The phrase "set formula" refers to a fixed and specific way of doing something or solving a problem. It means that there is a pre-established procedure or rule that you need to follow. Full definition
What sets this formula apart from other vitamins for older dogs are the unique herbal extracts that provide benefits not found in ordinary supplements. (holisticpetinfo.com)
What sets this formula apart from typical commercial dog foods is the fact that it is organic. (dogfoodinsider.com)