Science-based guides on sunlight, circadian health, and photobiology.
Your skin's UV protection resets every winter. Rebuilding it before summer's peak intensity is a process — and skipping it is how most sunburns happen.
Twice a year, the planet delivers twelve hours of light and twelve of dark — the photoperiod our species evolved under. What that baseline reveals about how we live now.
Everything you need to know about producing vitamin D from sunlight — how UV index, skin type, time of day, and location all affect how much sun you actually need.
The ancient cross-quarter day of Imbolc marks a biological threshold that modern science is only beginning to understand. Your body already knows the light is coming back.
Modern indoor environments deliver the wrong light at the wrong time, and hold the temperature steady year-round. The health consequences are measurable, and the fixes are simpler than you think.
UVB disappears at high latitudes for months. But the morning sun is still doing critical work — and most people are missing it entirely.
The longest night of the year isn't a problem to solve. It's a biological signal your body has been waiting for — and modern life is drowning it out.