The effect of an herbal dietary supplement containing ephedrine and caffeine on oxygen consumption in humans.

OBJECTIVE

To determine if an herbal dietary supplement for weight loss increases metabolism.

DESIGN

Measurement of peak oxygen consumption in response to the supplement followed by a double-blind placebo-controlled crossover measurement of oxygen consumption in response to the supplement.

SETTING

The study was conducted in an academic research clinic.

SUBJECTS

Ten obese females (aged 41 +/- 4 years [body mass index (BMI)] 33.3 +/- 2.6 kg/m2) participated in the peak oxygen consumption test; six of these females participated in the crossover trial.

INTERVENTIONS AND OUTCOME MEASURES

Peak oxygen consumption was measured for 45 minutes after taking two herbal dietary supplement capsules orally, each containing the equivalent of 10 mg of caffeine and 5 mg of ephedrine. The crossover trial measured oxygen consumption for 45 minutes after taking two herbal dietary supplement capsules or two placebo capsules orally.

RESULTS

The herbal dietary supplement increased peak oxygen consumption 0.178 +/- 0.03 (SEM) kcal/min (8.01 +/- 1.35 kcal/min expressed over 45 minutes) above baseline (p < 0.0001), and 2.0 +/- 0.56 kcal/min over 45 minutes compared to placebo (p < 0.006).

CONCLUSIONS

The herbal dietary supplement increased oxygen consumption when taken according to the package directions. The significance of this rise for weight loss requires further research.