Possible Rare Negative Effects of Creatine
The negative effects of creatine are only possible side-effects that may or may not occur in individuals using creatine.
Current studies indicate that short-term creatine supplementation in healthy individuals is safe. A number of small-scale, longer-term studies have been done and seem to demonstrate its safety.
However, in some instances there have been reports of muscle cramping with the use of creatine, though a study showed no reports of muscle cramping in subjects taking creatine-containing supplements during various exercise training conditions in trained and untrained endurance athletes. The cause of the reported cramping by some users may be due to dehydration, and extra water intake is vital when supplementing with creatine.
Other possible side effects include lower leg pain and may be associated with the use of creatine. Creatine may be the cause of an increase in the anterior pressures of the lower leg. This is usually found in post-creatine use when at rest and after exercise. Normal at-rest pressures have been found to be highly elevated by subjects who used creatine within the prior 35 days when compared to no supplementation.
This can produce an extreme amount of pain in the lower leg due to the rigidity of the anterior compartment of the lower leg and lack of fluid drainage out of the compartment. It may also be exacerbated by the increase of water content in the muscle fibers, putting more pressure on the anterior compartment. If the levels remain high for a long period of time, irreversible damage to tissue may occur, particularly to the peroneal nerve.
In addition, experiments have shown that creatine supplementation led to a rise in allergic lung reactions in an animal test on mice with pre-existent allergic disease.
Creatine supplementation, in the dosages commonly used, results in urinary concentrations that are 90 times greater than normal. The long term effects of this have not been investigated, but there is possibility for a variety of nephrotoxic, i.e., kidney damaging, events.
There is potential for direct toxicity on renal tubules where urine is formed, and for acceleration of kidney stone formation.
Creatine has been shown to accelerate the growth of cysts in rats with Polycystic Kidney Disease (PKD). Studies have not yet determined if Creatine supplementation will accelerate the growth of cysts in humans with PKD. PKD is prevalent in approximately 1 in 1000 people and may not be detectable until affected individuals reach their thirties.
Overall, the above side effects are possible but not highly probable which means the negative effects of creatine do not occur often. Nevertheless, it is always good to be informed.
The bottom line is that creatine has been around for a long time (since 1992) and athletes, bodybuilders and fitness enthusiasts have used creatine over the years to help them achieve better results with strength and muscle gain. If the side-effects were common and prevalent, creatine would have failed as a product in the open market long ago.
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