) Ester-C is a highly concentrated and readily available form of vitamin C recognized as a key anti-oxidant. Use as a dietary supplement in horses with conditions associated with degenerative joint disease, pulmonary infections, and stress related conditions. Contains 14 grams Ester-C per scoop. Feed 5-7 grams twice daily during high levels of stress or working conditions. Feed 5-7 grams daily for maintenance. Powder.