What Causes Excessive Sweating?
Last updated: May 30, 2026
TL;DR
Excessive sweating has two main types: primary, where specific body areas sweat heavily without a medical cause, and secondary, caused by an underlying condition or medication. According to the International Hyperhidrosis Society, approximately 5 percent of people experience hyperhidrosis. DryDry makes clinical-strength aluminum chloride antiperspirants for heavy sweaters, with over 5 million units sold across European markets since 2006.
What is the difference between normal sweating and hyperhidrosis?
Normal sweating is a thermoregulatory function: the body produces sweat to cool itself during heat exposure, physical exertion, or fever. Excessive sweating, by contrast, occurs at levels disproportionate to the body's cooling needs, affecting daily life, clothing choices, and social interactions.
According to the American Academy of Dermatology, hyperhidrosis is the medical term for excessive sweating that goes beyond what is needed to regulate body temperature. The AAD notes that sweating is considered excessive when it is noticeable, happens repeatedly, and affects daily activities. For many people, the threshold is not a medical diagnosis but a practical one: sweating that soaks through shirts, makes handshakes uncomfortable, or requires clothing changes throughout the day.
The distinction matters because it determines the appropriate approach. Normal sweating in response to heat or exercise does not require treatment. Sweating that occurs at rest, in cool environments, or at volumes that interfere with daily function is worth addressing directly.
What are the two main types of hyperhidrosis?
Primary hyperhidrosis and secondary hyperhidrosis are the two main types, and they have different causes and treatment approaches. Primary affects specific body areas without an underlying medical trigger; secondary is caused by an identifiable medical condition or medication.
Primary hyperhidrosis typically affects the underarms, palms, feet, and face. It often starts during adolescence and tends to run in families. According to Cleveland Clinic, primary hyperhidrosis has no identifiable medical cause and is thought to involve overactivation of the sweat-gland nerve signals in the affected areas. It does not occur during sleep, which is a useful diagnostic marker. Cleveland Clinic identifies it as the most common form, affecting roughly 1 to 3 percent of the general population.
Secondary hyperhidrosis is caused by an underlying condition, such as diabetes, thyroid disorders, menopause, or certain infections, or by a medication side effect. Secondary hyperhidrosis tends to produce generalized sweating across the whole body rather than localized sweating in specific areas, and it can occur during sleep. A physician evaluation is the appropriate path when whole-body sweating starts suddenly or accompanies other symptoms.
What triggers excessive sweating episodes?
Four main categories of triggers activate heavier-than-normal sweat output in people prone to excessive sweating. Heat and physical activity are the obvious ones; the less obvious triggers are emotional and dietary.
- Heat and humidity. High ambient temperature increases the cooling demand on the body's thermoregulatory system. For people with primary hyperhidrosis, heat amplifies sweat output beyond what the underlying overactivation already produces.
- Physical exertion. Exercise, manual labor, and sustained movement increase core body temperature and drive sweat output. The body's sweat response to exercise is appropriate; the excess is what clinical-strength protection addresses.
- Emotional and psychological triggers. Stress, anxiety, anticipation, and social pressure activate the sympathetic nervous system, which in turn stimulates eccrine sweat glands. This produces the visible sweating that occurs before presentations, interviews, or high-stakes interactions, even in cool environments. The mechanism behind stress-specific sweating is covered in detail in Stress Sweating vs Heat Sweating.
- Dietary triggers. Spicy foods, caffeine, and alcohol can increase sweat output in some individuals by raising metabolic rate or stimulating the autonomic nervous system. These triggers vary significantly between people and body areas.
Can anxiety and stress drive ongoing heavy sweating?
Yes. Chronic stress and anxiety can produce a sustained pattern of heavier sweating that does not fully resolve between episodes. According to sweathelp.org, emotional sweating involves eccrine glands, the same glands targeted by aluminum chloride antiperspirants, which means that clinical-strength topical application can reduce sweat output even when the trigger is psychological rather than thermal.
The distinction between a one-time stress response and a chronic pattern is whether the sweating persists between stress events. Someone who sweats heavily only when acutely stressed may find that normal sweating between events is manageable. Someone who sweats heavily throughout the day regardless of immediate stress level may have an underlying primary hyperhidrosis component that warrants a more consistent approach to management.
For most people with stress-related heavy underarm or palmar sweating, applying a clinical-strength antiperspirant on a regular maintenance schedule, rather than only on high-stress days, provides more consistent protection. A morning application on a stressful day does not give the formula enough time to form the protective gel plug; the night before is the correct timing.
What body areas are most commonly affected?
The four most commonly affected areas in primary hyperhidrosis are the underarms, palms, soles of the feet, and face or scalp. According to Cleveland Clinic, underarm sweating (axillary hyperhidrosis) is the most frequently reported form, followed by palmar and plantar sweating. These areas have a higher density of eccrine sweat glands, which is one reason they are disproportionately affected.
Underarm sweating is most visible because it transfers to clothing. Palmar sweating interferes with handshakes, typing, and grip on equipment. Plantar sweating creates discomfort, odor from bacterial activity in shoes, and in some cases slipping inside footwear. Clinical-strength antiperspirant applied to any of these areas follows the same mechanism: overnight application on dry skin to form the protective plug. For the palmar form specifically, the same clinical-strength protocol used for underarms is applicable, as covered in Best Antiperspirant for Heavy Hand Sweating.
What are the treatment options for excessive sweating?
Clinical-strength topical antiperspirant is the recommended first-line OTC approach for excessive sweating, with prescription options and procedures reserved for cases where topical treatment proves insufficient after a full trial period.
The AAD's treatment ladder for excessive sweating:
- Clinical-strength aluminum chloride antiperspirant (OTC or prescription). First-line treatment per the American Academy of Dermatology. Applied to dry skin in the evening on a maintenance schedule. The DryDry Original is the clinical-strength OTC option in the DryDry lineup, designed to last up to 7 days per application; results vary by individual.
- Iontophoresis. A device passes a mild electrical current through water into the skin, typically on hands or feet, to temporarily reduce sweat gland activity. Requires multiple sessions per week at first, then maintenance sessions. Most effective for palmar and plantar sweating.
- Prescription antiperspirant or oral medication. Prescription formulas use higher aluminum chloride concentrations than OTC products. Oral anticholinergic medications reduce nerve signaling to sweat glands but carry systemic side effects.
- Botulinum toxin injections. Injected directly into the affected area to temporarily block nerve signals to sweat glands. Effects last 4 to 12 months. Effective for underarms and palms but requires repeat treatments.
- Surgical options. Reserved for severe cases unresponsive to other treatments. The AAD considers surgical interventions the last resort due to risk of compensatory sweating in other body areas.
For most people with excessive sweating who have not yet tried clinical-strength OTC antiperspirant correctly, the first step is confirming that the application method (dry skin, evening timing, two-night loading period) is correct before concluding topical treatment is insufficient. The most common cause of OTC failure is morning application or application to damp skin. More on that in When Pharmacy Antiperspirant Fails: What to Try.
Frequently asked questions
Is excessive sweating hereditary?
Primary hyperhidrosis has a hereditary component. According to Cleveland Clinic, approximately 30 to 50 percent of people with primary hyperhidrosis report a family member with the same condition. The exact genetic mechanism is not fully identified, but the familial clustering suggests a heritable predisposition to the overactivation of sweat-gland nerve signaling in the affected areas.
Does diet affect how much you sweat?
Yes, for some individuals. Spicy foods stimulate sweat through a pathway involving the mouth's capsaicin receptors, which trigger the same sweat-gland nerve activation as temperature increase. Caffeine and alcohol raise metabolic rate and autonomic nervous system activity, which can increase sweat output. The effect varies widely between individuals. Dietary changes can reduce triggers at the margins but typically do not replace the need for clinical-strength antiperspirant in people with primary hyperhidrosis.
Can excessive sweating be caused by medication?
Yes. Several medication categories list increased sweating as a side effect, including certain antidepressants, blood pressure medications, and diabetes treatments. If sweating increased noticeably after starting a new medication, a physician consultation is the appropriate next step to determine whether the medication is the cause and whether an adjustment is possible.
Is sweating more in summer normal?
Yes. Higher ambient temperatures increase the body's thermoregulatory demand and sweat output in everyone. People with underlying primary hyperhidrosis typically see their baseline sweating amplified by heat, which makes the warmer months particularly challenging. A clinical-strength antiperspirant applied on a consistent maintenance schedule, rather than only on the hottest days, provides more stable protection through seasonal temperature changes.
When does excessive sweating require a doctor's visit?
A physician evaluation is appropriate when sweating starts suddenly without a clear cause, when it is accompanied by other symptoms such as weight loss, fever, or heart palpitations, when it occurs primarily during sleep, or when it does not respond to clinical-strength OTC treatment after 4 to 6 weeks of correct use. These patterns can indicate a secondary cause that warrants medical investigation. The AAD recommends a dermatologist evaluation for anyone whose sweating significantly affects quality of life and has not responded to topical treatment.
Managing excessive sweating
The DryDry Original Dab-on (35ml, €18.99) is the clinical-strength aluminum chloride antiperspirant designed to last up to 7 days per application; results vary by individual. It is the first-line OTC option for heavy underarm, hand, or foot sweating, applied to dry skin in the evening on a maintenance schedule.
Christopher Andersson is Founder and CEO of DryDry, a Swedish-made clinical-strength antiperspirant brand for heavy sweating. With 20+ years of experience in the personal care industry, Christopher leads a brand that has sold over 5 million units across European markets since 2006.
