Vitamin C is one of the water soluble vitamins. Anything the body doesn't use will be excreted in the urine. So it's a waste of money to feed extra but in most cases it won't hurt.

You have to be more careful about fat soluble vitamins (A, D, E, K) which will be stored in fat and can get to toxic levels.

You also have to be careful about minerals. It's not only the amount of certain minerals but the balance between them that is important. Toxicity could easily be a problem as well as deficiency.

The dog food companies spend a lot of money on nutritionists and testing to ensure that all of the above are in balance. If you have better information than they do - by all means use your information!

Thank you Nancy.
I knew about the other vitamin's that you have to be careful. That is why I asked why do you need to be careful when supplementing with vitamin C.

I use sodium ascorbate isn't the Vit C coupled with another ingredient like calcium or something?

Are you thinking of Ester C....not the same as vitamin C