Creatine is something of a rarity in the world of sports nutrition because it does precisely what it says on the tin, which explains its enormous popularity with elite and recreational athletes alike. But, while studies have indicated that short-term creatine use (ie for a matter of days or weeks) is perfectly safe, almost no research has been conducted into the safety of long-term continuous supplementation over a period of months or even longer – a usage pattern that is far from rare.

Now this gap has been filled by new research that suggests long-term creatine users have nothing to fear. In this study, 175 patients with a neuro-degenerative disease known as amyotrophic lateral sclerosis, which results in damage to motor neurones in the brain and spinal chord, were randomly assigned to receive either 10 grams of creatine monohydrate per day or a placebo for a period of 310 days. (Previous studies on animals had indicated that extra creatine could offer some protection against the progression of this disease.)

Patients were regularly asked about any adverse effects of treatment, while the researchers carried out regular urine tests to pick up any effects on kidney function – the theory being that the kidneys would be particularly vulnerable to any potential harmful effects of long-term creatine use.

Analysis of the results showed no significant differences in adverse effects at any time between the treatment and control groups. And, although there was a slight increase in water retention in the limbs of the creatine group, the urine tests showed that there was no between-groups difference in kidney function. Given that the patients taking creatine were ingesting 10g per day (three times the dose needed by athletes to maintain muscle creatine saturation), the clear implication of this study is that long-term creatine supplementation presents little or no health risk to athletes!

Int J Sports Med 2005; 26(4): 307-13

Andrew Hamilton