The vitamins are already synthetic anyway, as they're manufactured, so they're already dead anyway
I imagine you can't really do any damage to them though.
Also, as for chemistry, the change is merely physical, not chemical. NO new substances are formed at an ionic level and no checmical bonds are borken. The solution is just a mixture. So no, the hot water won't
mutate the drink either
Also, it's probably not to wise having these too often, as you should probably get some
real food into you so your stomach can work on it and break it down. Although i don't have any evidence or anything to back this up? just an observation.
Although, as long as it tastes alright hot, then drink up
