Tap water iontophoresis (pronounced ahy-on-tuh-fuh-ree-sis) has been used in the treatment of hyperhidrosis for many decades. It is particularly effective for treating hyperhidrosis of the hands, feet and underarms. The process requires a dedicated machine to pass a low voltage electrical current through the skin of the hands or feet which are immersed in shallow trays of water. Special pads, or electrodes are required for the treatment of the underarms.

From very early on in life we are taught not to mix water and electricity but iontophoresis is very safe with no significant or serious side effects.

Hyperhidrosis UK - Iontophoresis Hands

Tap water iontophoresis works for about 70-80% of patients. The exact mechanism behind how it works is not known although there are numerous theories. What is known is that it requires some of the particles found in tap water (the ions) to work. That is why people who use the machines where their tap water is soft do not get such good results as those where the water is hard. The south eastern half of the Britain from Teeside to Somerset has moderately to very hard water while areas north and west of this line including much of Devon, Cornwall, Wales, Scotland and Northern Ireland have soft water.

The machines for iontophoresis can either provide a continuous direct current or a pulsed current or capapble of both. Generally a direct current is suitable for the treatment of hands and feet and pulsed current is used for the underarm areas and when the skin is sensitive.

Successful treatment requires seven sessions over a four week period initially to get the hyperhidrosis controlled then requires top-up treatments as needed which varies from every week to every two weeks. It usually takes at least four sessions before there is any noticeable reduction in sweating. Each treatment session takes about 20 minutes for the hands and 30 minutes for the feet.

At first very little happened. I kept going and, after session four, hey presto! The sweating stopped. That’s right, stopped. I remember meeting some new people during the second week of treatment, and being able to shake hands confidently. I could take my wellies off after a walk, and not leave damp footprints all over the floor. I could sit at my desk and not find myself dripping with sweat as I worked.
Hyperhidrosis UK - Iontophoresis Axilla

Recommended Treatment for Hands is 20 mins at 20mA
Recommended Treatment for Feet is 30 mins at 25mA

Enter the number of mA you are able to treat yourself at and press the corresponding button to calculate the time we think you should treat yourself at.


More information on iontophoresis can be found on