I give my dogs 1,000 mg of Vitamin C every day. Both have done great with it. Vitamin C is Vitamin C....no matter if it is dogs or humans. There is only ONE vitamin C/ascorbic acid. Glucosamine Chondroitin..I get from the human isle. The pet Glucosamine/chondrointin is more expensive. Altough I do like Cosaquin/Dasaquin.