Supplements that tend to
increase metabolic rate
are relatively weak by themselves, but may exert potent effects
when taken together. A recent study examined the thermogenic effects of a supplement formula taken for 7 days in
overweight men. The formula contained low doses of capsaicin (225 mg), green tea extract
(750 mg), Caffeine
(609 mg), and calcium (1965 mg). These supplements all work to stimulate the sympathetic nervous system
through different mechanisms. After seven days of treatment with either the active supplement or placebo, subjects
spent 24 hours in a respiratory chamber during which time detailed measurements of energy expenditure were measured.
This is the most sensitive and accurate procedure for measuring energy expenditure in people over several hours.
Compared to the placebo condition, the supplement formula resulted in an average increase in energy expenditure of
approximately 40 kcal per day with no side effects. The authors speculate that even more impressive results would
be likely if higher doses were used.
Belza A, Jessen AB. Bioactive food stimulants of sympathetic activity: effect on 24-h energy expenditure and fat oxidation. Eur J Clin Nutr. 1-9, 2005.