Abstract: A product for use in treating a subject, incorporating a light-conversion medium which receives ambient light of broad spectrum, and emits light at one or more peak wavelengths or ranges of wavelengths (?1, ?2, ?3) having greater intensity than corresponding intensity in the received broad spectrum ambient light. The products outlined are specifically designed for skin treatments of many different kinds, where the wavelengths chosen to have therapeutic or enhancing effects to the biological processes that occur inside or that directly affect the skin. The products can either exist as a unique treatment or be coupled with existing treatments in order to achieve an improved or differentiating result.