Agreed, there are several potential issues that make it difficult to say there's no downside. There's a difference between Vitamin D production and absorption.

Agreed, there are several potential issues that make it difficult to say there's no downside. There's a difference between Vitamin D production and absorption. Have we firmly established that it's better to absorb all via digestion? Moreover, tanning is due to an immune response. I can't speak to whether that in itself could have positive effects of the immune system, I would like to know more. While the cons may very well outweigh the pro (ie cancer & skin damage) not sure why the other isn't discussed in context of moderation.