There are no known permanent, undesirable side effects to TES. There are some transient side effects. The incorrect placement of electrodes can actually increase spasticity. Stimulating at an intensity that is too high can result in muscle aches. These side effects will subside within a few days of stopping the treatments. Rarely, there have been reports of skin irritation from the electrodes. Skin irritation is more likely to occur if the individual has a sunburn or skin lesion (such as chicken pox). It is recommended that treatment be suspended while such lesions heal.