Several hormones can cause night sweats, but the most common culprit is estrogen. When estrogen levels drop, your brain’s internal thermostat narrows its comfort range, triggering sweating in response to tiny temperature changes that wouldn’t normally bother you. Estrogen isn’t the only hormone involved, though. Thyroid hormones, adrenaline, cortisol, testosterone, and the hormones that regulate blood sugar can all play a role depending on the underlying cause.
Estrogen: The Most Common Trigger
Estrogen is far and away the hormone most frequently responsible for night sweats. Your hypothalamus, the part of the brain that works as your body’s thermostat, has estrogen receptors on it. When estrogen levels fall, the hypothalamus becomes hypersensitive to even minor shifts in body temperature.
Normally, your thermostat tolerates a range of about 0.4°C before it kicks off a cooling response like sweating. When estrogen drops, that range narrows dramatically. A fluctuation that would have gone unnoticed before now pushes past the threshold, and your body launches into a full heat-dumping response: blood vessels in the skin dilate, sweat glands activate, and you wake up drenched. This is the same mechanism behind daytime hot flashes.
This process is most familiar in perimenopause and menopause, where roughly 24% of women across all age groups report hot flashes and sweating. Prevalence climbs starting around age 40, peaks near age 52, and then gradually declines. But estrogen-driven night sweats also happen after childbirth. Estrogen and progesterone plummet once the placenta is delivered, and postpartum night sweats tend to be worst during the first two weeks, usually resolving within six weeks. Women who breastfeed often sweat longer because prolactin, the hormone that drives milk production, keeps estrogen suppressed.
Thyroid Hormones and Metabolic Heat
Your thyroid gland produces two hormones, T3 and T4, that influence how every cell in your body uses energy. They help set your metabolic rate, control how fast you burn fats and carbohydrates, and directly regulate body temperature. When the thyroid becomes overactive, a condition called hyperthyroidism, it floods the bloodstream with excess T3 and T4. The result is a body running too hot. Your basal metabolic rate climbs, core temperature rises, and sweating becomes the body’s constant attempt to cool down.
Unlike estrogen-related night sweats, thyroid-driven sweating usually happens around the clock, not only at night. You’ll typically notice increased heat sensitivity during the day as well, along with a rapid heartbeat, unintentional weight loss, and anxiety. Night sweats in this case are really just part of a broader pattern of overheating.
Adrenaline and Noradrenaline
Adrenaline (epinephrine) and noradrenaline (norepinephrine) are your fight-or-flight hormones. They raise heart rate, spike blood pressure, and trigger sweating. In most people, these hormones stay quiet during sleep. But two situations can change that.
The first is a rare adrenal tumor called a pheochromocytoma. These tumors sit inside the adrenal gland and release surges of adrenaline and noradrenaline unpredictably. The classic symptoms are sudden episodes of high blood pressure, pounding headache, heavy sweating, and rapid heartbeat. These episodes come and go, can happen at any time of day or night, and often feel like a panic attack. Pheochromocytomas are uncommon, but they’re an important cause to rule out when night sweats come with those additional symptoms.
The second situation is nocturnal hypoglycemia, where blood sugar drops too low during sleep. Adrenaline is the body’s primary hormonal defense against low blood sugar. When glucose falls, your adrenal glands release a burst of epinephrine to mobilize stored sugar. That adrenaline surge also triggers sweating, a racing heart, and sometimes trembling. This is especially relevant for people with type 1 diabetes. During sleep, the epinephrine response to low blood sugar is significantly blunted in people with diabetes compared to those without it, which means episodes can go unrecognized and become recurrent.
Testosterone in Men
Low testosterone causes night sweats in men through a mechanism that mirrors what happens with low estrogen in women. Testosterone influences the hypothalamic thermostat, and when levels fall significantly, the result is vasomotor instability: hot flashes, flushing, and night sweats. Hot flashes are listed among the hallmark symptoms of male hypogonadism, alongside low energy, reduced muscle mass, and changes in sexual function.
This is most commonly seen in men receiving hormone-suppression therapy for prostate cancer, but it also occurs in age-related testosterone decline and other causes of hypogonadism. The sweating pattern is similar to menopausal night sweats: sudden onset of heat, visible flushing, and drenching perspiration that can wake you from sleep.
Cortisol and the Stress Response
Cortisol is produced by the adrenal glands in response to stress, following a chain of signals from the brain called the HPA axis. Its relationship with night sweats is more complex and somewhat circular. Research on postmenopausal women found that cortisol levels rise during a hot flash, with the stress hormone ACTH peaking about five minutes after a flash begins and cortisol following about ten minutes after that. This suggests the hot flash itself triggers a stress response, which may then intensify the sweating.
There’s also evidence that chronically elevated cortisol makes vasomotor symptoms worse. In a large study of women going through the menopausal transition, those with higher morning urinary cortisol had significantly more severe hot flashes and cold sweats. Women with higher cortisol were also more likely to fall into the cluster of symptoms that included intense hot flashes and frequent nighttime awakening. Cortisol normally follows a daily rhythm, peaking in the morning and dropping to its lowest point around midnight. Disruptions to that rhythm, whether from chronic stress, shift work, or other factors, may lower the threshold for nighttime sweating even when another hormone is the primary driver.
How These Causes Are Identified
Because so many different hormones can be involved, the diagnostic path depends heavily on your other symptoms, age, and medical history. A standard initial workup for unexplained night sweats typically includes a complete blood count, thyroid-stimulating hormone level, and inflammatory markers to help sort hormonal causes from infections or other conditions.
For women in their 40s or 50s, the pattern alone is often enough to point toward estrogen. Night sweats that come with a sudden sensation of heat rising through the chest and face, last a few minutes, and happen alongside irregular periods are classic perimenopausal vasomotor symptoms. In younger women, a recent pregnancy or breastfeeding history explains most cases.
For men, testosterone levels can be measured with a simple blood draw, usually taken in the morning when levels are highest. When night sweats come with episodes of high blood pressure and a pounding heart, testing for excess adrenaline (through urine or blood catecholamine levels) rules out a pheochromocytoma. And for anyone on insulin or medications that lower blood sugar, tracking overnight glucose with a continuous monitor can reveal whether hypoglycemia is the trigger.
In most cases, night sweats resolve once the underlying hormonal imbalance is identified and addressed. The timeline varies: postpartum sweats clear within weeks, thyroid-related sweating responds relatively quickly to treatment, and menopausal night sweats can persist for years but tend to ease over time.