Oranges are packed with vitamin C. High amounts of vitamin C suppress the production of the hormone cortisone. Cortisones ultimately decrease your testosterone levels, putting your body into a catabolic state, meaning that your body starts burning muscle for fuel. Vitamin C also increases your ability to combat diseases and colds. When you take creatine with orange juice, the insulin spike created by drinking orange juice, will increase your body's ability to store the creatine in the muscles. I think creatine is absolutely brutal, you can really feel the extra pump in the gym! It also gives the juice a nice sugary texture. Best use fresh oranges to make your juice, you can also use orange juice from the grocery store.