Not Medical Advice:
C4 Extreme, advertised as "the most explosive pre-workout intensifier", contains creatine nitrate. As its name suggests, it's a creatine bonded to a molecule of nitrate (NO3).
Sol Orwell of SimplyShredded.com says:
When creatine supplementation is ceased, it takes anywhere from a few weeks to a month for creatine levels in the body to normalize to pre-supplementation levels.
The variance in how long it takes to clear the body depends on how much you exercise (more exercise accelerating the rate of normalization) and how much creatine was initially stored in muscle tissue.
Although supplementation of creatine does acutely suppress your body’s production of creatine (suppresses the rate limiting enzyme), creatine production is restored within a day or two after stopping creatine.
According to MuscleandStrength.com, when you take creatine, it stays in your blood stream for about 1.5 hours. Taking creatine 1 hour before your workout gives your body time to absorb the creatine and 1.5 hours for you to use it.
Discover the key myths and facts you need to know about creatine, shared by Men's Health.
Learn 5 Best Bodybuilding Programs To Pack On Serious Muscle from BodyBuilding.com.