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 medical device 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 and other body areas [link to Saalio pads].
It was the work of Dr Walter Shelley on the effects of tap water on skin that began its use to treat hyperhidrosis.
It was the work of Dr Walter Shelley on the effects of tap water on skin that began its use to treat hyperhidrosis.
A paper from Fred Levit in 1968 describing a simple device really began the development of devices for home and clinic use.
Iontophesis can be used to drive any charged molecule across the skin, sclera or mucous membrane so is used for some drug delivery systems, for example in pain management. Similarly, it can be used to extract some biomarkers form the skin (reverse Iontophoresis).
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.
In some areas of the UK a course of iontophoresis will be offered by dermatology units to evaluate the treatment. On completion, if successful, patients are recommended to purchase their own device for continued treatment at home (see below 'Which device should I buy').
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.
In some areas of the UK a course of iontophoresis will be offered by dermatology units to evaluate the treatment. On completion, if successful, patients are recommended to purchase their own device for continued treatment at home (see below 'Which device should I buy').
How does Iontophoresis Work?
Despite many decades of use, it is still not completely understood how tap water iontophoresis works. A number of theories have been proposed which are either physical or functional. The work of Shelley showed a physical plug of keratin within the tube (duct) leading from the gland to the skin although others could not reproduce this finding.
Others suggest that iontophoresis alters the function of the gland producing the sweat by blocking the nerve signalling the gland or directly affecting the cells that make sweat.
Since iontophoresis is driving ions from the tap water into the skin and the sweat glands, as well as the metal ions in the water (calcium, sodium) it will also send the hydrogen ions (H+) that make up water (H2O).
Hydrogen ions affect the acidity or pH of a solution. One suggestion is that the increase in hydrogen ions (and therefore a lower pH) in the sweat glands alters the way that it functions.
Others suggest that iontophoresis alters the function of the gland producing the sweat by blocking the nerve signalling the gland or directly affecting the cells that make sweat.
Since iontophoresis is driving ions from the tap water into the skin and the sweat glands, as well as the metal ions in the water (calcium, sodium) it will also send the hydrogen ions (H+) that make up water (H2O).
Hydrogen ions affect the acidity or pH of a solution. One suggestion is that the increase in hydrogen ions (and therefore a lower pH) in the sweat glands alters the way that it functions.
What does an iontophoresis device actually do?
The devices produce an electric current at a level specified by the user in milliamps (mA), usually up to 20mA. Once the treatment begins the device detects a circuit has been made and measures the skin resistance and adjusts the voltage to maintain the set current (as in Ohms Law, V=IR). That is the reason why with older devices when a hand or foot was removed from the water bath a shock was felt; as the body part is removed the resistance increases and to maintain the current the voltage increases.
The spike in voltage produces a mild shock, sometimes called the "electric fence effect". More modern devices detect such changes and rapidly reduce the current flow to prevent this happening. Shocks can still sometimes be felt but they are harmless and can usually be prevented by removing hands or feet slowly from the water baths.
The spike in voltage produces a mild shock, sometimes called the "electric fence effect". More modern devices detect such changes and rapidly reduce the current flow to prevent this happening. Shocks can still sometimes be felt but they are harmless and can usually be prevented by removing hands or feet slowly from the water baths.
What is the iontophoresis protocol?
Most manufacturers of iontophoresis devices have slightly different protocols for how often the treatment sessions should take place initially to achieve sweat reduction. A little like the mechanism of iontophoresis, there is no overall consensus in this regard. The device instructions for use (IFU) should always be followed.
From our long experience with iontophoresis for hyperhidrosis and reviewing over twenty-five published clinical trials, precisely adhering to very specific protocols is not always required. Treatments that work usually treat three or four times in the first week, two to three times in the second week (by which time it would be expected that sweat reduction is noticeable) then one or two treatments in the third and fourth weeks. By that stage sweating would be expected to be controlled.
Treatment session durations should be 15 to 20 minutes. The current levels at the beginning of treatment are likely to be low (just a few milliamps) as this is all that can be comfortably tolerated. At each subsequent treatment it would be expected that the current could be increased slightly. The average current used is usually between 15 and 20 mA for the hands and feet, but some people get success with much lower currents because everybody’s skin is different.
From our long experience with iontophoresis for hyperhidrosis and reviewing over twenty-five published clinical trials, precisely adhering to very specific protocols is not always required. Treatments that work usually treat three or four times in the first week, two to three times in the second week (by which time it would be expected that sweat reduction is noticeable) then one or two treatments in the third and fourth weeks. By that stage sweating would be expected to be controlled.
Treatment session durations should be 15 to 20 minutes. The current levels at the beginning of treatment are likely to be low (just a few milliamps) as this is all that can be comfortably tolerated. At each subsequent treatment it would be expected that the current could be increased slightly. The average current used is usually between 15 and 20 mA for the hands and feet, but some people get success with much lower currents because everybody’s skin is different.
Should direct/continuous or pulsed current be used?
A direct current is a continuous current whereas a pulsed current is the same current but pulsed at a high frequency to reduce the intensity. The pulsed current means it is on 50% of the time and off 50% of the time so overall delivers 50% of the current dose compared with continuous current. When possible, a direct/continuous current is likely to achieve better results.
Pulsed current is recommend for those with sensitive skin, treating the underarms and for the treatment of children.
Pulsed current is recommend for those with sensitive skin, treating the underarms and for the treatment of children.
what does iontophoresis feel like?
When treating the hands and feet, the current should be set so that a mild tingling sensation is felt in the treated skin. It should not be uncomfortable and certainly should not be painful. The current should be adjusted to a level that is comfortable and bearable for the duration of the treatment session. There is no benefit and it can even harm if too high a current is used. When treating other areas of the body, such as the underarms, some people feel very little. In these areas the skin is much thinner so the current levels used must be lower and set according to the manufacturer’s instructions for use (IFU) supplied with the device.
what about maintenance treatment?
Maintenance treatment sessions are then required to keep the sweating under control. The average time btween these sessions is one week although some people can go a few weeks before needing maintenance treatment. It is important to undertake maintenance treatment sessions as soon as the skin begins to feel clammy before the heavy sweating returns. If maintenance is delayed for too long and the excessive sweating has returned, it is best to begin the initial treatment protocol again.
is there anyone who cannot have iontophoressis?
While iontophoresis is considered a safe treatment without many adverse effects there are certain circumstances where iontophoresis should not be performed. These include:
- Pregnancy
- Cardiac pacemakers or implanted cardioverter defibrillator (ICD)
- Cardiac arrhythmias
- Metal (usually copper) uterine coils
- Metal implants in the line of the current
- Peripheral neuropathy of the area to be treated
- Pregnancy
- Cardiac pacemakers or implanted cardioverter defibrillator (ICD)
- Cardiac arrhythmias
- Metal (usually copper) uterine coils
- Metal implants in the line of the current
- Peripheral neuropathy of the area to be treated
what can be done if iontophoresis is not reducing sweating?
Some people don’t respond to the initial treatment sessions. Sometimes this is because their skin requires more current exposure or they have only managed to tolerate low currents well into the protocol.
Our advice would be to not give up. Continue treating for up to three times a week or on alternate days. If the currents tolerated after five or six treatment sessions are below 10 mA because that is as much as can be tolerated, try treating for longer each session (20 minutes rather than15 minutes).
Our advice would be to not give up. Continue treating for up to three times a week or on alternate days. If the currents tolerated after five or six treatment sessions are below 10 mA because that is as much as can be tolerated, try treating for longer each session (20 minutes rather than15 minutes).
does tap water hardness affect iontophoresis?
Iontophoresis requires ions in the tap water to exert its effects. Rainwater is very soft because it has yet to pick up any minerals. The ions in the water are dissolved minerals that are picked up as the rainwater is filtered through the soil and rocks. The hardness of the tap water depends on the local geology.
Water in the south eastern half of the UK passes through chalk or limestone and picks up a lot of mineral (calcium carbonate) so is very hard. Further west and north the bedrock becomes more granite in nature and fewer minerals are picked up by the water so it is softer. The extreme west of Wales, South West England and most of Scotland have very soft water.
The water hardness in your area can be found by searching your local water supply company and there are many maps online illustrating the variations around the country.
Water in the south eastern half of the UK passes through chalk or limestone and picks up a lot of mineral (calcium carbonate) so is very hard. Further west and north the bedrock becomes more granite in nature and fewer minerals are picked up by the water so it is softer. The extreme west of Wales, South West England and most of Scotland have very soft water.
The water hardness in your area can be found by searching your local water supply company and there are many maps online illustrating the variations around the country.
what can be done if your tap water is soft?
Opinions vary on how much soft tap water affects iontophoresis but if you live in a soft water area and are not getting results from iontophoresis then try one of the following:
Adding a teaspoon of bicarbonate of soda or table salt to each of the water baths is a simple, cheap and popular method. Alternatively, using bottled mineral water sourced from a hard water area that is known to be high in calcium bicarbonate and therefore hard. Bottled waters from areas such as the south-eastern half of the UK, midlands and East Wales are hard. Carbonated waters from Europe are also ideal (Badoit, Perrier, San Pelligrino).
Adding a teaspoon of bicarbonate of soda or table salt to each of the water baths is a simple, cheap and popular method. Alternatively, using bottled mineral water sourced from a hard water area that is known to be high in calcium bicarbonate and therefore hard. Bottled waters from areas such as the south-eastern half of the UK, midlands and East Wales are hard. Carbonated waters from Europe are also ideal (Badoit, Perrier, San Pelligrino).
how successful is iontophoresis?
If the treatment protocol is adhered to and the time is taken to do the treatments, iontophoresis is about 70 - 80% successful, which for a medical intervention is good. There are some people for whom it will not work. Many of the cases where it is not successful, though, are when the treatment protocol has not been completed or the patient did not like the sensation felt on the skin during treatment.
why are iontophoresis devices so expensive?
They are class IIa medical devices that have to be CE or UKCA marked to be allowed to be sold in the UK. To comply with all the standards (electrical, materials, risk reduction and safety) they have to meet, significant costs in the design and development stages are incurred by the manufacturer. For more information on UK government regulations regarding the manufacture and sale of medical devices click here.
Once devices are on the market, the MHRA - who govern medicines and medical devices in the UK - introduced new requirements for monitoring incidents in 2025.
There is a reasonable upfront payment for the device but properly looked after it will last many years. Some companies offer finance or payment by instalments.
If it is bought for your own personal use, the device (but not separately sold accessories) is exempt from VAT because it is for treating a medical condition.
There are many local charities that exists to help people who live in that community so it is worth searching the web or asking at your local library. The Turn2Us website has a good search facility of local charities.
Once devices are on the market, the MHRA - who govern medicines and medical devices in the UK - introduced new requirements for monitoring incidents in 2025.
There is a reasonable upfront payment for the device but properly looked after it will last many years. Some companies offer finance or payment by instalments.
If it is bought for your own personal use, the device (but not separately sold accessories) is exempt from VAT because it is for treating a medical condition.
There are many local charities that exists to help people who live in that community so it is worth searching the web or asking at your local library. The Turn2Us website has a good search facility of local charities.
which iontophoresis device should I buy?
All iontophoresis devices achieve the same core function; maintaining a set current by adjusting the voltage according to the skin resistance.
Beyond the core function of the device, there are some key features and considerations to look out for and take into account:
Beyond the core function of the device, there are some key features and considerations to look out for and take into account:
Battery / Mains power
Battery powered devices have been known to have occasional current spikes. While these spikes aren't dangerous, and vary from model to model, they do produce some discomfort in the form of a mild electric shock.
Devices that plug into a wall socket with a transformer, the same as a laptop or kitchen appliance, run more smoothly, supplying a consistent current, and avoiding the need to change batteries.
Devices that plug into a wall socket with a transformer, the same as a laptop or kitchen appliance, run more smoothly, supplying a consistent current, and avoiding the need to change batteries.
Recommendation
In our opinion, the current best in class device is The Saalio. It is the latest device to appear on the market, is mains powered and sports a number of safety and quality features that clearly put it ahead of the competition. It will also soon be offering finance options for those on a restricted budget.
Here are some cheaper (but still well made) devices: Sweatstop, Sweatguard
Here are some cheaper (but still well made) devices: Sweatstop, Sweatguard
What to avoid
You may come across homemade devices while browsing online. While it may be obvious for some, we strongly recommend avoiding any device that isn't CE or UKCA marked, considering the nature of the device and how it functions. use of a unregulated device could lead to serious injury.
what are the possible side effects?
Side effects with iontophoresis treatment are uncommon and mild if the instructions are followed carefully.
Any cuts in the skin exposed to the current should be covered with petroleum jelly before treatment otherwise pain may be felt.
Reddening of the skin especially at the water level is quite common but settles down after the treatment session.
If skin comes into direct contact with the electrodes which should be covered by a grill or sponge then skin burns can occur.
Shocks can occur, especially with older designed devices, if the hands or feet are removed too quickly from the water baths.
As treatment progresses the skin can sometimes, paradoxically, feel dry. It is recommended to use skin emollients or moisturisers to maintain the oils on the skin surface.
Any cuts in the skin exposed to the current should be covered with petroleum jelly before treatment otherwise pain may be felt.
Reddening of the skin especially at the water level is quite common but settles down after the treatment session.
If skin comes into direct contact with the electrodes which should be covered by a grill or sponge then skin burns can occur.
Shocks can occur, especially with older designed devices, if the hands or feet are removed too quickly from the water baths.
As treatment progresses the skin can sometimes, paradoxically, feel dry. It is recommended to use skin emollients or moisturisers to maintain the oils on the skin surface.
