…special brightness-detecting cells that project and communicate directly with the hypothalamus and other parts of the brain that affect your hormones, energy, and emotions.

These are interesting cells. For those of us who learned that the retina has two kinds of light sensing cells, rods, and cones (yeah, me too), there is a third one: the ganglia are light sensitive, and those are what we’re talking about here. Evolutionarily, they’re pretty directly connected to the ‘light sensing spots’ in more primitive animals — and are connected to our more primitive control systems (e.g. iris dilatation, melatonin production). Those rods and cones probably started out as more specialized ganglia.

That said, I have a BIL who lives in the PNW (particularly dark and gloomy winters), who has seasonal issues. His solution: 6500K (AKA ‘daylight’) LED bulbs all through the house, other than the bedrooms. He says it works for him. Personally, I find the light a bit unnatural, but I’m guessing that those bulbs are not 90+ CRI (a measure of the ‘notchiness’ of the frequency emitted — higher number is smoother) and, as a photographer, the color shifts were my issue. A quick search on amazon for “A19 LED 6500K CRI90” seems to bear this out. BTW, A19 is the most common bulb base in the US, also called “medium”.