Night sweats in men have a wide range of causes, from something as manageable as alcohol use or medication side effects to conditions that need medical attention like low testosterone or sleep apnea. True night sweats go beyond feeling warm because your bedroom is stuffy. They involve enough sweating to soak through your sheets or sleepwear, and they happen repeatedly.
Low Testosterone and Hot Flashes
Most people associate hot flashes with menopause, but men experience them too. Low testosterone is the primary driver, and it works through the same basic mechanism. The brain’s temperature control center, located in the hypothalamus, becomes more sensitive when sex hormone levels drop. It misreads normal body temperature as too high and sends signals to cool you down. Blood vessels near the skin’s surface widen rapidly, producing a flush of heat. Your body then overcorrects by triggering a cold, clammy sweat.
Testosterone levels naturally decline with age, dropping roughly 1% per year after age 30. But night sweats from low testosterone are more common in men receiving androgen deprivation therapy for prostate cancer, where hormone levels are reduced dramatically and quickly. If your night sweats come with other signs of low testosterone (fatigue, reduced sex drive, difficulty concentrating, or loss of muscle mass), a simple blood test can confirm whether your levels are low.
Sleep Apnea
Obstructive sleep apnea is one of the most underrecognized causes of night sweats in men, and it’s worth considering because many men have it without knowing. About 31% of people with obstructive sleep apnea report frequent night sweats (three or more times a week), compared to roughly 11% in the general population. When your airway collapses during sleep, your oxygen levels drop and your nervous system kicks into a stress response, releasing adrenaline and raising your heart rate. That fight-or-flight activation generates heat and sweating.
The clue that sleep apnea might be behind your night sweats is what else is happening at night. If your partner notices loud snoring, gasping, or pauses in your breathing, or if you wake up with a dry mouth and feel exhausted despite a full night of sleep, apnea is a strong possibility. Treating the apnea (typically with a CPAP machine) often resolves the sweating.
Medications
Several common medications cause night sweats as a side effect, and antidepressants are among the most frequent offenders. In one primary care study, people taking SSRIs (a widely prescribed class of antidepressants) were about three times more likely to report night sweats than those not taking them. Other medications linked to night sweats include drugs for diabetes that can cause blood sugar to drop overnight, fever reducers like aspirin or acetaminophen (which affect the body’s thermostat), and some blood pressure medications.
If your night sweats started around the same time you began a new medication or changed your dose, that timing is a strong signal. Don’t stop a prescription on your own, but it’s worth raising the connection with whoever prescribed it. A dose adjustment or switch to a different drug in the same class often helps.
Alcohol
Alcohol is a straightforward cause that many men overlook. Drinking raises your core body temperature by dilating blood vessels near the skin, which increases blood flow to the surface. Even a few drinks in the evening can be enough to trigger sweating later that night as your body tries to shed the extra heat.
The effect is more intense during withdrawal. When someone who drinks heavily cuts back or stops, the central nervous system, which alcohol has been suppressing, rebounds into overdrive. Temperature regulation, heart rate, and blood pressure all become harder for the body to control. Night sweats during withdrawal can be severe and are part of a broader set of symptoms that may need medical support.
Overactive Thyroid
The thyroid gland controls your metabolic rate, essentially how fast your body burns energy. When it produces too much hormone, everything speeds up. Your heart beats faster, you lose weight without trying, you feel anxious or jittery, and your body generates more heat than it can comfortably manage. Increased sensitivity to heat and excessive sweating, including at night, are hallmark symptoms of hyperthyroidism.
Because thyroid hormones affect every cell in the body, the symptoms tend to show up across multiple systems at once. If night sweats come alongside a rapid or irregular heartbeat, unexplained weight loss, trembling hands, or frequent bowel movements, a thyroid panel (a routine blood test) can confirm whether your thyroid is overactive.
Infections
Night sweats are a classic symptom of several infections. Tuberculosis is the textbook example, producing drenching sweats along with a persistent cough, fever, and weight loss. Bacterial infections of the heart valves (endocarditis) and bone infections (osteomyelitis) can also cause sweating at night. HIV, particularly in its early acute phase, often triggers night sweats as part of a flu-like illness that appears weeks after exposure.
Infections severe enough to cause night sweats almost always come with other symptoms: fever, chills, fatigue, or pain. If sweating at night is your only symptom, infection is less likely to be the explanation, but it’s not something to rule out on your own.
Acid Reflux
This one surprises most people. Gastroesophageal reflux that worsens at night (because lying flat lets stomach acid travel more easily into the esophagus) can trigger your body’s stress response. That adrenaline release generates heat and sweating. You might not even register the reflux as heartburn if it’s mild, making the connection easy to miss. If your night sweats tend to be worse after large or late meals, reflux is worth considering.
Lymphoma and Other Cancers
Night sweats are one of the “B symptoms” associated with lymphoma, a cancer of the lymphatic system. The sweats associated with lymphoma are typically described as drenching, enough to require changing your sheets or clothes. They often appear alongside unexplained weight loss (more than 10% of body weight over six months), persistent fevers, and swollen lymph nodes in the neck, armpits, or groin that are usually painless.
Other cancers can cause night sweats too, including leukemia and some solid tumors. Cancer is not the most common explanation for night sweats, but it’s the one that matters most to catch early. The combination of drenching sweats, weight loss, and fevers is what distinguishes cancer-related sweats from more benign causes.
When Night Sweats Need Attention
Occasional night sweats after a hot day, a spicy meal, or a few drinks are normal and don’t require investigation. The pattern that warrants a visit to your doctor is night sweats that happen regularly, wake you up, or come with other symptoms. Specific warning signs include losing weight without trying, running fevers or feeling feverish and chilled, a persistent cough, or swollen glands. Night sweats that have been going on for more than two to three weeks without an obvious explanation (like a warm bedroom or recent illness) are also worth getting checked.
Your doctor will likely start with blood work to check hormone levels, thyroid function, blood sugar, and markers of infection or inflammation. If sleep apnea is suspected, a sleep study is the standard next step. In most cases, the cause turns out to be something treatable, and the sweating resolves once the underlying issue is addressed.