What is the shelf life of various forms of Vitamin D?
I have found information on the interenet that states that Vitamin D has a very short shelf life after it is produced. What I mean by this is not the shelf life in the body but the shelf life of the tablets, capsules or liquid supplements in the cupboard :)
Some information I found states that vitamin D will oxidize quickly and once exposed to oxygen will be depleted in 3-4 weeks rendering the tablets or other forms of the supplement pretty much useless.
What research have you found and what do you know about this aspect of vitamin D?