Many weight loss formulas are using bitter orange because it is similar in structure to the common stimulant ephedra, which is banned by the FDA. Because bitter orange is also a mild stimulant, there is concern it may have adverse effects on heart function and blood pressure.
Researchers investigated the acute effects of a single dose of a commercially available bitter orange product containing 27 mg of active ingredient. There were no differences in measures of heart activity or blood pressure for 8 hours after ingestion of the supplement compared to placebo.