creatine makes your muscles get big, but doesn't increase your strength. If you're going to the beach, take creatine. If beating your friends in bicep comparisons gives you boners, take creatine. Otherwise, CREATINE IS GARBAGE.
Take some protein if you really want to gain muscle mass. Otherwise, eat a healthy, balanced diet. Take a multi-vite to keep yourself healthy and balance inadequacies in what you eat. Get lots of sleep. Men's fitness recommends your body weight in grams of protein daily if you're doing lots of muscle work, but you can probably get away with quite a bit less.
although test show that in efforts longer then a minute creatine has little benefit...
in high intensity efforts of 5 to 20 seconds creatine helps the ATP system which is the primary fuel source for those efforts. especially in repetitive efforts...
not unlike the first portion of DH race or the work load of DS or Mountaincross.