Male night sweats are most commonly caused by low testosterone, medications, sleep apnea, or lifestyle factors like alcohol use. Less often, they signal an underlying condition such as an overactive thyroid or infection. Most causes are treatable once identified, but persistent drenching sweats, especially alongside unexplained weight loss or fever, deserve prompt medical attention.
Low Testosterone and Thermoregulation
Testosterone levels naturally decline with age, dropping roughly 1% per year after age 30. When levels fall low enough, the thermal control center in the hypothalamus can malfunction. The nervous system sends signals that widen blood vessels in the skin, producing a sudden flush of warmth. The body then overcorrects by triggering a cold, clammy sweat. This is the same basic mechanism behind hot flashes in women during menopause, and it can happen to men at any hour, including during sleep.
Testosterone-related night sweats are especially common in men undergoing hormone-suppression therapy for prostate cancer, but they also occur in men whose levels drop naturally or due to conditions affecting the testes or pituitary gland. If low testosterone is the cause, you’ll likely notice other symptoms too: reduced sex drive, fatigue, difficulty concentrating, or loss of muscle mass.
Medications That Trigger Sweating
Antidepressants are among the most common medication culprits. SSRIs and SNRIs cause excessive sweating in roughly 7% to 19% of people who take them. This includes widely prescribed drugs like sertraline (Zoloft), fluoxetine (Prozac), paroxetine (Paxil), venlafaxine (Effexor), and duloxetine (Cymbalta). The sweating often occurs at night and can start weeks or months into treatment.
Other medications linked to night sweats include blood pressure drugs, hormone therapies, diabetes medications (which can cause overnight blood sugar drops), and over-the-counter fever reducers like aspirin or acetaminophen. If your night sweats started around the same time as a new prescription, that timing is worth mentioning to your doctor.
Sleep Apnea
About 30% of people with obstructive sleep apnea report night sweats. The connection comes down to what happens each time your airway closes during sleep: your body partially wakes, your muscles tense, and your sympathetic nervous system fires up. That repeated fight-or-flight activation throughout the night raises your core temperature and drives sweating. Studies comparing people with and without sleep apnea found night sweat prevalence of roughly 19% versus 12%.
If your night sweats come with loud snoring, gasping awake, morning headaches, or daytime exhaustion, sleep apnea is a strong possibility. Treating the apnea, typically with a CPAP machine or oral appliance, often resolves the sweating.
Alcohol and Diet
Alcohol increases your heart rate and widens blood vessels in the skin, both of which raise skin temperature and trigger perspiration during sleep. This effect is dose-dependent: the more you drink in the evening, the worse the sweating. It doesn’t take heavy drinking to cause it. Even a few drinks close to bedtime can be enough.
For people who are physically dependent on alcohol, sudden withdrawal produces its own version of night sweats, often more severe. Clammy skin and drenching sweats are hallmark withdrawal symptoms. Spicy foods, caffeine, and large meals close to bedtime can also raise core body temperature enough to provoke sweating, though these tend to cause milder episodes.
Thyroid Problems
An overactive thyroid speeds up your entire metabolism. The thyroid’s two main hormones influence every cell in the body, including how you burn fat and carbohydrates and how you regulate body temperature. When the gland produces too much of these hormones, your internal thermostat runs hot. You’ll feel warmer than everyone around you, sweat more easily, and often wake up damp.
Other signs of an overactive thyroid include unexplained weight loss, a rapid or irregular heartbeat, anxiety, trembling hands, and more frequent bowel movements. A simple blood test measuring thyroid-stimulating hormone can confirm or rule this out.
Infections
Certain infections are known for causing drenching night sweats. Tuberculosis is the classic example. Active TB typically develops gradually over weeks, with a persistent cough, chest pain, fever, chills, weight loss, and fatigue alongside the sweating. TB can also affect areas outside the lungs (bones, kidneys, spine), and night sweats remain a prominent symptom regardless of the site.
HIV, endocarditis (an infection of the heart valves), and abscesses can all produce night sweats as well. Infectious causes tend to come with additional symptoms like fever, fatigue, and weight loss, rather than sweating in isolation.
When Night Sweats May Signal Cancer
Night sweats are one of the “B symptoms” associated with lymphoma and certain other cancers. The key distinction is severity. Drenching night sweats that force you to change your clothes or bedding are more concerning than mild dampness. Cancer-related sweats are also typically accompanied by unexplained weight loss (more than 10% of body weight over six months) and recurring fevers.
Night sweats alone, without these other red flags, are rarely caused by cancer. But if all three symptoms are present, or if the sweating is persistent and unexplained after ruling out more common causes, further evaluation is warranted.
How Persistent Night Sweats Are Diagnosed
When a physical exam and medical history don’t point to an obvious cause, doctors typically start with a standard set of blood tests: a complete blood count, thyroid-stimulating hormone level, HIV test, and markers of inflammation like C-reactive protein. Tuberculosis testing and a chest X-ray are also part of the initial workup. If overnight blood sugar drops are suspected, you may be asked to check your glucose during a typical episode.
If these initial tests come back normal, the next steps may include imaging of the chest or abdomen, a sleep study to check for apnea, or more specialized blood work depending on the clinical picture. The goal is to work from the most common and easily tested causes toward rarer ones.
Managing Night Sweats at Home
While you work on identifying the underlying cause, a few adjustments can reduce the frequency and severity of episodes. Keep your bedroom between 60°F and 67°F. Switch to breathable bedding made from cotton, bamboo, or linen rather than synthetic fabrics that trap heat. Moisture-wicking sleepwear helps prevent sweat from pooling against your skin.
Cutting back on alcohol, especially in the three to four hours before bed, makes a noticeable difference for many men. The same goes for spicy food and caffeine in the evening. Staying at a healthy weight also helps, partly because excess body fat insulates heat and partly because obesity is a major risk factor for sleep apnea. These changes won’t fix a hormonal or infectious cause, but they reduce the burden on your body’s cooling system while you pursue a diagnosis.