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Botanical illustration of Bitter Orange
MedicinalSourced entry

Bitter Orange

Citrus aurantium

Seville orange, a sour citrus whose fruit, peel and oils flavor food, drinks and perfume. It's sold in weight-loss supplements, but trials found no real weight loss and higher blood pressure.

Safety at a glance

Tap a box to read the safety notes below. “Nothing recorded” means our sources don't cover it, not that it's safe.

Bitter Orange may interact with some medicines. If you take any medicine, read Interactions with medicines below and talk to your doctor or pharmacist before using it.

What is Bitter Orange?

Plant family
Rutaceae, the citrus family
Parts used
The fruit, peel, flowers and leaves, and oils from them
Where it grows
Southeast Asia
Genus
Citrus
Species
aurantium

Also called

Seville Orange, Sour Orange

Traditional names

Zhi Shi

Traditionally used for

  • Flavoring
  • Aromatherapy
  • Sleeplessness (traditional)

Traditionally described as

  • Fruit contains p-synephrine

Health topics

Where Bitter Orange appears in symptom search, and why. Being listed doesn't mean it's a proven treatment.

  • Anxiety

    In small studies, breathing in bitter orange oil lowered anxiety before a medical test and during a stressful task. Whether aromatherapy with it helps is unclear.

  • Sleep Problems (Insomnia)

    The leaves are a folk remedy for sleeplessness. Not studied in people.

Traditions that use it

Natural compounds

p-Synephrine

Safety

Interactions with medicines

  • Seville orange juice can block CYP3A4, an enzyme in the gut that breaks down many medicines, similar to grapefruit juice. It has been shown to interact with felodipine, a blood pressure drug.[1]Study

Side effects

  • Taken over time, synephrine from bitter orange raised blood pressure by about 6 points (top number) and 4 points (bottom number) in a 2022 review of trials, and tended to raise heart rate.[2]Review or trial

  • Abnormal heart rhythms, heart attacks and strokes have been reported in people taking bitter orange supplements, though most products also contained other ingredients, so bitter orange's role is unclear. It's likely safe in the amounts found in food.[3]Health agency

Pregnancy

  • It may not be safe to use bitter orange supplements during pregnancy.[3]Health agency

Breastfeeding

  • It may not be safe to use bitter orange supplements while breastfeeding, and animal studies suggest substances in it might reduce milk supply.[3]Health agency

Contamination

  • When the FDA tested 59 bitter orange supplements, most didn't contain the amount of synephrine on the label, and 6 contained synthetic stimulants that aren't legal in supplements.[3]Health agency

Depends on how it's prepared

  • The NCAA bans synephrine (bitter orange) as a stimulant, so athletes who are drug tested should avoid bitter orange supplements.[3]Health agency

What does the research say?

Traditional use

These are traditional uses, not proven treatments.

  • The fruit is too sour to eat raw, but the fruit, peel and oils are used in cooking, to flavor beer and spirits, and in perfume. Bitter orange oil is used on the skin and in aromatherapy.[3]Health agency

  • The Basque people of Europe used the leaves for sleeplessness, stomach aches and a racing heart. In South America and Mexico the leaves are used as a laxative, for sleeplessness and to calm the nerves.[4]Study

Research in people

  • Bitter orange is sold in weight-loss and sports supplements, but it hasn't been clearly shown to help with any health problem. Studies of weight loss and athletic performance were small, mostly tested mixtures of ingredients, and had conflicting results.[3]Health agency

  • A 2022 review that pooled 18 placebo-controlled trials found that synephrine, the main active compound in bitter orange, didn't cause meaningful weight loss or change body fat when taken over time.[2]Review or trial

  • In small studies, breathing in bitter orange oil lowered anxiety in people having a bone marrow test, and in people withdrawing from crack cocaine during a stressful speaking task.[4]Study

In short

Supplements can raise blood pressure and heart rate; may interact with medicines.

Sources

  1. [1] Flavonoids and Furanocoumarins Involved in Drug Interactions · DOI: 10.3390/molecules30081676Peer-reviewed study
  2. [2] The Safety and Efficacy of Citrus aurantium (Bitter Orange) Extracts and p-Synephrine: A Systematic Review and Meta-Analysis · DOI: 10.3390/nu14194019Review or clinical trial
  3. [3] Bitter Orange: Usefulness and Safety — National Center for Complementary and Integrative Health (NCCIH), NIHGovernment health agency
  4. [4] Citrus aurantium L. Active Constituents, Biological Effects and Extraction Methods. An Updated Review · DOI: 10.3390/molecules26195832Peer-reviewed study

This information is educational and traditional in nature, and is not a substitute for professional medical advice. Unfamiliar word? See what these words mean.