Pre-workout supplements (PWS) claim to improve strength and reduce fatigue while training. Many of these products rely on the stimulant properties of caffeine (often in large doses) to produce this performance enhancement, yet a verification of the caffeine content of these products has never been conducted – until now.
In a study, led by Associate Professor Ben Desbrow from Griffith University’s School of Allied Health Sciences and published in Drug Testing and Analysis, 15 popular PWS were independently assessed for their caffeine content. Results indicated that the caffeine contained within these products differed considerably from the product label, and that approximately half of the investigated PWS products may expose consumers to potential caffeine related harms.
"We tested the caffeine content both within and between batches of the same product. Our values ranged from approximately 90 to almost 400 mg in one serve of some pre-workout products," says Associate Professor Desbrow.
A wide variation of caffeine content
"We found a wide variation of caffeine content, suggesting that consumers have the potential to be exposed to large and potentially dangerous doses of the stimulant."
Public health recommendations for caffeine (Adults: single doses less than 200 mg and daily consumption less than 400 mg, Adolescents: less than 3mg·kg-1 of bodyweight·day-1 in younger individuals (e.g. less than 185mg·day-1 for the average (62kg) 16 year male), reflect concerns over the increased availability of caffeinated products and increases in the frequency of caffeine related adverse events (including sleeping disturbance, anxiety, cardiovascular events, seizures and death).
The PWS data was also compared to manufacturer reported values via the product information panels.
"We found that product labels either did not state the caffeine content or did not provide consumers with an accurate estimate of likely caffeine dose. At present, it is challenging for any individual to ensure they ingest safe and effective ergogenic dose of caffeine when taking a PWS."
Associate Professor Desbrow says it is clear that the presence and severity of any potential side effects will relate to product choice and consumer eating patterns.
"The real concern comes when people take multiple doses of these products. This should be discouraged, as it is clearly not required from a sports performance perspective and may pose health risks.
"We need behaviourial studies to determine the frequency with which consumers risk exposure to excessive caffeine intakes from these products."
