I've enjoyed the Vitamin D articles. The one that has to be considered, though, is how Prevagen uses Vitamin D. They clain that Apoaequorin is the magic. But there are studies that show Vitamin D is the real benefit. Not comparitive as such, but the separate studies on each one leads to that conclusion. Beyond my pay grade to know for sure, but it sure seems like they are marketing their wrong infredient. hahaha