Many individuals who exercise with the goal of gaining weight look towards workout supplements to improve their performance and hasten their progress. Protein powder and creatine are two common supplements that are readily available and have proven benefits. The effects of protein powder are fairly straightforward – it provides more protein with which muscles can rebuild and repair, thus reducing muscle soreness and improving recovery time. Creatine, however, is slightly more controversial regarding possible adverse effects. Many reports of side effects, however, come from the use of creatine supplements that have contaminants in them, and pure creatine is, in fact, a safe and effective workout supplement.
Creatine is naturally produced in the body from glycine and arginine, two amino acids. It helps replenish stores of adenosine triphosphate (ATP) – the primary molecule that our cells use as energy. In muscle contraction, ATP is necessary for cross-bridge cycling. Specifically, ATP binding to myosin is what causes myosin to release the actin filament. ATP is then hydrolyzed to adenosine diphosphate (ADP) and an inorganic phosphate molecule, and myosin rebinds to actin in a high-energy configuration in preparation for contraction. The take away from this mechanism being that if ATP stores are depleted during exercise, muscles will no longer contract properly. Creatine, synthesized in the liver and kidneys, travels to skeletal muscle where a creatine kinase phosphorylates it. Phosphocreatine is the actual molecule that enhances ATP regeneration.
Some literature indicates that excess use of creatine supplements can reduce the ability for the body to naturally synthesize it. Other studies have found no negative effects in the liver, kidneys, muscles, or heart after prolonged creatine supplementation. The main documented cases of adverse side effects have been due to people using creatine supplements with levels of contaminants that exceeded the established safe levels. In contrast, pure creatine seems to be safe, provided it is used within the proper dosage ranges. So for everybody planning on hitting the gym before summer, creatine is certainly not necessary for a successful workout routine, but it is safe as long as it’s pure.
Okay, so I know this is anecdotal but I’ve known 2 guys who used creatine supplements and it caused behavioral side effects: increased irritability and increased aggression. Side effects disappeared after they stopped taking creatine. Is this a thing? Has creatine use been linked to aggression in the studies you’ve read?