A method for treating skin tissues, the skin tissues defining an epidermal layer and a sub-epidermal layer, the epidermal layer defining a skin surface and the sub-epidermal layer extending from the epidermal layer substantially opposite to the skin surface, the method comprising: positioning a radiation source outside of the skin tissues at a predetermined distance from the skin surface powering the radiation source so as to produce infrared radiation having a predetermined spectrum and a predetermined power and irradiating the sub-epidermal layer with the infrared radiation through the epidermal layer, the predetermined spectrum and the predetermined power being such that the infrared radiation is absorbed to a larger degree in the sub-epidermal layer than in the epidermal layer.
