Formulated for horses of all ages, Cox Vet Lab Acti-Flex Joint Liquid Horse Supplement can aid in your horse’s ability to produce synovial fluid. Synovial fluid is a lubricating substance that helps your equine friend repair damage and strengthen joints. If you’re the pet parent to a performance horse, the Cox Vet Lab Acti-Flex Joint Liquid Horse Supplement, made from ingredients such as tree gum resin and Boswellia serrata, may be just what he needs to support healthy joint function.