Essentials on electrodes for TENS treatment

The TENS electrode is used during electrotherapy treatments, (TENS – nerve stimulation, pain relief; EMS – muscle stimulation; Microcurrent – pain relief, healing stimulation, denervated – treatment of peripheral paralysis) and is an essential tool. The pulse is delivered from the device to your body through an adhesive pin attached to the skin. Without it, there is no treatment and no effect. In this article, I summarise the most important facts to help you make the right choice.

The TENS electrode is a consumable item that wears out after a few treatments and requires replacement.

Key features of the TENS electrode

• connector type (needle, patent, clip, other)
• size and shape (square, rectangular, round, oval, other)
• layers (overlay, gel, conductive, adhesive)
• use (single or multiple application)
• conductivity.

Type of connector

Cables from electrotherapy device manufacturers in general

• PIN or
• patent (SNAP) or
• other non-standard connectors

The larger, medical-grade manufacturers usually have standard PIN or SNAP connectors, so you can connect any PIN or SNAP electrode to these. You just need to pay attention to the termination of your device’s cable.

The connectors on some medical wellness manufacturers (e.g. Omron, Beurer, Vivamax) are not standard. The standard ones will not “fit”.

This is a marketing ploy. You buy the device cheap and later realize that the replacement electrode costs 8-9 thousand forints. If you have to use the device regularly, it becomes many times more expensive.

Size and shape

You can find the most varied sizes and shapes on the market. The most common shapes and sizes

• square (4×4 or 5x5cm)
• rectangle (5×9 or 5x10cm)
• circle (2.3, 3, 5 cm diameters)
• oval (3×5, 7.5×13 cm)
• pillar and other shapes.

When choosing the size, take into account the area to be treated!

Obviously, a 7.5×13 cm oval pair of electrodes will not fit on your face, but round electrodes with a diameter of 2.5 – 3cm are suitable.

For your calves, on the other hand, the larger 7.5x13cm oval electrodes are fine.

For general analgesia (TENS or MENS), a 4-5cm square electrode is suitable. I recommend the same for muscle stimulation of the neck, shoulders, arms and motor points (larger muscles: thighs, abdomen, breasts, back).

For muscle stimulation, I recommend the 5×9, 5x10cm electrodes as electrodes further away from the motor point.

Note that for stimulation, a current of 2mA/cm2 is generally recommended. That is, a 5×5 electrode is 25cm2, so the recommended maximum current is 50mA.

The smaller the electrode, the smaller the area over which the current is concentrated. A higher current will cause a more unpleasant sensation.

Layers, materials

The materials and thickness of the electrode determine the flexibility of the electrode. The thicker and stiffer an electrode is, the less it will pick up the contours of the body.

Inexpensive electrodes usually consist of three layers: adhesive, gel and covering layers. The gel layer conducts the current and distributes it within.

Better quality electrodes (types: PALS, Ultrastim, ValueTrode) contain two gel layers, an adhesive, a conductive layer and a covering layer. The double gel layer provides a more even current distribution, which reduces the unpleasant pinching sensation associated with the treatment.

The top layer is usually textile, foam, paper or a special material.

Thicker and stiffer electrodes will smooth the skin properly on larger muscles, thighs, back, abdomen, and buttocks. However, they are not suitable for treating a thin wrist, neck, etc., because they do not lie on strong hairlines.

Cheap electrodes are stiff, their edges curl up in the hairline, and they sag. As a result, the current delivery is concentrated in a small area.

The PALS electrodes represent the highest level. They contain stainless steel mesh and are extremely thin and flexible. And the mesh covering the entire surface ensures perfect current distribution over the entire surface.

The UltraStim electrodes have a silver fibre mesh as the conductive layer. It also allows excellent current distribution but is slightly stiffer.

The general-purpose ValueTrode electrodes do not have a separate conductive filament. The current is conducted into the double gel layer, which provides good distribution, but the electrode is more rigid.

How to choose an electrode?

Pain Reliever (TENS and Microcurrent) for treatments

Use of ValueTrode electrodes is generally sufficient. They are suitable for TENS and Microcurrent treatments with a diameter of 40-50mm. Stick them around the pain and perform the stimulation.

For facial paralysis and facial cosmetic treatments

Face and neck treatments require a small-diameter electrode (25-30 mm) because the muscles are small, and there is limited space, making it impossible to place larger electrodes with sufficient spacing.

I recommend using the 32mm ValueTrode Round or the 25mm PALS Round electrodes for the face.

For paralysed (paralysed muscle) treatments

The damaged nerve is sensitive. The better quality the electrode you use, the gentler you are on the nerve. So it’s worth using PALS or UltraStim electrodes.

Depending on the muscle you want to treat, you can use 25-32mm round electrodes (e.g. facial nerve palsy) or 5×5 and 5x9cm (peroneal palsy), etc.

For muscle stimulation treatments

For muscle stimulation, there are two guidelines as to what size electrode to use. Some recommend electrodes with a larger surface area, while others recommend electrodes of different sizes.

Those who advocate larger size argue that the larger the electrode, the easier it is to distribute the current in the muscles, the higher the comfort level, the higher the current intensity and the stronger the muscle contraction.

Advocates of different sizes suggest placing the smaller electrode on the most prominent part of the muscle belly. The smaller electrode concentrates more current on the motor nerve plate, situated at the center of the muscle. Some also believe that this permits it to penetrate deeper regions of the muscle before encountering another nearby electrode.

I recommend trying both variations and deciding which you feel is more effective based on your experience.

You can increase the life of your self-adhesive TENS electrode pin with careful use

You can reuse the electrodes that accompany your device for approximately 20-30 treatments, varying in their quality. There comes a time when they stop sticking, dry out and no longer transmit the pulse properly. At this point, you will need to buy a new electrode, which, if you use the device frequently, will mean recurring expenditure.

• Peel the electrodes carefully from the plastic sheet they come with.
• Do not touch the glue as this will reduce its adhesion.
• Do not stick it to clothing as dirt will quickly impair adhesion.
• Prior to applying the electrode to your skin, cleanse the treatment area with lukewarm, soapy water to remove any grease, and then thoroughly dry it. Only apply the electrode to completely dry skin.
• After use, peel it off your skin in one motion and immediately stick it back on the plastic sheet for storage. Do not pull by the cord, as the cord may tear!
• Keep the electrode in the fridge. Not in a freezer. This will increase the lifetime.
• If the surface of the electrode is dry, add 1 drop of water to the electrode to get a few extra uses.
• A dry electrode will fail to transmit the pulse, resulting in a diminished or lost treatment effect.

By considering and applying the above, you can maximize both the lifespan of your electrodes and the effectiveness of your treatment, while also optimizing your costs.

Is the self-adhesive TENS electrode replaceable?

You can also use “permanent” electrodes if you want to avoid repeated costs. These are manufactured typically from rubber, carbon, and silicone materials, making them nearly indestructible and allowing for years of use. They are non-sticky and non-gelled. They require rubber tape with Velcro or a separate adhesive tape (e.g. leuco-plast) to hold them in place. You cannot use these “dry”; you must apply a contact gel to transfer the impulse to your skin (without gel, the treatment will cause burning and stinging).

• Choose a specially designed large-surface electrode for treating your belly-bottom-comb (FastPads, Flexible Electrode)
• Simplify the treatment of your waist and abdominal muscles with an electrotherapy belt (FastBand Belt, UltraStim Belt)
• For muscle stimulation, you can use silicone carbon electrodes
• Electrodes that can be inserted into the vagina or anus can be used for treating incontinence.
• Iontophoresis uses a sponge-covered carbon electrode.