Creatine Side Effects and Safety

My regular readers/subscribers know creatine monohydrate is one of the few supplements I believe in (see also: Does Creatine Work?).  I’ve been using it for years without any problems, and the extensive body of research speaks to the efficacy and safety of this supplement.

Let’s first talk about safety.  One of the concerns I hear about is possible kidney problems, but I don’t see why this would be an issue for those without any preexisting disease.  The Journal of the International Society of Sports Nutrition recently published a randomized, double-blind, placebo-controlled studied done on trainees who were also eating a high protein diet.  Subjects were randomly chosen to either take creatine monohydrate (a loading phase of 20 grams a day for five days, followed by maintenance of five grams a day) or a placebo.  Researchers found so significant differences in kidney function between groups after 12 weeks.1

Now let’s talk about side effects.  The two I hear about most often are gastric issues (stomach upset, etc.) and bloating.  I’ll address both:

I think the simplest solution to avoid any gastric issues is to buy micronized creatine and use warm water to dissolve it before you drink it.   I believe most people have problems because they try to drink this supplement undissolved.  Here’s the issue: creatine doesn’t dissolve very quickly in cool liquids.  Water and other liquids are likely to pass through with undissolved creatine still sitting around in your guts. The body will attempt to solubilize (dissolve) substances like creatine that remain in the digestive tract in powder/granular form.    This is often accomplished by drawing fluids out of the cells inside the digestive organs.  As you can imagine, this isn’t likely to feel good.

creatinemonohydrateNow to the bloating issue.  Creatine causes fluid retention in the muscles, so I’m a little skeptical when it comes to claims of bloating.  I believe this problem is normally the result of inferior formulas that contain sodium and sugar.  It could also be the result of a horrible diet (blame the supplement, not the pizza).  I’m not aware of any research to back up the claims of “bloating.” One study, in fact, found that creatine use did not affect fluid distribution.2

There’s one more thing I should mention in this discussion.  Some unscrupulous supplement companies will try to hype up these supposed side effects of creatine because they are trying to market some “new improved” formula.  Don’t fall for it.


1. JISSN 2013, 10:26 doi:10.1186/1550-2783-10-26 Does long-term creatine supplementation impair kidney function in resistance-trained individuals consuming a high-protein diet?

2. J Athl Train. 2003 Mar;38(1):44-50. Creatine Supplementation Increases Total Body Water Without Altering Fluid Distribution.

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