Sunlight direct on the retina either without any obstructions or only through eyelids loads an enzyme necessary for serotonin production. The required amount of

Sunlight direct on the retina either without any obstructions or only through eyelids loads an enzyme necessary for serotonin production. The required amount of sunlight on the retina to reduce depression is 3 or more 20-30 minute sessions. It is actually harder than it might seem to get that much every week.