Crazy Nutrition’s Ultimate CRN-5 is the best creatine formula available on the market as it is a science-based formula that will suit individuals having clumsy digestion. Most creatine powders cause incessant digestive issues to fitness lovers as they start to experience symptoms like causing stomach discomfort like bloating, gas, stomach upset, headaches, abdominal cramps and stomach cramps and even muscle cramps after consuming any normal creatine formula.