Craig Pickering and John Kiely from the University of Central Lancashire in the UK highlighted the different doses recommended for caffeine in scientific literature so far in in their paper, published this summer in the journal Nutrition.
They also proposed some methodological recommendations for researchers to consider if they wish to conduct low-dose caffeine research in the future.
“At present, it is not clear whether the ergogenic [stamina and performance] benefits of a lower dose of caffeine are the same as more standard doses, which may have important implications for athletes seeking to harness caffeine's ergogenic effects,” they argued
For example, the International Society of Sports Nutrition’s position on caffeine published in 2010 that the researchers cited summarizes that caffeine is effective at enhancing performance at ‘moderate dosages’ (around 3 to 6 mg/kg) around an hour before performance, while another study from 2014 suggests that even lower doses may have ergogenic benefits.
“Such an examination is crucial, as athletes are likely interested in whether their caffeine dose offers the maximal ergogenic benefits, as opposed to just an ergogenic effect,” they wrote.
Filling the gap: Trials that compare dosages
According to the two researchers, clinical trials that directly compare low caffeine doses with those falling into line with the currently accepted optimal dose instead of a placebo are required.
“Such research would remove much of the existing ambiguity permeating caffeine research,” they argued.
“It is not sufficient to demonstrate that a new intervention is more effective than placebo, but that it produces better results than the currently accepted best treatment.”
Do you still get benefits if you regularly drink caffeine?
There is also debate regarding the effects of regular caffeine consumption, with some studies finding a negative effect of habituation, while other reporting none.
However, they noticed that the doses used in the studies varied. “What if the dose of caffeine used was within the currently accepted guidelines, as opposed to <3 mg/kg? As this was not explored, the answer remains unclear,” they wrote.
“This is not an attack on the authors, who were exploring a different research question, but it nevertheless underscores the point that increasingly robust conclusions could be inferred from caffeine research if the currently accepted optimal dose was included.”
Published online ahead of print, https://doi.org/10.1016/j.nut.2019.06.016
‘Are low doses of caffeine as ergogenic as higher doses? A critical review highlighting the need for comparison with current best practice in caffeine research’
Authors: Craig Pickering, BSc; John Kiely MSc