Of course, there will be some side effects, but not very big. However, long-term large-scale use will increase the burden on organs such as liver and kidney. It is best to find professionals to guide the use of such supplements. If you want to gain weight healthily, you should start with diet and exercise. Just make sure that your calorie consumption is less than your income.

It should also be noted that muscle tension, stiffness or spasm are easy to occur after drinking creatine. It should be taken with grape juice or other sugary drinks (except fructose), because the increase of insulin concentration caused by sugar can accelerate the absorption of creatine in water by muscle cells.

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In the past 10 years, creatine monohydrate has been regarded as one of the most popular and effective nutritional supplements, and its status is high enough to keep pace with protein products and rank among the "best-selling supplements". It is rated as a "must-use" product for bodybuilders, and it is also widely used by athletes in other sports, such as football and basketball players, who want to improve their energy level and strength. Creatine is not a prohibited drug, it naturally exists in many foods, so any sports organization can't help using creatine.

References:

Creatine monohydrate _ Baidu Encyclopedia