You wake up in the middle of the night, the pillow is damp, your pyjama top soaked through — and the heating isn't even running. Night sweats are not just uncomfortable; they can be a signal from your body that something is not quite right. The causes range from harmless factors like an overly warm bedroom to medication side effects or conditions that require treatment. Here you will find out how to assess your night sweats, which medications may be responsible, and when to see a doctor.
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Night sweats accompanied by unexplained weight loss, fever, or swollen lymph nodes should be investigated by a doctor without delay.
Sweating at night is not automatically "night sweats" in the medical sense. Waking up slightly damp because the duvet is too warm is entirely normal. It becomes medically significant when you regularly sweat so heavily that you need to change your nightwear and bedding — despite sleeping at a reasonable temperature.
Doctors distinguish three levels of severity:
| Grade | Description | Action needed |
|---|---|---|
| Grade 1 | Light sweating on the head and torso — clothing damp, no change needed | Monitor |
| Grade 2 | Clothing soaked through, bedding change needed | Investigate the cause |
| Grade 3 | Complete drenching — pyjamas, sheets, sometimes the mattress affected | See a doctor promptly |
From Grade 2 onwards, the cause should be investigated medically — especially if it happens regularly.
Many active substances can cause night sweats as a side effect. According to research, 5–14% of people taking antidepressants experience nocturnal hyperhidrosis. The most commonly implicated are:
| Medication | Mechanism |
|---|---|
| Citalopram, Escitalopram (antidepressants) | Most common SSRI side effect — affects 5–14% of users |
| Prednisolone (cortisone) | Stimulates metabolism and can trigger sweating |
| Metformin | During nocturnal hypoglycaemia — often accompanied by heart palpitations and trembling |
| Acetaminophen (paracetamol), ibuprofen | Sweating as the fever-reducing effect wears off |
| Semaglutide (Ozempic/Wegovy) | Night sweats as a recognised side effect |
The menopause (perimenopause) is the best-known hormonal cause of night sweats — up to 75% of women are affected. Falling oestrogen levels disrupt the temperature regulation centre in the hypothalamus: the body "believes" it is overheating and responds with sweating. An overactive thyroid, hormonal fluctuations during the menstrual cycle, or an overdose of levothyroxine can also cause night sweats.
Colds, flu, and other feverish infections frequently trigger night-time sweating — this type of night sweats usually resolves within 3–7 days. Chronic infections (e.g. tuberculosis, HIV) and bacterial endocarditis can also cause night sweats.
Psychological stress activates the sympathetic nervous system. The body responds — even during sleep — with sweating, heart palpitations, and restlessness. Chronic stress can lead to persistent night-time sweating.
Alcohol dilates blood vessels and disrupts temperature regulation. Spicy food can have the same effect. Heavy alcohol consumption in the evening is one of the most common harmless causes of night sweats.
Cool the bedroom to 61–64 °F (16–18 °C), use breathable cotton or linen bedding, avoid synthetic duvets and pillows. Keep a second set of bedding within reach so you can change quickly after heavy sweating.
Avoid alcohol, spicy food, and heavy meals in the evening. Avoid caffeine from 2 PM onwards. A brief relaxation exercise before bed (progressive muscle relaxation or the 4-7-8 breathing technique) can reduce stress-related sweating.
Sage tea (2–3 cups per day) is a traditional remedy for excessive sweating — sage leaves contain essential oils that inhibit the sweat glands. Lavender oil on the pillow may have a calming effect and support falling and staying asleep.
Never stop medications on your own. Talk to your doctor — changing the time of administration (e.g. taking prednisolone in the morning rather than the evening), a dose adjustment, or a switch to an alternative preparation often helps.
If the night sweats started around the same time as a new prescription or dose increase, it is worth reviewing your medication.
Digital medication plan: Record all your preparations and see whether the night sweats correlate with a medication change.
Interaction check: Find out whether your combination of medications is intensifying the sweating.
Dose reminder: Consistent intake prevents rebound effects (e.g. blood sugar fluctuations with metformin).
Register for free nowOccasional sweating at night is usually harmless. See a doctor if:
To help your doctor find the cause quickly, prepare the following information:
brite brings structure to your observations and helps you identify the cause of your night sweats.
