Abstract: An apparatus for relief of chronic and acute pain in tissue or arthritic joints and/or for promoting wound healing and human tissue growth can include a handheld housing supporting an array of light emitting diodes (LED) for application of light to a portion of a human body. The LED array can have a light output in a wavelength range of between approximately 630 nanometers to approximately 940 nanometers, inclusive, and a power intensity in a range of at least approximately 20 milliwatts per square centimeter. A control interface can be include buttons for controlling operation of the LED array, and a timer operable in response to pressing the buttons for delivering power to the LED array for a predetermined period of time. The control interface can include an over-temperature sensor operable to automatically turn off power delivery to the LED array when a sensed temperature is above a predetermined value.