning blood test measuring total testosterone can confirm or rule this out. Levels are highest in the early morning, so timing the test matters.
Low Blood Sugar During Sleep
For men with diabetes, particularly those using insulin or certain oral medications, blood sugar can drop dangerously low overnight. When this happens, your body floods itself with stress hormones to raise glucose levels, and one of the most visible signs is waking up in damp or soaked clothes. You might also notice a headache, shakiness, or feeling unrested in the morning.
Nocturnal hypoglycemia can happen without waking you, so you may not realize it’s occurring. Checking blood sugar before bed and again in the morning can reveal the pattern. Adjusting the timing of your evening meal, your medication dose, or having a small bedtime snack with protein and complex carbohydrates can help stabilize overnight levels.
Infections
Night sweats are a hallmark symptom of several infections. Tuberculosis is the classic example. The CDC lists night sweats alongside fever, weight loss, fatigue, and coughing up blood as general symptoms of active TB disease. HIV is another infection strongly associated with drenching night sweats, particularly when the immune system is significantly compromised.
Bacterial infections of the heart valves (endocarditis) and abscesses can also produce persistent sweating at night. In most infectious causes, you’ll have other symptoms too: fever, unintentional weight loss, or prolonged fatigue. Isolated night sweats without any other signs are less likely to point to a serious infection, but prolonged episodes lasting more than a few weeks deserve medical attention.
Overactive Thyroid and Other Hormonal Causes
An overactive thyroid gland revs up your entire metabolism, generating excess heat that your body tries to dump through sweating. You’d typically also experience a rapid heartbeat, unexplained weight loss, anxiety, and trembling hands. A thyroid-stimulating hormone (TSH) blood test can quickly identify this.
Rarer hormonal causes include tumors of the adrenal glands (pheochromocytoma), which release bursts of adrenaline that cause dramatic episodes of sweating, rapid heart rate, and high blood pressure. Carcinoid tumors, which release hormones into the bloodstream, can trigger flushing and sweating as well. These are uncommon but worth mentioning because they’re treatable once identified.
Lymphoma and Other Cancers
Night sweats are one of three “B symptoms” used to stage certain cancers, particularly Hodgkin lymphoma and some non-Hodgkin lymphomas. These cancer-related night sweats have a specific character: they’re drenching, meaning you need to change your bedclothes. They’re accompanied by unexplained fever above 100.4°F and unexplained weight loss of more than 10% of your body weight within six months.
It’s important to keep perspective here. Cancer is one of the least common causes of night sweats, but it’s the one people worry about most. Night sweats alone, without fever and weight loss, are rarely the first sign of lymphoma. That said, persistent drenching sweats that don’t respond to simple fixes like adjusting your bedroom temperature or changing your bedding are worth bringing to a doctor’s attention.
Alcohol and Lifestyle Factors
Alcohol causes night sweats through two mechanisms. First, it dilates blood vessels near the skin, increasing heat loss and triggering compensatory sweating. Second, as your body metabolizes alcohol overnight, the withdrawal-like rebound effect stimulates your nervous system, producing sweating, a raised heart rate, and restless sleep. Even moderate drinking in the evening can be enough to trigger this in some men.
Spicy food, caffeine close to bedtime, and exercising late in the evening can all raise core body temperature enough to cause sweating during sleep. These are the easiest causes to test: eliminate them one at a time and see if your symptoms improve within a week or two.
What Doctors Test For
If lifestyle changes and a review of your medications don’t solve the problem, doctors follow a fairly standard workup. The American Academy of Family Physicians recommends starting with a complete blood count, a TB test, thyroid-stimulating hormone, an HIV test, a marker of inflammation called C-reactive protein, and a chest X-ray. For men specifically, an early-morning total testosterone level is part of the evaluation.
Further testing depends on what your history suggests. If you have episodes of dramatic flushing and high blood pressure, a 24-hour urine collection can check for excess adrenaline-like hormones. If there’s concern about a heart valve infection, blood cultures and an echocardiogram come next. The goal is to move from the most common and easily treatable causes toward the rarer ones, ruling them out systematically.
Managing Night Sweats While Seeking Answers
While you and your doctor work through potential causes, a few practical steps can reduce how disruptive the sweating is. Keep your bedroom cool (65 to 68°F is ideal for most people) and use moisture-wicking sheets and sleepwear. Sleep on a towel layered over your sheet so you can swap it out without remaking the entire bed.
For men whose sweating persists after underlying causes have been addressed, or when no cause is found (called idiopathic night sweats), prescription-strength antiperspirants containing aluminum chloride can help. You apply them to dry skin before bed and wash them off in the morning. Nerve-blocking oral medications that reduce sweat gland activity are another option, though they can cause dry mouth and blurred vision. These treatments target the sweating itself rather than the root cause, so they work best as a complement to, not a replacement for, proper diagnosis.