Hot flashes in men are most commonly caused by a significant drop in testosterone, whether from medical treatment, natural decline, or an underlying health condition. While testosterone levels do decrease by about 1% per year after age 40, most men retain enough to avoid hot flashes entirely. The symptom typically shows up when testosterone falls sharply rather than gradually, which is why men undergoing prostate cancer treatment are far more affected than men experiencing normal aging.
How Testosterone Triggers Hot Flashes
Your brain has a thermoregulatory center that acts like an internal thermostat, keeping your body temperature within a narrow comfort zone. Testosterone helps maintain that zone. When testosterone drops suddenly or significantly, the comfort zone narrows, meaning even small fluctuations in body temperature can trigger a cooling response: blood vessels near the skin dilate, you flush, your heart rate increases, and you sweat. That’s a hot flash.
The sensation typically involves a wave of heat spreading across the chest, neck, and face, often followed by sweating and sometimes chills as your body overcorrects. Episodes can last anywhere from a few seconds to several minutes, and some men experience them multiple times a day while others get them only occasionally.
Prostate Cancer Treatment Is the Leading Cause
The single most common reason men develop hot flashes is androgen deprivation therapy (ADT) for prostate cancer. This treatment works by dramatically lowering testosterone to slow tumor growth, but the steep hormonal drop produces hot flashes in up to 80% of men who receive it. For many, the flashes begin within weeks of starting treatment and persist for months or even years. They can be severe enough to disrupt sleep, cause anxiety, and significantly affect quality of life.
Surgical removal of the testicles, another treatment for advanced prostate cancer, produces the same effect for the same reason: a rapid, near-total loss of testosterone.
Other Hormonal Causes
Outside of cancer treatment, several conditions can lower testosterone enough to trigger hot flashes. Hypogonadism, where the testes don’t produce adequate hormones, is the most direct. This can result from genetic conditions, injury, infection, or problems with the pituitary gland that controls hormone production.
Thyroid disorders can also play a role. An overactive thyroid raises your metabolic rate and body temperature, producing flushing and sweating that closely mimics hot flashes. Diabetes and metabolic syndrome have been linked to hormonal imbalances that contribute as well. In these cases, the hot flashes are a secondary symptom of a broader condition rather than a standalone problem.
Medications That Cause Flushing
Several common medications can trigger hot flashes or excessive sweating in men, even without any underlying hormonal issue. Antidepressants, particularly SSRIs like fluoxetine, sertraline, and escitalopram, are well-known culprits. Opioid painkillers such as oxycodone and morphine stimulate the release of histamine from immune cells, leading to flushing and sudden sweating. Corticosteroids like prednisone, ADHD stimulant medications, and certain diabetes drugs can all produce similar effects.
If your hot flashes started around the same time as a new medication, that connection is worth investigating. The timing is often the clearest clue.
Rare but Serious Conditions to Rule Out
In some cases, flushing and sweating signal something more than a hormonal shift. Several uncommon conditions produce symptoms that look like hot flashes but have very different causes.
- Pheochromocytoma: A tumor of the adrenal gland that releases surges of stress hormones. The hallmark is episodes of flushing paired with high blood pressure, rapid heartbeat, and headaches. About 60% of people with this tumor have sustained high blood pressure with dramatic spikes.
- Carcinoid syndrome: Caused by tumors (usually in the gut) that release excess serotonin and other chemicals into the bloodstream. Flushing tends to come with diarrhea and wheezing.
- Mastocytosis: A condition where too many immune cells accumulate in the skin or organs, releasing histamine that causes flushing, itching, and sometimes anaphylaxis-like reactions.
These conditions are rare, but they’re the reason persistent, unexplained flushing warrants blood and urine tests rather than assumptions. A doctor can check hormone levels alongside markers for these other conditions to narrow down the cause.
Everyday Triggers That Make Them Worse
If you’re already prone to hot flashes, certain foods and habits can increase their frequency and intensity. Caffeine is one of the most common aggravators. It stimulates the nervous system in ways that can set off or worsen episodes, and it creates a frustrating cycle: hot flashes disrupt your sleep, you drink more coffee to compensate, and the caffeine triggers more hot flashes.
Alcohol, especially more than one drink a day, increases both the frequency and intensity of episodes. Spicy foods raise your core temperature enough to push past that narrowed comfort zone. Even hot beverages, regardless of their ingredients, can be enough to trigger an episode. Ultra-processed foods, including fast food, sugary drinks, and fried foods, tend to raise blood pressure, which can also fuel hot flashes.
Stress and warm environments are additional triggers. Layered clothing, hot showers, and heated rooms can all tip the balance.
How Hot Flashes Are Managed
Treatment depends entirely on the cause. When low testosterone is the driver and there’s no medical reason to keep levels suppressed, hormone replacement can effectively eliminate hot flashes. For men on androgen deprivation therapy for prostate cancer, that option isn’t available since restoring testosterone would defeat the purpose of treatment.
For those men, non-hormonal medications can help. In clinical trials of men experiencing at least 14 hot flashes per week from cancer treatment, the highest dose of gabapentin tested reduced hot flash frequency to about 55% of baseline levels (compared to 71% with a placebo). Lower doses showed little benefit beyond placebo. Certain antidepressants that affect serotonin and norepinephrine signaling are also used, since these brain chemicals play a direct role in temperature regulation.
Lifestyle adjustments make a meaningful difference alongside any medical treatment. Keeping your environment cool, dressing in layers you can remove quickly, cutting back on caffeine and alcohol, and avoiding spicy foods won’t eliminate hot flashes, but they reduce how often episodes happen and how intense they feel. Regular exercise and stress management techniques also help stabilize the body’s temperature regulation over time.