NO SIDE EFFECTS WHEN USED FOR OVER FOUR YEARS!
Finally, a long-term study (albeit retrospective, i.e. data collected retrospectively) that looks at the possible long-term side effects of CREATINE as a nutritional supplement. Regarding the intake of creatine over several months or even several years, critical voices are repeatedly raised, warning against such long-term supplementation, since the substance has only been available as a nutritional supplement on a larger scale for about 10 years and therefore cannot yet be conclusively assessed. The present study indicates at least with up to 4 years of supplementation of CREATINE , all clear.
When examining Schilling et al. 26 athletes from various disciplines (athletics, weightlifting, American football) were questioned about the effects and possible side effects of supplementation, clinically examined and a total of 65 blood values, including hormones, were determined. Seven of the test subjects had no experience with creatine intake (control group), nine had been taking this nutritional supplement for almost a year and ten test subjects had already been using creatine in cycles for more than a year up to four years. The intake cycles typically lasted 4 weeks, followed by a 1-4 week break. The "loading dose" for the first week was an average of 13.7 g daily, the "maintenance dose" for the rest of the supplementation period was a comparatively high average of 9.7 g daily. At the time of the study, all creatine users were in the "maintenance phase".
All blood parameters determined in the test subjects were within the normal range , apart from two "outliers" in some enzyme parameters, which were found in all groups and did not suggest a connection with creatine supplementation. There were no statistically significant differences between the groups, except for the total protein content in the serum, which was slightly higher in the group that had been supplementing creatine for almost a year than in the other groups.
Likewise, the creatinine in the blood of creatine users was higher than that of non-users. This value, which was also just above the normal range in two athletes, represents the breakdown product of creatine in the body. Previous studies have already shown that in some cases when this supplement is taken, this parameter increases slightly without this representing a clinically relevant disorder. In addition, the available data show that such increases in creatinine are always reversible. It should also be noted that the creatinine level in the blood is also very dependent on the amount of muscle mass and that the long-term creatine users in this study also had a clearly higher fat-free body mass than the other subjects, so this could also be the reason for the higher values.
The hormonal parameters (including testosterone, growth hormone, cortisol) remained unchanged in all subjects after creatine intake.
A total of seven of the test subjects reported occasional muscle cramps as a side effect. However, this was mentioned most frequently by four of the seven athletes with no experience of creatine supplementation (corresponding to 57% compared to 11% and 20% in the two creatine groups respectively), so the claim that creatine leads to increased muscle cramps is not correct according to these data. All of the people affected in the creatine groups also added that they did not believe that the supplementation was responsible for this. Only three of all creatine users reported occasional gastrointestinal complaints (flatulence to mild diarrhea, the side effects typical of higher individual doses) during the loading phases as a clear side effect. 84% of all users rated creatine as an effective and performance-enhancing substance, and all of those surveyed wanted to continue using it.
What was also interesting in this study was that among creatine users lower blood levels of total cholesterol and triglycerides (neutral fats) were observed, supporting previous data showing a somewhat improved blood lipid profile with creatine supplementation.
This study has provided encouraging results regarding the safety of creatine over a long period of time, unlike so many previous studies with 4-8 weeks of supplementation or less. Of course, this does not mean that we can make a final judgment that creatine is 100% safe as a dietary supplement, but the existing results at least suggest that possible long-term side effects are not to be expected.