Low-level light therapy uses low incidence levels of photon energy to target tissue to achieve a clinically useful effect without resulting in unintended heat or damage. It has shown dramatic beneficial effects when used for wound healing, pain management, and skin rejuvenation, but it has been slow to receive clinical acceptance. Lasers are more widely used for these types of treatments, but they can cause thermal injury and require a trained operator. Based on an extensive review of the therapy’s risks and benefits, the Forever Healthy Foundation supports the use of LED low-level light therapy as a valid treatment option for skin rejuvenation. According to our analysis, combination therapy using 633-nm (red) and 830-nm (infrared) LED light provides the greatest number of benefits to the skin, because red and infrared light have varying effects on different tissue components. Low-level light therapy works by inducing a cascade of intermediate reactions (signal transduction and amplification) that lead to the creation of adenosine triphosphate, the main energy source of the cell. The absorbance of red light causes a response that is primarily photochemical, with the main photoreceptor being cytochrome c oxidase. This photoreceptor has an action spectrum from 580 to 700 nm that peaks at 630 to 635 nm. Exposure to infrared light at 830 nm induces a different initial response that is photophysical in nature — meaning vibrational and rotational changes in the electrons of the atoms in the molecules that make up the membranes of the cells — and activates membrane transport mechanisms and cellular exchange. The energy requirements for this are high, so the mitochondria are recruited in the system to create adenosine triphosphate. We look forward to the development of more standardized protocols and a wider acceptance of low-level light therapy within clinical medicine. Both processes lead to a photoactivated cell that then has three possible modes of action: repair, functional improvement, or cell recruitment. Interestingly, low-level light therapy has been shown to have a particularly strong effect on cells that are functioning suboptimally. A series of light therapy treatments leads to a reduction in periocular and perioral wrinkling, increased production of collagen, and improvements in skin texture and firmness. Importantly, the side effects of low-level light therapy are minor — most commonly, only a transient erythema that clears within hours. In the scientific literature, the best results have been achieved with a nine-session protocol over one month — six sessions with infrared light and three with red light. The benefits of low-level light therapy require an extended period of time to develop and, therefore, up to a four-month follow-up period may be necessary to assess the full effect of a treatment series. The main types of devices currently in use are LED-based systems and filtered polychromatic lamps. LED systems are superior because of their quasi-monochromatic beams (which allow for precise chromophore targeting) and the flexibility of mounting them in arrays (which allows for hands-free operation and adjustment to the contours of the surface being treated). The Forever Healthy Foundation refrains from recommending a specific device manufacturer because it is likely that any high-quality device that uses the right protocol would have similar results. The evidence in favor of using low-level light therapy to treat a wide variety of conditions continues to mount, as corroborated by the several hundred articles that have been published within the last year. We look forward to the development of more standardized protocols and a wider acceptance of low-level light therapy within clinical medicine. Meet the author Cari Green, M.D., is the chief medical officer of the Forever Healthy Foundation and leads the Rejuvenation Now and Maximizing Health initiatives. She has long-standing expertise as a health consultant with clients in North America, Europe, and the Middle East. Green currently holds a license to practice medicine in Germany and Croatia, as well as full General Medical Council (GMC) registration in the U.K. In addition to her training in conventional medicine, Green has completed training in integrative/functional medicine, as well as several manual and movement therapies, including Rolfing, St. John Neuromuscular Therapy, Stott Pilates, Corrective Holistic Exercise Kinesiology, and the Gyrotonic and Gyrokinesis methods. The views expressed in ‘Biopinion’ are solely those of the author and do not necessarily represent those of Photonics Media. To submit a Biopinion, send a few sentences outlining the proposed topic to doug.farmer@photonics.com. Accepted submissions will be reviewed and edited for clarity, accuracy, length, and conformity to Photonics Media style.