By Bryan Kernan the author of The Bodybuilding Supplements Guide
Creatine is undoubtedly the most well-studied of all bodybuilding supplements and, along with protein, it’s also the most popular. Everyone loves creatine because it works, and it is generally considered to be safe for most users. Any lifter who is interested in his health, though, needs to take a critical eye toward anything he puts in his body, so the continued whispers linking creatine to liver damage warrant a deeper look.
Ever since it hit the market in the mid 1990’s, creatine has been the target of innuendos regarding its long-term safety, and chief among the accusations is that it can cause liver damage, even though evidence has been hard to come by.
So what’s the real story? Is creatine completely safe, or can it cause liver damage?
Let’s take a look at the available information to get a better handle on this situation.
Most of the studies into the effectiveness of creatine have also included at least a cursory tracking of liver enzymes. Almost without exception, researchers in these cases have found no evidence that creatine negatively affects liver function.
A serious flaw of these types of studies, however, is that they are conducted over a relatively short time frame, usually 12 weeks or less.
So what about the long term?
In 2002, scientists at Truman State University published results of a multi-year study that examined the effects of daily creatine usage on a group of 23 college athletes for up to nearly six years. Blood tests showed no adverse effects on either kidney OR liver function.
Similarly, a 2001 study out of Appalachian State University found no evidence of negative side effects caused by creatine supplementation for a group of mixed-gender colleges athletes for up to four years.
On the other hand, a 2000 literature review by Belgian researchers found that changes in liver bio markers have occasionally been noted in conjunction with creatine usage, and that there have been multiple case studies indicating acute liver damage associated with creatine usage. While acknowledging these findings, the scientists from the Free University of Brussels maintained that no well-controlled study has shown a loss of liver function due to creatine usage.
Beyond the body of scientific literature, trusted sources of medical information are an important data point to consider when it comes to supplement safety.
The Mayo Clinic website, for example, lists a litany of negative side effects associated with creatine usage, including elevated liver enzymes and a loss of liver function. Though Mayo provides no specific references, the weight of their reputation gives these claims more legitimacy than if they came from a mainstream media outlet
While WebMD does not specifically point the finger at creatine for causing liver damage, they do recommend against using the the supplement for anyone who already suffers from liver problems. Creatine is produced naturally by the kidneys, liver, and pancreas, and taking in exogenous sources could conceivably impair the body’s own production if organ damage already exists.
Medline Plus, a website run by the National Institutes for Health (NIH), gives creatine a LIKELY SAFE rating for oral consumption of up to five years. On the other hand, high dosages are labeled as POSSIBLY UNSAFE, with liver function impairment high on the list of possible side effects.
So, Does Creatine Cause Liver Damage?
The vast majority of research results show no evidence that creatine supplements cause liver damage in healthy adults. Over the relatively short time frame of the studies, typically NO change in liver enzymes have been seen, and even long-term observations suggest that creatine is safe for most people.
Nevertheless, the few studies that indicate slight changes in liver enzymes or acute liver damage for specific individuals have been enough for several respected authorities to caution us about creatine’s possible negative side effects on the liver.
Because these are our bodies we’re talking about, and because we want to keep them healthy above anything else (including muscle growth), it’s always best to exercise caution with the substances we consume. That goes double for potent supplements that go beyond what we can get form our “normal” food, and especially when there are any questions around safety.
Before you start taking creatine, or any other supplement, talk to your doctor about the risks, and have him give you a complete physical, including blood work. If you decide to use creatine, make sure to get regular blood tests while you’re “on” and take careful notice of any changes in liver enzymes.
Creatine appears to be safe for most people, but you only get one body. Take care of it!