I used to work as a chemist and worked in nutritional chemistry for over 7 years. I've tested products like vitamin water. By the time you get that product to your house, most of the vitamins are likely depleted and way less than what they say on the label. All the C & B vitamins are extremely temperature, light and oxygen sensitive. Liquid products are more sensitive than solid products.

When we test stuff like this, it is in the most ideal conditions - shipped immediately to us right after it is made, it is placed in a container to not allow light in and it is placed in the refrigerator. They are also tested under special yellow lights so we don't deplete the vitamin content as fast. Vitamin C is tested immediately because it the most sensitive.

I personally would not spend the money on vitamin water unless you are drinking it because you like the taste. And I wouldn't trust the label on the product as it was produced in the absolute best conditions that don't really mimic the actual product life cycle that a typical consumer experiences.