Why does your TENS unit sting?

Answer 1

Tens pads work best when moist and sticky. Pads that are not moist enough will produce a weak and stinging sensation. Conduction can be improved and stinging reduced somewhat by simply dipping your finger into some clear water and rubbing the water onto the massage pads. There are electrolyte solutions sold that claim to improve conductivity and reduce stinging.

The pads should be applied immediately to your skin when they are still wet. Make sure that the pads are making full and firm contact with the skin.

Some sites recommend storing pads in air-tight environment to retain moisture. I suggest refrigerating or even freezing the stored pads to prevent microbial growth which is enhanced by dark, warm, wet conditions. Alternatively, small Oxygen Absorber packets are available for pennies at LDS Distribution Centres and other food storage suppliers, and will totally stop microbial growth in an air-tight container, without freezing.

Worn out pads may also cause a stinging sensation, and marketing sites recommend replacing them after a month or so. What the term "worn out" means is unclear. I suspect it means dried out. Sticky replacement pads are widely available.