Does creatine monohydrate cause kidney damage and lead to renal dysfunction?
The International Society of Sports Nutrition (ISSN) released a landmark statement in 2017 in a top-tier SCI journal in the field of sports nutrition, jointly with 10 leading experts in sports medicine. Based on over 1,000 studies and billions of dosage data points, the statement concluded that creatine monohydrate is the safest and most effective sports nutrition supplement to date, with no age restrictions, and even holds medical potential for individuals with health conditions.
However, confusion surrounding this essential supplement persists. This article draws on numerous research findings, particularly focusing on the ISSN's peer-reviewed article addressing common questions and misconceptions, as well as its stance, and compares reviews of various forms of creatine.
1. Does creatine damage the kidneys and cause kidney dysfunction?
Concerns that creatine supplements may cause kidney damage or kidney dysfunction remain one of the most persistent and harmful misconceptions in the field of sports nutrition. This misconception may lead many people to abandon the use of safe and effective supplements due to unfounded fears.
The origin of the kidney damage myth This widespread concern likely stems from two main causes: Confusion about creatine metabolism: Creatine and its metabolite creatinine are filtered by the kidneys and excreted through urine. Since elevated blood creatinine levels are a marker of kidney dysfunction, some people mistakenly believe that creatine supplements may place stress on or damage the kidneys.
2. A 1998 case study: The most influential source of this misconception may be a case report published in The Lancet, which involved a young man with kidney disease whose kidney function deteriorated significantly while taking creatine. Despite its significant limitations, this case report garnered widespread attention and helped solidify the misconception about kidney damage in the public consciousness.
Figure A illustrates the chemical process by which creatine naturally degrades into creatinine through cyclization, losing a water molecule.
Figure B shows the stability of creatine over time at different pH levels, indicating that creatine remains stable at neutral pH but degrades more rapidly in acidic environments.
This chemical reaction helps explain why claims of kidney damage are unfounded—the formation of creatinine is a natural metabolic process unrelated to kidney function.
What many people are unaware of is that this case study has serious flaws. The patient had been suffering from kidney disease for eight years and was undergoing treatment with a drug (cyclosporine) that may be nephrotoxic. The authors also overlooked the fact that creatine supplements naturally increase blood creatinine levels without affecting actual kidney function.
2、What exactly has science proven?
To address concerns about kidney health, numerous well-designed studies have specifically examined the effects of creatine on kidney function:
(1) Short-term studies: Multiple studies have found that creatine loading protocols (up to 20g/day) do not have adverse effects on kidney function.
(2) Long-term studies: Studies have examined the effects of creatine supplementation over periods ranging from months to years, and the results consistently indicate that creatine supplementation does not have harmful effects on kidney function in healthy individuals.
(3) Clinical populations: Even studies targeting patients with type 2 diabetes (a population at higher risk for kidney issues) found no adverse effects of creatine supplementation on kidney function.
The scientific consensus from multiple systematic reviews and meta-analyses is clear: supplementing with creatine at recommended doses does not adversely affect kidney function in individuals with healthy kidneys.
The comprehensive table above summarizes eight comparative studies that examined the effects of creatine on hydration and thermoregulation in different populations and exercise conditions. Consistent results across different study designs indicate that creatine does not impair hydration or increase heat stress. Several studies actually demonstrated beneficial effects, providing strong evidence to refute the notion that creatine causes dehydration or cramping.
After nearly three decades of research, including numerous randomized controlled trials specifically examining kidney function, there is substantial evidence indicating that supplementing with creatine at recommended dosage regimens does not impair kidney function in healthy individuals.
If anything, this misconception serves as a case study illustrating how a flawed case report can generate enduring misunderstandings that contradict the weight of scientific evidence.
Simply because creatine's metabolite is creatinine, and creatinine is used as a kidney function biomarker, does not imply a connection between creatine use and kidney function.
