Herb library · Herb · Citrus aurantium
Bitter orange
A sour orange used in marmalade and flavorings, and sold in supplements for weight loss and sports performance, often as an ephedra replacement. It has not been clearly shown to help any health purpose, and serious heart events have been reported with products containing it.
Serious warning
Serious medical events, including abnormal heart rhythms, heart attacks and strokes, have been reported in people who took bitter orange products, though most contained several ingredients, so bitter orange's role is unclear. FDA researchers who tested 59 bitter orange supplements found six adulterated with synthetic stimulants that are not legal in dietary supplements (NCCIH).
Traditional use
Native to Southeast Asia. The fruit is too sour to eat raw, but the fruit, peel and essential oil are used in cooking, to flavor beer and spirits, and in perfume. The fruit contains p-synephrine, a chemical structurally similar to ephedrine; bitter orange products became more popular after the FDA banned ephedra, and were promoted as ephedra alternatives. The oil is used on the skin and in aromatherapy.
What studies show
- Limited
Weight: the effects are unclear. Studies were small, usually tested combination products rather than bitter orange alone, and had conflicting results.
- Limited· shows no benefit
Athletic performance: several small studies, with or without caffeine, gave inconsistent results, and most showed no benefit.
- Insufficient
Fungal skin infections (ringworm, athlete's foot, jock itch): the one study of bitter orange oil had no comparison group, so its results are hard to interpret.
- Insufficient
Anxiety and sleep (aromatherapy): it is unclear whether bitter orange oil helps.
Be careful of
Cautions
- NoteLikely safe in the amounts found in food. The oil is generally well tolerated on the skin and in aromatherapy.
- ConditionStudies disagree on whether it raises blood pressure and heart rate. Of 23 supplements whose labels stated a synephrine amount, only 5 contained close to that amount.
- NoteThe NCAA lists synephrine (bitter orange) as a banned stimulant, which matters for college athletes.
- PregnancyIt may not be safe during pregnancy or breastfeeding, and animal data suggest substances in it might reduce milk production.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“Orangettes (petit grains) are the unripe fruits which drop from the trees, and are considerably used on the continent under the name of orange berries.”
Sources
- Bitter Orange: Usefulness and Safety (opens in a new tab) · NCCIH · read September 25, 2026
Reviewed September 25, 2026.