In our deep dive into creatine, you find people talking about creatine causing kidney damage. Again, for those with no attention span or time, the answer is NO creatine does not cause kidney damage when taken in the recommended doses in healthy individuals with normal kidney function to start.
Creatine is degraded naturally by skeletal muscle to creatinine, which is carried in the blood and excreted through the kidneys in your urine. Healthy kidneys will filter the creatinine. Creatinine level in the blood varies with your muscle mass, so you see higher creatinine levels in men than women. It is also related to dietary creatine (found in meat) and creatinine intake. If your creatinine levels in your blood are high, it could be an indicator of poor kidney function.
You will find higher levels of creatine and creatinine in those who are supplementing. Studies have shown those on creatine supplements had no increase in serum (blood) creatinine, with others showing an increase that stayed within normal range. Only two studies were found that showed an increase over normal limits.
So why the hype?
It comes down to a case report published in 1998 of a young man with kidney disease. He had kidney disease for 8 years. He then started creatine supplements 15 g/day loading, then 2 g/ day for 7 weeks. His kidney health was thought to deteriorate because he showed higher levels of blood creatinine, so he stopped supplements. They ignored:
- Blood and urine creatinine levels increase when you eat meat or creatine supplements.
- two investigations showed creatine supplementation did not negatively impact renal function
- The dosage of creatine during the maintenance phase was only slightly higher than the daily creatine intake of a typical omnivore’s protein intake.
- two separate teams of experts in creatine metabolism wrote letters to the editor of Lancet
After this, there were small, poorly done studies which supported this claim. (Patients already with kidney disease, 100x dosages of creatine, etc). This compounded the hype.
Currently conservative estimates are that 8% of athletes supplement with creatine. Given the decades and thousands of individuals who have been on creatine, if kidney function were an issue, we should see it by now. We do not. This does not mean it could not happen. You need to be healthy, have normal kidney function, and take the recommended dosages.
In our research, one metanalysis of the data concluded “Today, after > 20 years of research which demonstrates no adverse effects from recommended dosages of creatine supplements on kidney health, unfortunately, this concern persists. While the origin is unknown, the connection between creatine supplementation and kidney damage/renal dysfunction could be traced back to two things: a poor understanding of creatine and creatinine metabolism and a case study published in 1998.”
Original study CREATINE
