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What is Bitter Orange?

Bitter Orange
Other Names: Chongcao, Citrus aurantium, Fructus aurantii, Green Orange, Kijitsu, Seville Orange, Sour Orange, Zhi Shi

Who is this for?

German Commission E of the German Federal Institute for Drugs and Medical Devices is the German governmental agency that evaluates the safety and effectiveness of herbal products. Commission E has approved bitter orange to treat stomach complaints that may be associated with low volumes of gastric acid and also to increase appetite. Currently, in the U.S., however, the main use of bitter orange is just the opposite--to encourage weight loss.

Since the withdrawal of ephedra (also known as ma huang), which was banned by the U.S. Food and Drug Administration (FDA) in April 2004, other natural products have been publicized as safer alternatives for weight loss. One of those products is bitter orange. The peel of bitter orange contains synephrine, octopamine, and other stimulant chemicals that may work in at least two ways to help individuals lose weight.

First, they are believed to increase thermogenesis, which is the production of heat within the body by processes such as exercise and the break down (metabolism) of food. Increasing thermogenesis "burns" more calories. Therefore, such products may be promoted as "fat burners". Secondly, chemicals in bitter orange may decrease appetite. Although no human studies have been done to determine how bitter orange may affect appetite, research with laboratory animals may show that aromatic chemicals in bitter orange affect parts of the brain involved in appetite control.

However, weight-loss claims for bitter orange or synephrine are based mainly on tradition with very little scientific evidence. Many of the laboratory animal studies of bitter orange used intravenous forms of synephrine that are not commercially available. In addition, animals often received much higher doses than are recommended for human use.

Even in smaller oral doses, bitter orange may have ephedra-like side effects because synephrine is similar in shape and possibly in activity to epinephrine, a chemical in ephedra. Because some of the chemicals in bitter orange may cause blood vessels to tighten, it may have effects on heart function. In fact, increases in heart rate, blood pressure, or both did occur for a significant number of individuals in some of the bitter orange studies.

Results from the very few controlled clinical studies that have been conducted to test the weight-loss effect of bitter orange in humans have been inconclusive. While some studies found an increase in thermogenesis among participants taking bitter orange, others found no weight-loss effect. Additionally, some of the studies used a combination product containing caffeine and St. John's wort as well as bitter orange.

The actual cause of any weight loss among participants in those studies is uncertain. Weight-reduction effects from bitter orange or any other dietary supplement may be only temporary, as well, with weight increasing after the supplement is stopped. Neither bitter orange nor synephrine increased energy levels or improved athletic performance for any of the participants in several small observational studies.

Results from the very few controlled clinical studies that have been conducted to test the weight-loss effect of bitter orange in humans have been inconclusive. While some studies did find an increase in thermogenesis among participants taking bitter orange, others found no weight-loss effect. Additionally, some of the studies used a combination product containing caffeine and St. John's wort as well as bitter orange.

The actual cause of any weight loss among participants in those studies is uncertain. Weight-reduction effects from bitter orange or any other dietary supplement may be only temporary, as well, with weight increasing after the supplement is stopped. Neither bitter orange nor synephrine increased energy levels or improved athletic performance for any of the participants in several small observational studies.

In laboratory studies and case reports, topical use of bitter orange oils has shown some antimicrobial effects. Although no controlled clinical studies prove these effects, bitter orange oils sometimes are applied to treat fungal infections such as athlete's foot. In some parts of the world, they may also be rubbed or sprayed onto foods to prevent spoiling by bacteria. Additionally, bitter orange oils may repel insects, such as mosquitoes.

When should I be careful taking it?
Up to 6% of a bitter orange product may consist of synephrine. Used as a drug in prescription and non-prescription products such as eye drops and nasal sprays, synephrine causes blood vessels to contract. Therefore, it may worsen heart disease and some types of glaucoma. Individuals with high blood pressure, other heart conditions, or narrow-angle glaucoma should not take bitter orange.

Taking the oils of bitter orange by mouth is discouraged because they may be aspirated (inhaled into the lungs), possibly causing lung damage.

Applying bitter orange oil to the skin may make the areas where it is applied more likely to sunburn when the skin is exposed to sunlight or to artificial light such as in sun tanning booths. Individuals who apply any of the bitter orange oils should be careful to avoid direct sunlight. Rarely, the same effect has been reported by individuals who took bitter orange by mouth.

What side effects should I watch for?
Major Side Effects:
Bitter orange contains stimulants such as synephrine, which is similar to some chemicals in ephedra (ma huang), a product that is now banned from the U.S. market after being associated with severe side effects. In general, stimulants raise blood pressure, body temperature, and heart rate. Isolated cases of strokes and heart problems such as worsened high blood pressure, heart rhythm disturbances, and heart attacks have occurred in individuals who were taking products containing synephrine or bitter orange--usually along with other ingredients, such as caffeine. Although Although the exact causes of the problems are not clear, synephrine is known to tighten the walls of blood vessels. individuals who have heart conditions or who have risk factors for heart disease or strokes should not use bitter orange.

Ephedrine, a substance similar to synephrine, is known to pass into breast milk and to cause changes in the heart rate and heart rhythm of breast-feeding infants. Ephedrine has been removed from the U.S. market and no similar reports have been attributed to the use of bitter orange, but women who are breast-feeding should discuss the use of bitter orange with a doctor before beginning to take it.

One case has been reported of an individual who experienced drastically reduced blood flow to the lining of the colon while taking a bitter orange product. The resulting inflammation healed after bitter orange was stopped.

Less Severe Side Effects:
More common side effects from oral forms of bitter orange are usually temporary. They include:


Topical bitter orange can make unprotected skin more sensitive to sunlight or artificial light such as is used in sun tanning parlors. Individuals who use bitter orange should be sure to use sunscreen, as well.

Contact with bitter orange oils may irritate the skin causing redness, itching, rash, swelling, or blistering.

What interactions should I watch for?
Prescription Drug:
If bitter orange is taken by mouth, it may increase the production of stomach acid, potentially interfering with Histamine-2 (H-2) receptor blockers and proton pump inhibitors.

H-2 receptor blockers include:

cimetidine (Tagamet)
famotidine (Pepcid)
nizatidine (Axid)
ranitidine (Zantac)

Proton pump inhibitors include:

omeprazole (Prilosec)
pantoprazole (Protonix)

Because it is a non-specific central nervous system (CNS) stimulant, bitter orange may increase the effects and the side effects of prescription drugs that also stimulate the CNS. Used mainly to treat attention-deficit hyperactivity disorder (ADHD), narcolepsy, and obesity; stimulant drugs can raise heart rate and blood pressure. They include:

amphetamine salts (Adderall)
dextroamphetamine (Dexedrine)
methylphenidate (Concerta, Methylin, Ritalin)
modafinil (Provigil)
phentermine (Adipex-P, Ionamin)

In experimental animals, bitter orange has increased blood levels of cyclosporine, a drug used mostly to prevent rejection after organ transplants. Blood levels of cyclosporine that are too high may cause facial redness, headaches, nausea, painful or bleeding gums, or increased sensitivity in the fingers and toes. Temporary kidney damage or liver damage may also result.

Dangerously high blood pressure may result if bitter orange is taken with a type of antidepressants called monoamine oxidase inhibitors (MAOIs), which include:

tranylcypromine (Parnate)
Rasagiline (Azilect) and selegiline (Eldepryl, Emsam, Zelapar), drugs used to treat Parkinson's disease, are related to the MAOI antidepressants. They also should not be taken with bitter orange.

Drugs known as psoralens cause the skin to be excessively sensitive to sunlight. Psoralens include methoxsalen (Oxsoralen or 8-MOP). In addition, some antibiotics such as ciprofloxacin (Cipro) and tetracycline may make the skin more likely to sunburn. If bitter orange is taken at the same time as a sun-sensitizing drug, the chance of sunburn increases.

Because it is broken down by certain enzymes in the liver, bitter orange may possibly interfere with the use of prescription drugs that are processed by the same enzymes. Some of these drugs are:

Allergy drugs such as fexofenadine Antifungal drugs such as itraconazole and ketoconazole Cancer drugs such as etoposide, paclitaxel, vinblastine, or vincristine Drugs for high cholesterol such as lovastatin midazolam.

Products containing bitter orange peel are not known to interfere with the effects of felodipine (Plendil), a prescription drug used to treat high blood pressure. However, drinking bitter orange juice when felodipine is taken has resulted in higher than expected levels of felodipine in the blood. The chance of side effects, such as confusion, dizziness, shortness of breath, and changes in heart rate, from felodipine may be increased.

Non-Prescription Drugs:
Dextromethorphan (abbreviated as DM or DXM) is an anti-coughing ingredient in many non-prescription cough and cold products such as Nyquil and Robitussin DM. Taking bitter orange and DM together has been associated with blood levels of DM that are higher than expected. As a result, the risk of side effects, such as drowsiness, fatigue, nausea, stomachache, and vomiting, may increase. Very large amounts of DM in the blood may cause confusion, excitement, hallucinations, impaired judgment, slowed breathing, slurred speech, excessive sweating, vision changes, and the inability to coordinate muscle movements. For children, large DM overdoses have lead to seizures, coma, and (rarely) death.

Stimulants, such as pseudoephedrine (PSE) or phenylephrine (PE), may be included in non-prescription drugs that are used for increasing energy, losing weight, raising mental alertness, or treating colds or asthma. If bitter orange is taken by mouth at the same time as a product containing PSE or PE is being used, the central nervous system (CNS) may be over stimulated, possibly resulting in physical symptoms such as insomnia, and emotional symptoms such as irritability. Increased blood pressure is also possible. Individuals who are not sure whether the non-prescription drugs they take contain stimulants should ask a doctor or pharmacist before beginning to take bitter orange.

The possibility that bitter orange can increase the production of stomach acid could interfere with the effectiveness of antacids and over-the-counter medications such as Pepcid AC, Prilosec OTC, and Zantac AR.

Herbal Products:
Certain herbal products are CNS stimulants that may result in side effects if they are taken with bitter orange. These herbal products include ephedra, guarana, mate, and Panax ginseng. Ephedra was taken off of the market in 2004. It should not be taken orally for any reason. Taken together with bitter orange, ephedra or any other stimulant herbal may increase the risk of insomnia, irritability, nervousness, and other side effects.

Caffeine increases the CNS-stimulation effect of bitter orange. Although many commercial products contain both bitter orange and caffeine, the combination may cause excessive nervousness and irritability, along with other signs of over-stimulation. Large quantities of caffeinated beverages such as coffee, soft drinks, and tea should not be consumed when taking bitter orange.

Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how bitter orange interacts with drugs, other herbals, and foods and the severity of those interactions.

Should I take it?
Several different varieties of bitter orange trees grow as evergreens, which generally reach 18 feet to 20 feet in height. Although bitter orange trees are less likely to develop diseases than most other types of citrus plants, they need a warm, sunny climate. Believed to be native to tropical areas of southeastern Asia, bitter orange is now cultivated in India, Mediterranean countries, South America, the southwestern United States, and the islands of the Caribbean.

The trees produce fragrant, white flowers in late spring and early summer. The fruits develop in late summer and fall. When they are ripe, bitter oranges are slightly smaller than the sweet oranges usually found in U.S. markets. Both their peels and pulp are a darker red-orange color; their peels are more wrinkled; and their pulp and juice are more sour. Bitter oranges are popular for cooking in Europe--for example, they are common ingredients in European marmalade and sauces for meats. Bitter oranges are also eaten raw and squeezed for juice.

The flowers, juice, peel, and volatile oils of the bitter orange are all used commercially. Volatile oils (also called essential oils) possess the characteristic smell and taste of the plant. They usually evaporate quickly at room temperature. in addition to oil from the peelings of ripe fruits, bitter orange produces three other widely used oils:

Bergamot oil from the unripe peel is used to flavor candy and Earl Gray tea
Neroli oil distilled from the flowers is used in bath oils and skin care products
Petitgrain oil that comes from buds and leaves is used for making candles and soap

All four bitter orange oils are included in aromatherapy, massage oils, and perfume. Aromatherapy is the use of fragrances to affect mood. Distilling the flowers of the bitter orange also produces orange flower water, which is used as a flavoring and as a base for topical pharmaceuticals and skin care products. The U.S. Food and Drug Administration does not evaluate herbal products, but it has recognized bitter orange flowers, oils, and peel in small amounts as flavoring agents. Dried bitter orange peel is a common flavoring for drugs, foods, sodas, and alcoholic beverages such as Grand Marnier and Triple Sec.

In the traditional medicine of Asia, Europe, and South America; the flowers, fruits, leaves, and peels of bitter orange have been used to treat a number of conditions including insomnia and gastrointestinal (GI) complaints such as indigestion and diarrhea. Chemicals in bitter orange are antispasmodic, which means that they can relax tight muscles to help relieve stomach cramps. In homeopathy, bitter orange flowers and peel are used to relieve pain. For Western medicine, the peel of the bitter orange is used most.

After being separated from the spongy white layer just beneath the skin, the peelings are dried. They may be used to brew tea or powdered and made into capsules, extracts, or tablets. Extracts are concentrated liquid preparations usually made by soaking chopped or mashed plant parts in a liquid such as alcohol, and then straining out the solid parts.

Dosage and Administration:
For treating dyspepsia (indigestion) or lack of appetite, the German Commission E recommends a total daily dose of 4,000 mg (4 grams) to 6,000 mg (6 grams) of dried bitter orange peel made into tea and divided into three doses a day. Bitter orange tea is made by soaking its dried peel in 15 ounces to 18 ounces of boiling water for 10 minutes to 15 minutes. The solid bits of bitter orange peel are strained out. Because of its strong and unpleasant taste, the tea usually is sweetened or flavored before drinking.

For weight loss, recommended oral doses for commercially available forms of bitter orange (primarily capsules or tablets) differ greatly. Weight loss remedies usually contain bitter orange extract in combination with other herbs and supplements. A common recommendation is to take a product containing 100 mg to 150 mg of bitter orange two times or three times a day. Bitter orange products standardized to 4% alkaloids (mainly synephrine) provide about 32 mg of synephrine per day.

Standardization by the manufacturer should assure the same amount of active ingredient in every batch of the commercial preparation. Standardization of herbal products is not required by the U.S. Food and Drug Administration (FDA), so not every product sold in the United States will contain the same amounts of active ingredients. In addition, the content of bitter orange products may vary depending on the type of bitter oranges that were used, where they grew, what the weather conditions were, what time of year the oranges were harvested, how they were processed, and where they were stored.

Pure bitter orange oil pressed from the peels of ripe fruits is available for topical use, and three other oils derived from bitter orange--bergamot oil (from the peel of green bitter oranges), neroli oil (from its flowers), and petitgraine oil (from the leaves and young branches)--may also be applied directly to the skin. They all are used widely as bath oils or massage oils, as well. In studies, any of the pure bitter orange oils has been applied daily for up to 3 weeks.

Orally, bitter orange is used for weight loss in the United States, but in Europe and other parts of the world, it is used to treat stomach conditions. Topically, bitter orange may have some effect against bacteria, fungi, and other infective organisms.

Because it may cause blood vessels to tighten, bitter orange may worsen some types of glaucoma, heart conditions, and high blood pressure. The synephrine in bitter orange may cause irritability and sleep problems for infants whose breast-feeding mothers take bitter orange orally.

Side Effects:
A few very serious side effects, such as heart attacks or strokes, have occurred while bitter orange was being taken. More commonly, it is associated with milder side effects such as dizziness, headaches, and nausea. Bitter orange may make sunburn more likely if applied to the skin.

Bitter orange can interfere with:

Cold or allergy products that contain phenylephrine or pseudoephedrine
CNS-stimulating drugs or herbals
Drugs that lower stomach acid
Monoamine oxidase inhibitors (MAOIs), rasagiline, selegiline
Psoralens and other drugs that sensitize the skin to sunlight.

Solaray's Bitter Orange Extract

Gaia Herbs Liquid Phyto Diet Slim

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