Red light (the sun is made of 43%) shows promise in enhancing cognitive function, treating neurophysiological disorders, lowering blood glucose and insulin, supporting a healthy circadian rhythm, wound healing, hair growth, and collagen stimulation.

It's also super peaceful to be shrouded in red light.

A selection is listed below,  more options listed at EMR-Tek.

Interesting Studies:

• Red Light Optogenetics in Neuroscience HERE

• Red-Light-Activatable AND-Gated Antitumor Immunosuppressant

       (methylene blue sneaking into the discussion again) HERE

• Affect of light qualities on plant's circadian rythms HERE