How can we sweat less?

Perspiration is mainly regulated by the eccrine glands, activated in response to an increase in body temperature, and by the apocrine glands, which are more sensitive to emotional stimuli such as stress. Certain everyday factors can intensify their activity. Heat, poorly breathable clothing or inadequate moisture wicking promote the activation of the eccrine glands, which then increase their output in an attempt to cool the body down. Conversely, natural materials such as cotton or linen facilitate the evaporation of sweat, thereby reducing the overheating signals sent to the nervous system and, indirectly, the production of sweat.

Diet and nutrition also play a significant role, as do emotions. Spicy foods, alcohol or caffeine can stimulate the sympathetic nervous system, leading to an increase in sweating. In the same way, stress and anxiety preferentially activate the apocrine glands via the release of adrenaline, which explains why some forms of perspiration occur independently of the ambient temperature. Monitoring one’s diet and trying to relax can therefore help to modulate sweating. Finally, showering after exertion, carefully drying areas prone to sweating and changing clothes regularly all help to limit the accumulation of sweat on the skin’s surface.

Without blocking perspiration, these simple measures help you live with it more comfortably.

In cases of localised sweating, for example in the armpits, on the hands, feet or on the face, antiperspirants are generally the first-line option.

Unlike deodorants, which act mainly on odours, antiperspirants aim to directly reduce the production of sweat. Their effectiveness relies primarily on the presence of aluminium salts, which can form temporary plugs inside the sweat ducts. This partial obstruction limits the flow of sweat to the surface of the skin, without completely blocking the function of the glands. This mechanism acts mainly on the eccrine glands, which are responsible for the majority of perspiration. Their effectiveness is well established in mild to moderate forms of localised hyperhidrosis, particularly in the underarms, but also on the palms of the hands and the soles of the feet, with formulations adapted to these areas.

The use of aluminium salts is, however, a subject of debate. Their ability to reduce perspiration is well documented, but questions remain regarding their cutaneous absorption, their passage into the bloodstream and their long-term effects. To date, the available data do not allow any conclusion to be drawn of a proven risk under normal conditions of use, but this uncertainty may encourage caution.

Less familiar to the general public, iontophoresis is nonetheless an interesting option for reducing excessive sweating, particularly on the hands and feet. This technique involves passing a low-intensity electric current through the skin, generally via water baths in which the areas to be treated are immersed. Although its mechanism of action is not fully understood, several hypotheses have been proposed: temporary obstruction of the sweat ducts, modulation of local nerve activity, or changes in the skin environment that may limit sweat secretion.

In practical terms, treatment begins under the supervision of a healthcare professional, in order to learn how to use the device correctly and to adjust the settings. Each session lasts around 20 minutes, during which the hands or feet are placed in trays filled with water. At the beginning, sessions are relatively frequent, often 2 to 3 times per week, until a visible improvement is achieved. Once sweating has been reduced, weekly maintenance sessions, or sometimes every two weeks, help to maintain the results. After appropriate training, it is entirely possible to carry out the sessions at home using a dedicated device.

The effectiveness of iontophoresis is well documented, with reductions in sweating that can exceed 80% after several sessions, and an effect that is sustained over time if the treatment is continued regularly.

Adverse effects are generally mild and transient, such as tingling, a moderate burning sensation or redness. In some cases, the skin may become dry or slightly irritated, which can be managed by increasing the interval between sessions or applying a moisturising treatment. Iontophoresis is, however, contraindicated in certain individuals, particularly in cases of pregnancy or in those with a cardiac pacemaker.

Iontophoresis can be seen as an intermediate solution for excessive sweating : more effective than antiperspirants, but less invasive than medical options.

Botulinum toxin, produced by the bacterium Clostridium botulinum, is now regarded as one of the most effective options for reducing localised excessive sweating. Its mechanism of action is well understood: it blocks the release of acetylcholine, a neurotransmitter that plays a key role in activating the sweat glands. Under normal conditions, this nerve signal triggers sweat production in response to heat or stress. By inhibiting this transmission, botulinum toxin temporarily prevents stimulation of the glands, which markedly reduces sweat production in the treated areas.

Injections must be carried out by a healthcare professional, using very fine needles. The protocol varies according to the area treated: around fifteen injections per armpit may be required, and up to several dozen for the hands. The session lasts on average around twenty minutes, and a local anaesthetic cream can be applied beforehand to improve comfort. The effectiveness of this technique has been confirmed by several clinical studies.

The effects are not immediate but generally appear within a few days, with a maximal benefit observed after several weeks. The results persist on average for 6 to 7 months, after which the activity of the sweat glands gradually resumes, requiring further injections to maintain the effect. Adverse effects are most often mild and transient: pain at the injection site, redness, swelling, and occasionally slight muscle weakness or headaches.

Finally, it is important to be aware of certain precautions. Injections of botulinum toxin are contraindicated in pregnant or breastfeeding women, as well as in individuals with neuromuscular disorders, due to its effect on nerve transmission. More broadly, it is essential not to inhibit an excessively large area of sweat glands, as perspiration plays a key role in thermoregulation. When properly supervised, however, this technique is a good option for localised and treatment-resistant forms of excessive sweating.

When sweating is widespread, medicinal treatments may be considered.

The most commonly used are anticholinergic agents, which act by blocking the action of acetylcholine, the neurotransmitter involved in activating the sweat glands. Unlike topical preparations or localised injections, these medicines have a systemic effect, which makes it possible to reduce sweating in several areas of the body simultaneously.

However, this systemic action is often accompanied by adverse effects, linked to the role of acetylcholine in numerous physiological functions. Patients may therefore experience dry mouth, reduced tear production, digestive disturbances or even difficulties with concentration. These effects limit their use, particularly over the long term, and explain why these treatments are generally reserved for moderate to severe forms of hyperhidrosis, when other options prove insufficient.

In the most severe and treatment‑resistant forms of hyperhidrosis, surgical options may be considered, particularly when topical and medical treatments have not led to sufficient improvement. The best‑known technique is thoracic sympathectomy, mainly indicated in cases of excessive sweating of the hands and armpits. It is designed to act directly on the nervous system responsible for activating the sweat glands.

The procedure consists of interrupting a portion of the sympathetic nerve, located along the spine, which transmits the signals that trigger sweating. It is carried out under general anaesthesia, most often by thoracoscopy, a minimally invasive technique that allows a camera to be introduced into the chest through a small incision at the level of the armpit. Once the nerve has been located, it is cut over a short distance. This procedure is generally quick and the results are often immediate and long-lasting, with a marked reduction, or even disappearance, of sweating in the targeted areas.

However, despite its effectiveness, thoracic sympathectomy remains a treatment of last resort, due to its invasive nature and potential side effects.

The main issue is compensatory hyperhidrosis, which corresponds to an increase in sweating in other areas of the body, such as the back or the chest. This phenomenon may be more or less pronounced depending on the individual. Therefore, this procedure requires a thorough assessment and discussion with a healthcare professional, in order to carefully weigh the expected benefits against the associated risks.

• DAHL J. C. & al. Treatment of hyperhidrosis manuum by tap water iontophoresis. Acta Dermato-Venereologica (1989).

• LOWE N. J. & al. Botulinum toxin type A in treatment of bilateral primary axillary hyperhidrosis: Randomised, parallel group, double blind, placebo controlled trial. The BMJ (2001).

• UNAL G. & al. Safe control of palmoplantar hyperhidrosis with direct electrical current. International Journal of Dermatology (2002).

• SWICK B. L. & al. Treatment options for hyperhidrosis. American Journal of Clinical Dermatology (2012).

• BAKER D. M. & al. Treatment of primary hyperhidrosis with oral anticholinergic medications: A systematic review. Journal of the European Academy of Dermatology and Venereology (2016).

• FOSSELMAN D. & al. Hyperhidrosis: management options. American Family Physician (2018).

• BAKER L. B. Physiology of sweat gland function: The roles of sweating and sweat composition in human health. Temperature (2019).

• CHA J. & al. The etiology, diagnosis, and management of hyperhidrosis: A comprehensive review. Journal of the American Academy of Dermatology (2019).

• DARBRE P. D. & al. Personal care products and human health. Academic Press (2023).