Red light therapy is sometimes used as a treatment for acne, possibly by reducing inflammation and sebum production.[1] However, most of the research on this topic is not very high-quality (often lacking appropriate control groups, for example).[2][3][4][5][6]
Some research suggests red light therapy can increase the dermal synthesis of collagen and elastin,[7][8] proteins that help maintain skin elasticity and which tend to decrease during aging. Consistent with this, a few clinical trials suggest red light therapy can indeed reduce the appearance of wrinkles,[9] although only a few studies exist, so more research is needed.
Finally, it’s been suggested that red light exposure may make the skin less susceptible to sunburns. The evidence for this draws largely from a single pilot study involving 15 people. In that study, regularly exposing the skin to red light — specifically a wavelength of 660 nm at an intensity of 60 mW/cm2 for 160 seconds — seemed to result in less erythema (redness) in response to UV exposure (although statistical significance was not examined).[10] Subsequent (unpublished) data from the same researcher indicated that this protective effect was greater with near-infrared light than red light. Ultimately, given the preliminary nature of this data, this finding requires replication. And even if red/near-infrared light does in fact have a sunburn-inhibiting effect, it can’t yet be assumed this translates into a reduction in UV-induced DNA damage, meaning that whether red light therapy reduces the risk of skin cancer is unclear.