While many companies don’t like to come out and tell you directly, this formula is derived from primarily the skin of cows, and sometimes uses the bone and muscles as well. For users that feel uncomfortable with this fact, there are also vegan options out there on the market that use ingredients such as green tea that is rich in vitamin C. For the companies that use animal products, we were drawn to companies that make a point to express that the cows used for their product were free range, grass fed, and antibiotic free. We want users to feel good about the supplements that they are taking, and the efforts that went into ensuring that they are healthy, natural, and humane.