[crazygringo]

Replicate the natural processes? It's literally just UV light.

UV comes in an huge variety of strengths outdoors.

There are no calculations to be a "bit off". It's just strong UV. You're making it sound a lot more complicated than it is.

[CAP_NET_ADMIN]

Sun also emits infrared which seems to cause positive effects counteracting some of the UV related problems.

[crazygringo]

Some cell and animal studies show that there is a slight possible effect. It hasn't been shown in humans, and even in extrapolation from animals, the protective benefit does not seem particularly significant.

[whycome]

Yeah. There are so many variables already. From angle to time of year to skin pigment to duration