Low-level laser (light) therapy (LLLT) is a fast-growing technology used to treat a multitude of conditions that require stimulation of healing, relief of pain and inflammation, and restoration of function. Although the skin is the organ that is naturally exposed to light more than any other organ, it still responds well to red and near-infrared wavelengths. The photons are absorbed by mitochondrial chromophores in skin cells. Consequently, electron transport, adenosine triphosphate (ATP) nitric oxide release, blood flow, reactive oxygen species increase, and diverse signaling pathways get activated. Stem cells can be activated allowing increased tissue repair and healing. In dermatology, LLLT has beneficial effects on wrinkles, acne scars, hypertrophic scars, and healing of burns. LLLT can reduce UV damage both as a treatment and as a prophylaxis. In pigmentary disorders such as vitiligo, LLLT can increase pigmentation by stimulating melanocyte proliferation and reduce depigmentation by inhibiting autoimmunity. Inflammatory diseases such as psoriasis and acne can also benefit. The non-invasive nature and almost complete absence of side-effects encourage further testing in dermatology.
Increasingly, non-invasive therapies for skin disease and skin rejuvenation are used, especially in Western countries where relatively high disposable incomes are combined with the desire for an ideal appearance fostered by societal pressures. Although the skin is the organ that is naturally most exposed to light, it still responds well to red and near-infrared wavelengths delivered at the correct parameters with therapeutic intent. Low-level laser therapy (LLLT) was discovered in the late 1960s, but only in recent times has it been widely applied in dermatology. The introduction of light-emitting diode (LED) devices has reduced many of the concerns formerly associated with lasers, such as expense, safety concerns, and the need for trained personnel to operate them. In fact, many LED devices are designed for home use and are widely sold on the internet. This review will cover the use of LLLT as possibly the ultimate non-invasive approach to treating the skin.
LLLT, phototherapy, or photobiomodulation refers to the use of photons at a non-thermal irradiance to alter biological activity. LLLT uses either coherent light sources (lasers) or non-coherent light sources consisting of filtered lamps or light-emitting diodes (LED) or, on occasion, a combination of both. The main medical applications of LLLT are reducing pain and inflammation, augmenting tissue repair and promoting regeneration of different tissues and nerves, and preventing tissue damage in situations where it is likely to occur. In the last few decades, non-ablative laser therapies have been used increasingly for the aesthetic treatment of fine wrinkles, photoaged skin, and scars, a process known as photorejuvenation. More recently, this approach has also been used for inflammatory acne LLLT involves exposing cells or tissue to low levels of red and near-infrared (NIR) light. This process is referred to as ‘low-level’ because the energy or power densities employed are low compared to other forms of laser therapy such as ablation, cutting, and thermally coagulating tissue. Recently, medical treatment with LLLT at various intensities has been found to stimulate or inhibit an assortment of cellular processes.