The cheapest and most popular form of creatine (and the sort used extensively in scientific studies) is creatine monohydrate, a white powder sports supplement that needs to be mixed with water/fruit juice etc before use. More recently, other more exotic and expensive forms of creatine have appeared, which claim to offer performance benefits over standard creatine. One of these is ‘creatine serum’, a liquid form of creatine that is claimed to offer a number of other advantages over powdered creatine, including instant absorption, no side effects (such as water retention, bloating or cramping) and complete assimilation into the muscles.

To test this theory, Californian researchers examined the effects of ingesting creatine serum on cross-country runners. All the runners underwent baseline testing by completing a 5,000m outdoor run followed by a VO2max test on the treadmill the same day. The runners were then split into two groups; 13 took the manufacturer’s recommended dose of 5mls of serum (2.5g of creatine), while the control group took an inert placebo.

As well as VO2max, heart rates, run times and perceived rates of exertion were recorded. The results showed that runners taking the serum had a significantly lower perceived rate of exertion and also managed longer durations on the incremental VO2max test. However, the actual VO2max figures were not significantly different between serum and placebo groups, and there was also no improvement in 5,000m run time in the serum group.

The scientists went on to conclude that ‘their data did not support the ergogenic claims of creatine serum in its current form and dose’.

J Strength Cond Res 2005; 19(4):730-4