MaxiShop doesn't list any possible side effects of its muscle-growth supplement Maxinutrition Cyclone, formerly known as Maximuscle Cyclone. But high doses of its two major ingredients have been known to cause muscle cramping, diarrhea and nausea, according to WebMD.
MaxiShop states the product is well-tested and considered safe when taken in accordance with the instructions. The manufacturer lists whey protein and creatine as some of the main components of Maxinutrition Cyclone.
WebMD.com mentions several side effects of both creatine and whey protein and disputes the effectiveness of the two supplements for muscle building. Creatine in high doses can cause muscle cramping, diarrhea and, in some people, irregular heartbeat. An overdose of whey protein can lead to nausea and cramps. Whey protein can cause an allergic reaction in anyone with milk and dairy allergies.
There is some controversy surrounding supplements that claim to help build muscle, states WebMD. Creatine does not actually build muscle, WebMD states. Instead, it causes water retention in the muscles, which gives the appearance of larger muscles. Not enough research on creatine has been done to determine who can benefit from taking it. Furthermore, WebMD notes that skeletal muscle only holds a certain amount of creatine at a time and that adding more won't raise levels in the body.