Bitter Orange (Synephrine)
Bitter Orange, containing p-synephrine, is a stimulant that increases metabolic rate and lipolysis, often used for weight management and fat loss. It is considered to have a lower cardiovascular impact compared to ephedrine.
Evidence last reviewed: 20 Apr 2026
Research indicates that p-synephrine can enhance resting energy expenditure and fat oxidation during rest and exercise. While the evidence is moderate to high, more long-term studies are needed to fully understand its effects and safety profile.
Weight lossAdults seeking weight management · Meta-analysisHigh
The meta-analysis found that p-synephrine can promote weight loss with minimal cardiovascular side effects.
Resting energy expenditureAdults · RCTModerate
Acute ingestion of p-synephrine increased resting energy expenditure.
Cardiovascular safetyHealthy subjects · RCTModerate
A single dose of bitter orange extract did not prolong QTc interval or cause significant hemodynamic effects.
Fat oxidation during exerciseHealthy active women · RCTModerate
p-Synephrine increased fat oxidation rate during exercise of increasing intensity.
Fat oxidation at restAdults · RCTModerate
p-Synephrine increased fat oxidation at rest.
Forms & usage▾
Take 100-200 mg of p-synephrine before meals or workouts, ideally in capsule form.