Increased sweating can come from dozens of causes, ranging from a new medication or dietary habit to a hormonal shift or underlying health condition. The key to figuring out what’s behind yours is paying attention to the pattern: where on your body it happens, whether it’s symmetrical or one-sided, whether it occurs at night, and when it started. These details point toward very different explanations.
Two Types of Excessive Sweating
Doctors split excessive sweating into two categories, and the distinction matters because it changes what you should do about it.
Primary hyperhidrosis is excessive sweating with no underlying medical cause. It typically starts before age 25, runs in families, and targets specific high-sweat-gland areas: your palms, soles of your feet, underarms, or face. It’s bilateral, meaning both hands or both underarms sweat equally. It doesn’t happen during sleep. If this sounds like your experience, you’ve likely dealt with it for years, and the real question is whether it’s gotten worse or you’re just more bothered by it.
Secondary hyperhidrosis is sweating caused by something else, whether a medication, a medical condition, or a hormonal change. It tends to start after age 25 and looks different clinically. In one study comparing the two types, secondary hyperhidrosis was 18 times more likely to be generalized (all over the body rather than in specific spots), 51 times more likely to be asymmetric or one-sided, and 23 times more likely to include night sweats. More than half of secondary cases began after age 25, compared to just 12% of primary cases. If your sweating is new, widespread, or wakes you up at night, a secondary cause is far more likely.
Medications That Increase Sweating
One of the most common and most overlooked reasons for a sudden uptick in sweating is a medication you recently started or changed doses on. Several major drug classes are known to cause it:
- Antidepressants (SSRIs and SNRIs): Drugs like citalopram, escitalopram, fluoxetine, paroxetine, and venlafaxine increase sweating by affecting serotonin signaling in the brain’s temperature control center.
- Opioid pain medications: Codeine, morphine, oxycodone, tramadol, and fentanyl trigger histamine release, which activates sweat glands.
- Tricyclic antidepressants: Older antidepressants like amitriptyline and imipramine stimulate receptors that ramp up sweating.
- Thyroid medications: Levothyroxine, if dosed too high, can push your body into a mildly overactive thyroid state that increases heat production and sweating.
- Steroids: Prednisone, dexamethasone, and hydrocortisone influence hormone pathways that affect temperature regulation.
If you started or adjusted any medication in the weeks before your sweating increased, that’s worth discussing with your prescriber. In many cases, a dose adjustment or switch to a related drug can fix it.
Hormonal Changes and Menopause
Estrogen plays a direct role in how your brain regulates body temperature. When estrogen levels drop during perimenopause and menopause, the hypothalamus (your brain’s internal thermostat) becomes hypersensitive to tiny changes in core body temperature. A rise of just a fraction of a degree that your body would previously have ignored now triggers a full cooling response: blood vessels dilate, your heart rate increases, and your sweat glands activate. That’s the classic hot flash.
The mechanism involves specific brain chemicals called kisspeptin and neurokinin B, which become overactive when estrogen declines. These same chemicals influence both reproductive hormones and temperature regulation, which is why the two systems are so tightly linked. Hot flashes and sweating episodes can begin years before periods actually stop, so you don’t need to be in full menopause for this to be the cause.
Thyroid disorders work similarly. An overactive thyroid increases your metabolic rate, generating more internal heat and forcing your body to sweat more to compensate. This is one of the more common medical explanations for new-onset sweating and is easy to check with a simple blood test.
Night Sweats Specifically
If your increased sweating is mainly happening at night, the list of potential causes narrows. In an Icelandic study, roughly one-third of people diagnosed with obstructive sleep apnea reported night sweats, a rate three times higher than people without the condition. When those patients were treated with a CPAP machine, the rate of night sweats dropped to about 12%. So if you snore, wake up gasping, or feel unrested despite a full night’s sleep, sleep apnea could be the link.
Night sweats are also a recognized symptom of certain infections (tuberculosis, mononucleosis, endocarditis, HIV) and some cancers, particularly lymphoma and leukemia. These conditions almost always come with other symptoms like unexplained weight loss, persistent fever, or swollen lymph nodes. Isolated night sweats without any other symptoms are far less concerning but still worth mentioning to your doctor if they persist.
It’s also worth noting that some people simply notice sweating more at night because they’re lying still in bed with nothing to distract them. Daytime sweating that you’d barely register while active becomes impossible to ignore when you’re trying to fall asleep.
Food, Drink, and Lifestyle Triggers
Spicy food is a reliable sweat trigger for a straightforward reason. Capsaicin, the compound that makes peppers hot, activates the same heat receptors in your skin and mouth that respond to actual high temperatures. Your nervous system interprets this as overheating and launches its full cooling protocol: blood vessels dilate, body temperature spikes briefly, and sweat glands kick in to evaporate the perceived excess heat. If you’ve recently added more spicy food to your diet, that alone could explain increased sweating around meals.
Caffeine stimulates your central nervous system and can raise your baseline level of sympathetic nervous activity, the “fight or flight” system that also controls sweating. Alcohol, meanwhile, dilates blood vessels and increases skin blood flow, which can trigger sweating both while you’re drinking and during withdrawal the next day. If your coffee, energy drink, or alcohol intake has gone up recently, that’s a simple variable to test by cutting back for a week or two.
Weight gain is another common and underappreciated factor. More body mass means more insulation and more metabolic heat production. Even a gain of 10 to 15 pounds can noticeably increase how much you sweat during activity or in warm environments.
When Increased Sweating Needs Medical Attention
Heavy sweating accompanied by lightheadedness, chest pain, or nausea needs immediate medical attention, as these can signal a cardiac event. Outside of emergencies, the Mayo Clinic flags four situations that warrant a doctor visit: you suddenly begin sweating more than usual with no clear explanation, sweating disrupts your daily routine, you’re getting unexplained night sweats, or the sweating is causing emotional distress or social withdrawal.
A useful self-check is the Hyperhidrosis Disease Severity Scale, a single question clinicians use. Ask yourself: does your sweating never interfere with daily life (mild), sometimes interfere (moderate), frequently interfere (severe), or always interfere (very severe)? If you land in the “frequently” or “always” category, that’s a clear signal to seek help, because effective treatments exist.
Treatment Options That Work
For primary hyperhidrosis focused on specific body areas, the first step is usually a prescription-strength antiperspirant containing aluminum chloride, applied at night to dry skin. These are significantly stronger than anything available over the counter.
If antiperspirants aren’t enough, iontophoresis is an option for hands and feet. You place your hands or feet in a shallow pan of tap water while a low electrical current passes through it, temporarily reducing the ability of sweat glands in that area to produce sweat. Sessions typically happen several times per week at first, then taper to maintenance.
Botulinum toxin injections are FDA-approved for underarm sweating and also used on hands, feet, and the face. The injections temporarily block the nerve signals that activate sweat glands. Results typically last several months before retreatment is needed. The most common side effects are pain at the injection site, bruising, headache, and temporary muscle weakness in the treated area.
For secondary hyperhidrosis, the most effective “treatment” is addressing whatever is causing it: adjusting a medication, treating a thyroid condition, managing menopause symptoms, or getting evaluated for sleep apnea. Once the underlying trigger is controlled, the sweating usually improves on its own.