The synephrine in bitter oranges is thought to work as a sympathetic adrenergic agonist, stimulating receptors involved in the “fight or flight” response. These effects stimulate the cardiovascular system resulting in increased heart rate and blood pressure. Also, these effects may stimulate metabolism, resting metabolic rate and lipolysis (breakdown of fat). Appetite may also be suppressed via slowed movement of food through the gastrointestinal tract.[1] [2]
How does bitter orange work?
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•Last Updated: May 16, 2025
Bitter orange contains synephrine, which acts as a sympathetic adrenergic agonist; it stimulates the cardiovascular system and potentially increases heart rate, blood pressure, and metabolism. It may also suppress appetite by slowing food movement through the gastrointestinal tract.