Bitter Orange
Also known as: Seville orange, Seville oranges
As a culinary fruit/peel, bitter orange is safe and has long traditional use (e.g., marmalade). However, concentrated bitter orange extracts containing synephrine, particularly when combined with caffeine, have been associated with cardiovascular adverse events; FDA and NIH ODS caution about supplement use.
What it is
Citrus aurantium (bitter/Seville orange) — fruit and peel used as flavoring and source of synephrine in supplements.
Flavoring (peel/zest in marmalades, liqueurs); supplement ingredient (extracts standardized for synephrine).
Why it's flagged
- Concentrated synephrine extracts (especially with caffeine) are linked to cardiovascular adverse events in supplement use
- Furanocoumarins may cause CYP3A4 drug interactions at high intake
What regulators actually say
"Bitter orange... contains synephrine and other compounds. Use of bitter orange supplements has been linked to strokes, heart attacks and other serious cardiovascular issues, especially when combined with caffeine."
"EFSA evaluated the safety of synephrine in food supplements... combined intake of synephrine with caffeine raises concerns about cardiovascular effects."
Regulatory status
United States — FDA
Bitter orange peel oil and extract GRAS as flavorings under 21 CFR 182.20; supplement extracts are not GRAS at high concentrations.
European Union — EFSA
Permitted as flavoring; EFSA has reviewed synephrine in food supplements.
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