Skin · · 7 min read

Excessive sweating: causes, treatments and when to worry

Sweating is how the body cools itself. Hyperhidrosis is sweating when your body does not need to cool down, and it is a treatable medical condition, not a personal failing. Many people have it from childhood with no underlying illness, while sweating that starts later, covers the whole body or wakes you at night can point to another cause worth checking. Treatment runs from the right way to use antiperspirant to prescription options.

Illustration of a plain t-shirt with two water drops above it and a closed bottle with a teal cap beside it

In short

  • Hyperhidrosis means sweating when the body does not need cooling, and it is treatable.
  • It often starts in childhood or adolescence, and most people with it are otherwise healthy.
  • Sweating can also be caused by another health condition or a medicine, so new or whole-body sweating deserves a checkup.
  • Dermatologists build individualized plans with creams, devices, injections, medicines or surgery.
  • Night sweats, or heavy sweating with weight loss, fever or chest pain, should be assessed promptly.

What hyperhidrosis is

The AAD describes hyperhidrosis as excessive sweating that happens even when it is cool or when you are sitting still. It most often affects the palms, underarms, soles or head, but it can affect the whole body. It is not contagious. The NHS adds that sweating can affect the whole body or just certain areas.

MedlinePlus notes that sweat mixed with skin bacteria can cause body odor, and that normal triggers for sweating include heat, exercise, anxiety, fever and menopause.

Causes: no clear reason, or another cause

  1. No obvious cause.The AAD says hyperhidrosis often starts in childhood or adolescence, and most people who develop it are otherwise healthy. Overactive nerves are one explanation.
  2. Another condition.MedlinePlus lists thyroid or nervous system disorders, low blood sugar, infections, fever, anxiety, menopause and cancer among the possible causes of heavy sweating.
  3. Medicines.Some medicines can cause sweating, including some for thyroid conditions, strong pain relievers, fever reducers and some mental health medicines. Withdrawal from alcohol, sedatives or narcotic painkillers can also do it. Never stop a medicine on your own.

A dermatologist can confirm hyperhidrosis and identify its type. If another condition or medicine is the cause, treatment depends on that cause.

Using antiperspirant so it works

The AAD explains that antiperspirants temporarily block your sweat glands, which reduces how much sweat you see. Over-the-counter versions generally help only mild cases. Prescription-strength antiperspirants are usually applied to completely dry skin at bedtime until sweating is under control, then used about once or twice a week.

  1. Dry skin.Apply to completely dry skin, not right after a shower.
  2. Bedtime.Use it at night, which is the AAD's schedule for prescription products. Then follow the label or your clinician's schedule for how often.
  3. Irritated skin.If your skin stings or reddens, tell your pharmacist or dermatologist. A pharmacist can suggest stronger antiperspirants, armpit shields, foot powders or gentler soap substitutes.
  4. Deodorant versus antiperspirant.Both help with body odor, but antiperspirant is the one that reduces sweat.

Everyday measures

  • Wear loose clothing and avoid tight synthetic fabrics such as nylon.
  • Wear absorbent socks and change them at least twice a day if you can.
  • Choose leather shoes and vary your shoes from day to day. Avoid enclosed boots or sports shoes where possible.
  • Notice triggers such as alcohol and spicy food, and cut back if you spot a link.
  • Keep an eye on stress, since the NHS lists it among triggers and anxiety can both cause and result from heavy sweating.

Medical treatments in general terms

If self-help does not work and there is no obvious cause, the NHS and AAD describe these options, which a dermatologist chooses based on where you sweat and how severe it is:

  • prescription antiperspirants and skin creams or cloths for the underarms;
  • iontophoresis for the hands and feet, which sends a mild electric current through tap water, usually in sessions of 20 to 30 minutes;
  • botulinum toxin injections for the underarms, hands, feet or face, with effects that usually appear within 7 to 10 days and last roughly 3 to 10 months;
  • oral medicines that work throughout the body and need ongoing use, which can have side effects;
  • in-office devices for the underarms, and surgery such as sweat gland removal or sympathectomy for severe cases.

The AAD notes that surgery can permanently stop sweating in the treated area, but compensatory sweating in other areas is a common side effect. Treatment aims to control the problem, and a plan usually combines medication, a procedure or both with self-care.

Night sweats

Waking up warm under a heavy blanket is not the same as regularly soaking your sheets. The NHS lists night sweats as a reason to make an appointment with your clinician. MedlinePlus advises contacting a provider if you often sweat during sleep, if you lose weight from sweating, or if sweating lasts a long time or cannot be explained.

Red flags and when to see a doctor

Call 911 if sweating comes with or is followed by chest pain or pressure, shortness of breath or fainting. Contact a clinician promptly if sweating comes with fever, a rapid or pounding heartbeat, or weight loss, since MedlinePlus says these may indicate a problem such as an overactive thyroid or an infection.

The NHS suggests a non-urgent appointment if self-help is not working, if sweating has lasted at least 6 months, if it stops you doing daily activities, if it happens at least once a week, if it happens at night, if you have a family history of excessive sweating, or if you take medicine for another condition. A clinician may order tests if another condition could be causing it.

Questions to ask your clinician

  • Is this hyperhidrosis with no cause, or should I be checked for something else?
  • Could any of my medicines be adding to it?
  • Which antiperspirant strength should I try and for how long?
  • Would iontophoresis or injections suit the area I sweat from?
  • What can I do about skin irritation from treatment?

Questions and answers

Why is bedtime the best time for antiperspirant?

The AAD's schedule for prescription antiperspirants is to apply to completely dry skin at bedtime until sweating is controlled. Dry skin is the key, so avoid applying right after a shower.

Is hyperhidrosis contagious?

No, according to the AAD. It is a medical condition, and the cause can be overactive nerves, another health condition or a medication.

Do botulinum toxin injections last?

They are not permanent. The AAD says their effect usually lasts roughly 3 to 10 months depending on the area, so repeat treatments are needed.

Can sweating be a sign of something serious?

Sometimes. Sweating that is new, whole-body, comes at night or comes with weight loss, fever, a pounding heartbeat or chest pain should be assessed by a clinician.

Does surgery fix excessive sweating?

It can stop sweating in the treated area permanently, but the AAD warns that compensatory sweating elsewhere is a common side effect, so it is usually considered after other options.

Sources

  1. AAD — Hyperhidrosis: Overview
  2. AAD — Hyperhidrosis: Diagnosis and treatment
  3. NHS — Excessive sweating (hyperhidrosis)
  4. MedlinePlus — Sweat
  5. MedlinePlus — Sweating (encyclopedia article)

Sources checked on 29 October 2026.

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