Bitter orange
Bitter orange, Citrus aurantium, is a sour citrus fruit whose peel contains the alkaloid synephrine.
Also listed as P-synephrine, Citrus Aurantium, Synephrine, Citrus aurantium
Blood pressure deserves attention
In the meta-analysis, longer use increased systolic and diastolic blood pressure. Reports of heart attacks, strokes and abnormal rhythms also exist, although the frequent use of multi-ingredient products means those reports cannot establish that bitter orange caused them. 1 2
A familiar plant name does not guarantee a predictable product
FDA testing summarized by NCCIH found substantial discrepancies between stated and measured synephrine amounts in supplements. NCCIH recommends discussing supplement use with a health professional, particularly when medicines are involved. 2
Caffeine changes the risk
BfR warns that caffeine and synephrine can reinforce each other’s effects on heart rate and blood pressure. Its assessment considers pharmacologically active combination products unsuitable for people with high blood pressure or other cardiovascular disease, and for children, pregnant women and breastfeeding women. 3
For information, not individual medical advice. Ingredient studies do not establish the effectiveness of these products.