The 10-week study, published in the Journal of Nutrition and Metabolic Insights, compared Jack3D users with those consuming a placebo. Both control and intervention groups were told to consume the supplements 30 minutes before exercise work outs on selected days.
“Our data indicate that a dietary supplement containing 1,3-dimethylamylamine (DMAA) does not significantly increase resting heart rate or blood pressure (although systolic blood pressure increased ∼6 mmHg with the supplement),” wrote the researchers from the University of Memphis.
“Moreover, the supplement does not adversely impact bloodborne biomarkers of health,but rather, results in a decrease in LDL-C [cholesterol].”
The randomised, double blind study was sponsored by USP Labs, the manufacturer of Jack3D, which in addition to DMAA, contains caffeine, creatine monohydrate, alanine, schinzandrol A, and arginine alpha-ketoglutarate.
The authors noted that the rise in systolic blood pressure meant, “those with elevated blood pressure to avoid use of dietary supplements containing 1,3-dimethylamylamine.”
They also called for further study with bigger study groups.
Of the cholesterol reduction, they noted: “The supplement results in a small decrease in LDL-C, which may suggest a potential cardioprotective role. While this may have clinical relevance, additional studies inclusive of larger samples are needed to replicate these findings, as well as to extend and expand upon other findings associated with this work.”
USP Labs’ joined the researchers in observing that the studies were, “consistent with previous 2-week and 8-week studies which found no significant increase in blood pressure or liver and kidney function following chronic use of DMAA & DMAA-containing supplements.”
Jack3D and other pre-workout supplements have been deemed an unauthorised drug in the UK and Canada due to the presence of DMAA, but they are sold widely in other countries and the internet.
DMAA has been linked to deaths in the US military, is the subject of at least two class actions in the US and is under investigation by authorities in several European countries.
Source: Journal of Nutrition and Metabolic Insights
February 2012. doi: 10.4137/NMI.S8885
‘Impact of a Dietary Supplement Containing 1,3-Dimethylamylamine on Blood Pressure and Bloodborne Markers of Health: a 10-Week Intervention Study’
Authors : Paul N. Whitehead, Brian K. Schilling, Tyler M. Farney and Richard J. Bloomer