Red light therapy (RLT) is a treatment that uses low-level red light to stimulate cell regeneration and blood flow. It's also known as low-level laser therapy (LLLT) or photobiomodulation (PBM). 
RLT is thought to work by: Increasing collagen production, Increasing fibroblast production, Increasing blood circulation to tissue, and Reducing inflammation in cells. 

RLT can be used to treat a variety of conditions, including: 
Skin: Improves skin appearance, reduces wrinkles, and treats skin conditions like eczema and psoriasis
Pain: Relieves pain and inflammation, including pain from cancer treatment side effects
Muscles: Increases endurance and tones muscles
Brain: Improves cognition and immune function
Nerves: Repairs nerves and relieves pain
Bones, tendons, and wounds: Promotes healing
Hair: Increases hair growth
Fat: May reduce body fat in some areas

RLT uses a lamp, device, or laser that emits red light with a wavelength between 630 to 700 nanometers.

The light penetrates the skin and is absorbed by mitochondria, which then produce more energy to help cells repair themselves.

RLT uses very low levels of heat and doesn't expose the skin to UV rays.