Why don't doctors always recommend creatine?

One of the main reasons doctors hesitate is a laboratory value: creatine supplementation slightly raises blood creatinine levels, by an average of around 0.07 µmol/L. Creatinine is the standard marker doctors use to estimate kidney function. A rise in it therefore quickly raises suspicion. But that suspicion is unfounded: actual kidney function, measured as the glomerular filtration rate, did not change significantly. The rise in creatinine is a normal by-product of increased muscular creatine turnover, not a sign of kidney damage. This is shown by a systematic review with meta-analysis¹.

Another persistent misconception is that creatine accelerates hair loss through a rise in the hormone dihydrotestosterone (DHT). In a 12-week randomised study of 38 healthy young men (5 grams of creatine per day), no differences were found in DHT, the DHT-to-testosterone ratio, or hair growth parameters compared with placebo². There is therefore no evidence that creatine promotes baldness.

What creatine does do is well documented. Combined with resistance training, it produces on average well over 1 kg of additional lean mass compared with training without creatine, and body fat percentage also falls modestly but measurably (average -0.88%). This was demonstrated in a meta-analysis of 12 studies³. Without training the effects are much smaller, although creatine may still offer some muscle preservation, for example during recovery after surgery⁴.

A broad international expert panel concluded that creatine monohydrate is safe for healthy people of all ages. The persistent misconceptions about kidney and liver damage are not scientifically supported⁴. Whether you take it before or after training probably makes little difference; there are weak indications that post-training intake is slightly more favourable, but the evidence for this is too limited for a firm recommendation⁵.