In 1998, a single case report helped create one of the most persistent myths in sports nutrition.
The paper, published in The Lancet, described a 25-year-old patient who had been diagnosed with a serious kidney disease called glomerulosclerosis. During the period in which he was taking creatine supplements, his kidney health deteriorated. On the surface, the case seemed concerning. But there was an important detail: the patient already had pre-existing kidney disease.
The obvious conclusion should have been simple. People with kidney disease should approach dietary supplements with caution and consult their physician before taking them. That advice applies not only to creatine but to many supplements and medications. Instead, the narrative took a different direction.
Creatine itself began to be portrayed as dangerous. Some interpretations of the report even suggested that creatine supplementation could lead to severe health consequences.
The story spread quickly, and the perception stuck.
Soon after the case report appeared, creatine researcher Professor Paul Greenhaff responded with a rebuttal published in The Lancet. He pointed out that the conclusions drawn from a single case were not supported by broader scientific evidence.
Around the same time, several tragic deaths of American wrestlers were also incorrectly linked to creatine use.
Investigations later revealed a very different cause: extreme dehydration. The athletes had been attempting to rapidly lose weight in order to qualify for lower weight classes. Creatine had no established connection to the incidents.
But by then, the narrative had already taken hold.
In the years that followed, scientists began studying creatine more closely. And the results were remarkably consistent.
Study after study found that creatine supplementation at recommended doses does not harm kidney function in healthy individuals. In fact, creatine has become one of the most extensively researched ingredients in sports nutrition. A daily intake of around 3 grams per day is widely regarded as safe and is supported by decades of research.
Like many supplements, creatine can cause minor side effects if used improperly. Very high doses may lead to digestive discomfort or diarrhoea, particularly if fluid intake is too low. In those situations, dehydration may contribute to muscle cramps. However, these effects are typically associated with excessive intake, not normal supplementation. When creatine is taken in moderate amounts—or divided into smaller doses throughout the day—it is generally well tolerated.
More than two decades after that initial case report, the scientific evidence surrounding creatine is clear. Creatine supplementation is safe for healthy individuals when used at recommended doses. Yet the myth linking creatine to kidney damage continues to circulate.
This highlights an important reality in nutrition science: a single early report can shape public perception for years, even when later research provides much stronger evidence to the contrary.
Today, creatine remains one of the most trusted and well-supported ingredients in sports nutrition.
The science has moved forward. The conversation should too.
