It’s known that LED is a semiconductor diode that emits light when an electric current is applied in the forward direction of the device, as in the simple LED circuit.

The red LEDs do this by altering the interactions between water and elastic proteins in the skin. In a new study, Andrei Sommer and Dan Zhu of the University of Ulm in Germany found how water molecules in the skin interact with different substances. They found that water molecules close to a hydrophobic, or "water-hating", substance formed a slippery crystalline layer, and those surrounding a hydrophilic, or water-loving, substance were glue-like.

Elastin, the fibrous protein that gives skin its elasticity and prevents wrinkling is hydrophobic. However, with age, fatty acids, amino acids and calcium salts build up on the elastin fibres, and make them hydrophilic. It makes the water film around the fibres increasingly glue-like, which makes them to stick to the surrounding tissue and reduce their elasticity. It has earlier been confirmed that red light with a wavelength of around 670 nanometres can render more mobility to the water molecules close to hydrophilic substances.

Thus, the researchers aimed powerful red LEDs at the skin around the eyes for 90 seconds daily for 10 months. They observed a significant reduction in wrinkles after applying red LEDs.

"The result was rejuvenated skin," New Scientist quoted Sommer, as saying. Such LEDs have also been used earlier for reversing eye damage and promote wound healing.