Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

Bitter Orange Ingredients & Drug Interactions

by Pure Herbs

Bitter Orange label
See full label image
Liquid Category: Botanical
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Bitter Orange against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Bitter Orange is a dietary supplement by Pure Herbs with 1 active ingredient. Its ingredients are commonly taken for weight loss, athletic performance and energy, digestive upset.Based on those ingredients, 957 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Bitter Orange peel extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Bitter Orange by Pure Herbs

Ask about any prescription or over-the-counter medication and we check it for interactions with Bitter Orange by Pure Herbs — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Bitter Orange by Pure Herbs

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 16, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: Bitter Orange peel extract. The extract delivers compounds — mainly synephrine, octopamine, and tyramine — that act as stimulants, affecting your heart rate and blood pressure.

There are no other inactive ingredients listed.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Bitter Orange's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: sinus and respiratory support.
  • We looked for evidence on: Allergic rhinitis (hay fever), Rhinosinusitis, sinusitis, nasal congestion, airway inflammation.
  • The closest evidence on file: Bitter Orange is rated "Insufficient Reliable Evidence To Rate" for Allergic rhinitis (hay fever) (Natural Medicines).
  • Also on file: Bitter Orange is rated "Insufficient Reliable Evidence To Rate" for Rhinosinusitis.

The evidence isn't established in our data for any of the uses linked to bitter orange. The facts we hold show insufficient reliable evidence to rate it for hay fever, hair loss, sexual dysfunction, pre-procedure anxiety, or athletic performance.

If you're considering it for one of these purposes, talk with your doctor or pharmacist about whether the evidence supports it and whether it's right for you.

The evidence, ingredient by ingredient Bitter Orange

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Bitter orange taken by mouth in medicinal amounts may be unsafe. The most common side effects are high blood pressure and a fast heartbeat, especially if you combine it with caffeine or other stimulants.

Rare but serious effects reported in case studies include heart attack, changes in heart rhythm, seizures, stroke, and fainting. When applied to skin or inhaled as aromatherapy, it's generally well tolerated, though skin irritation can occur topically.

The safety data advises against using this supplement during pregnancy because of its stimulant effects and lack of safety information. There also isn't enough safety data to use it while breastfeeding — talk with your doctor or pharmacist about whether it's right for you in either situation.

Side effects, ingredient by ingredient Bitter Orange

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Bitter Orange.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: diabetes medications; heart-rhythm medications.
  • For scale: 958 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Stop and check with your doctor or pharmacist before taking this if you're on MAOIs (older antidepressants), midazolam or other sedatives, drugs that affect heart rhythm, diabetes medications, stimulant drugs, cough suppressants like dextromethorphan, or if you use caffeine regularly. The interaction list is extensive — use the medication checker on this page to look up your exact drugs.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Major medication interactions have been identified, and safety information is well characterized.

Bitter Orange is a potent stimulant extract that carries serious interaction risks with many common medications, especially older antidepressants, sedatives, heart drugs, and stimulants. If you take any prescription or over-the-counter medication — or use caffeine regularly — you need to check your exact drugs with the tool on this page before starting it.

Talk it over with your own doctor or pharmacist to see if it's safe for your situation.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Dec 13, 2022.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Bitter Orange, straight from the product label.

Brand Pure Herbs
Net contents 4 Fluid Ounce(s); 120 mL
Market status On market
Date entered into DSLD Dec 13, 2022
DSLD ID 279738
Product type Botanical
Supplement form Liquid
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Women (not pregnant or lactating)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Bitter Orange by Pure Herbs, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
2 mL
Maximum serving Sizes:
2 mL
Servings per container
60
IngredientAmount% DV
Bitter Orange peel extract2049 mg--

Other ingredients: None

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Directions: For adults, mix 2 mL (abt. 1/2 tsp) of extract in 2 fl. oz (60 mL) water one time daily preferably with a meal.

Shake well before use

Formulation

Beneficial for sinus and respiratory support.

FDA Disclaimer Statement

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Precautions

Warning: Not intended for use by pregnant or nursing women. If you have a medical condition or are taking medication, consult your doctor prior to use.

Discontinue use and consult with your doctor if any adverse reactions occur.

Keep out of reach of children

Brand IP Statement(s)

Pure Herbs, Ltd. Natural Herbal Extracts

FDA Statement of Identity

Dietary Supplement

General Statements

"No expense has been spared to provide the finest nature has to offer."

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Bitter Orange by Pure Herbs label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Bitter Orange label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Bitter Orange by Pure Herbs

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size2 mL Dosage formLiquid Servings per container60 Amounts shown are per serving.

Bitter Orange peel extract

Interacts with
957 drugs
2049 mg per serving

Bitter orange is a citrus fruit whose extracts contain synephrine, a mild stimulant often added to weight-loss and energy supplements. Evidence that i...

Bitter Orange peel extract monograph & interactions

Other (inactive) ingredients: None. These complete the product’s ingredient list but are not active constituents.

Interaction report

Bitter Orange by Pure Herbs Drug Interactions

Want to check YOUR meds against Bitter Orange?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
957Drugs
10 Major 876 Moderate 71 Minor

Ingredients driving the most interactions

Bitter Orange peel extract 957

Individual Drug Interactions

The ingredients in Bitter Orange interact with 957 drugs. Click any drug to see the details.

1 of the 1 ingredient in Bitter Orange interact with drugs. Each result below shows which ingredient is responsible. Bitter Orange peel extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Bitter Orange with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Bitter Orange peel extract13 drug types · 957 drugs

Midazolam (Versed)

Bitter orange might increase blood levels of midazolam.
One small clinical study shows that bitter orange juice can increase midazolam levels, likely through inhibition of cytochrome P450 3A4 (CYP3A4). Theoretically, bitter orange might increase the risk of midazolam-related adverse effects.

Likelihood Probable Evidence B
Monoamine Oxidase Inhibitors (Maois)

Theoretically, taking MAOIs with synephrine-containing bitter orange preparations might increase the hypertensive effects of synephrine, potentially leading to hypertensive crisis.
Bitter orange contains tyramine, octopamine, and synephrine, which are MAO substrates.

Likelihood Probable Evidence D
Antidiabetes Drugs

Theoretically, bitter orange might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Some clinical research shows that drinking a tea containing bitter orange and Indian snakeroot reduces fasting and postprandial glucose levels in patients with type 2 diabetes who are using antidiabetes drugs. However, it is unclear if these effects are due to bitter orange, Indian snakeroot, or the combination. An animal study also shows that p-synephrine in combination with gliclazide , a sulfonylurea, causes an additional 20% to 44% decrease in glucose levels when compared with gliclazide alone.

Likelihood Possible Evidence B
Caffeine

Bitter orange might increase blood pressure and heart rate when taken with caffeine.
Small clinical studies show that taking bitter orange in combination with caffeine can increase blood pressure and heart rate in otherwise healthy normotensive adults. Theoretically, this might increase the risk of serious cardiovascular adverse effects.

Likelihood Possible Evidence B
Colchicine

Bitter orange might affect colchicine levels.
Colchicine is a substrate of P-glycoprotein and cytochrome P450 3A4 (CYP3A4). Bitter orange has been reported to inhibit CYP3A4 and increase levels of CYP3A4 substrates. However, one small clinical study in healthy adults shows that drinking bitter orange juice 240 mL twice daily for 4 days and taking a single dose of colchicine 0.6 mg on the 4th day decreases colchicine peak serum levels by 24%, time to peak serum level by 1 hour, and overall exposure to colchicine by 20%. The clinical significance of this finding is unclear.

Likelihood Possible Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

Bitter orange might increase levels of drugs metabolized by CYP3A4.
Small clinical studies suggest that single or multiple doses of freshly squeezed bitter orange juice 200-240 mL can inhibit CYP3A4 metabolism of drugs, causing increased drug levels and potentially increasing the risk of adverse effects. However, the extent of the effect of bitter orange on CYP3A4-mediated drug interactions is unknown. Some evidence suggests that bitter orange selectively inhibits intestinal CYP3A4, but not hepatic CYP3A4. Its effect on P-glycoprotein, which strongly overlaps with CYP3A4 interactions, is unclear. One small clinical study shows that drinking 8 ounces of freshly squeezed bitter orange juice has no effect on cyclosporine, which seems to be more dependent on hepatic CYP3A4 and P-glycoprotein than intestinal CYP3A4.

Likelihood Possible Evidence B
Dextromethorphan (Robitussin Dm, Others)

Bitter orange might increase blood levels of dextromethorphan.
One small clinical study shows that bitter orange juice increases dextromethorphan levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition. Theoretically, bitter orange might increase the risk for dextromethorphan-related adverse effects.

Likelihood Possible Evidence B
Felodipine (Plendil)

Bitter orange might increase blood levels of felodipine.
One small clinical study shows that bitter orange juice increases felodipine levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition. Theoretically, bitter orange might increase the risk for felodipine-related adverse effects.

Likelihood Probable Evidence B
Indinavir (Crixivan)

Bitter orange might increase blood levels of indinavir.
One small clinical study shows that bitter orange juice slightly increases indinavir levels, but this effect is likely to be clinically insignificant. Bitter orange selectively inhibits intestinal cytochrome P450 3A4 (CYP3A4); however, the metabolism of indinavir seems to be more dependent on hepatic CYP3A4. The effect of bitter orange on other protease inhibitors has not been studied.

Likelihood Possible Evidence B
Qt Interval-Prolonging Drugs

Theoretically, bitter orange might have an additive effect when combined with drugs that prolong the QT interval, potentially increasing the risk of ventricular arrhythmias.
One case report suggests that taking bitter orange in combination with other stimulants such as caffeine might prolong the QT interval in some patients.

Likelihood Possible Evidence D
Sildenafil (Viagra)

Bitter orange juice might increase blood levels of sildenafil.
A small clinical study in healthy adult males shows that drinking freshly squeezed bitter orange juice 250 mL daily for 3 days and taking a single dose of sildenafil 50 mg on the 3rd day increases the peak plasma concentration of sildenafil by 18% and the overall exposure to sildenafil by 44%. Theoretically, this may be due to inhibition of cytochrome P450 3A4 by bitter orange.

Likelihood Probable Evidence B
Stimulant Drugs

Theoretically, bitter orange might increase the risk of hypertension and adverse cardiovascular effects when taken with stimulant drugs.
Bitter orange appears to have stimulant effects.

Likelihood Possible Evidence B
Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, bitter orange might increase levels of drug metabolized by CYP2D6.
In vitro research shows that octopamine, a constituent of bitter orange, weakly inhibits CYP2D6 enzymes. This effect has not been reported in humans.

Likelihood Possible Evidence D
Bitter Orange peel extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Bitter Orange, from the product label.

Pure Herbs

See all Pure Herbs products
Name
Pure Herbs, Ltd.
City
Sterling Heights
State
MI
Phone Number
(800) 860-4372
Web Address
www.pureherbs.com
Pharmacist Counseling Corner

Bitter Orange by Pure Herbs: Common Questions

Does Bitter Orange by Pure Herbs interact with any medications?
Yes. Based on its ingredients, Bitter Orange has a known interaction with 957 medications, including 10 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Bitter Orange contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take Bitter Orange with caffeine?
No — combining bitter orange with caffeine can significantly raise your blood pressure and heart rate. Small studies show this combination increases both systolic and diastolic blood pressure, which raises the risk of serious heart problems. Avoid pairing them.
What are the most common side effects of Bitter Orange taken by mouth?
High blood pressure and a fast heartbeat are the most common effects, especially if you're also taking stimulants or caffeine. Rare but serious effects include heart attack, stroke, seizures, and fainting. Talk with your pharmacist about what to watch for.
Can I use Bitter Orange while pregnant or breastfeeding?
The safety data advises against it during pregnancy because of the stimulant effects and lack of safety information. There also isn't enough data to know if it's safe while breastfeeding. Talk with your doctor or pharmacist for personalized advice.
Does Bitter Orange actually work for any health conditions?
According to the evidence we hold, there isn't enough reliable data to rate it for hay fever, hair loss, sexual dysfunction, pre-procedure anxiety, or athletic performance. Ask your doctor if there's evidence for the specific use you're considering.
How does Bitter Orange affect medications broken down by the liver?
Bitter Orange can inhibit an important liver enzyme called CYP3A4, which breaks down many common drugs. When you take bitter orange with these medications, their blood levels can rise, raising the risk of side effects. This affects a very large group of medications — check your exact drugs on this page.
Is Bitter Orange safe if applied to skin or inhaled?
When applied to skin or inhaled as aromatherapy, bitter orange is generally well tolerated. Skin irritation and headache have been reported in some cases, but serious effects are not typical with these forms.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Bitter Orange label
Go deeper

The Full Monographs Behind Bitter Orange’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Bitter Orange

Interacts with 957 drugs

Bitter orange is a citrus fruit whose extracts contain synephrine, a mild stimulant often added to weight-loss and energy supplements. Evidence that it works for weight loss or performance i...

Read the full Bitter Orange monograph →
Sources

Sources & How We Checked

Bitter Orange's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 47 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Bitter Orange 47 references
  1. Penzak SR, Jann MW, Cold JA, et al. Seville (sour) orange juice: synephrine content and cardiovascular effects in normotensive adults. J Clin Pharmacol 2001;41:1059-63. PubMed
  2. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
  3. Calapai G, Firenzuoli F, Saitta A, et al. Antiobesity and cardiovascular toxic effects of Citrus aurantium extracts in the rat: A preliminary report. Fitoterapia 1999;70:586-92. DOI
  4. Keogh AM, Baron DW. Sympathomimetic abuse and coronary artery spasm. Br Med J 1985;291:940.
  5. Malhotra S, Bailey DG, Paine MF, Watkins PB. Seville orange juice-felodipine interaction: comparison with dilute grapefruit juice and involvement of furocoumarins. Clin Pharmacol Ther 2001;69:14-23. PubMed
  6. Pellati F, Benvenuti S, Melegari M, Firenzuoli F. Determination of adrenergic agonists from extracts and herbal products of Citrus aurantium L. var. amara by LC. J Pharm Biomed Anal 2002;29:1113-9. . PubMed
  7. Colker CM, Kalman DS, Torina GC, et al. Effects of Citrus aurantium extract, caffeine, and St. John's wort on body fat loss, lipid levels, and mood states in overweight healthy adults. Curr Ther Res 1999;60:145-153. DOI
  8. Penzak SR, Acosta EP, Turner M, et al. Effect of Seville orange juice and grapefruit juice on indinavir pharmacokinetics. J Clin Pharmacol 2002;42:1165-70. PubMed
  9. Edwards DJ, Fitzsimmons ME, Schuetz EG, et al. 6',7'-Dihydroxybergamottin in grapefruit juice and Seville orange juice: effects on cyclosporine disposition, enterocyte CYP3A4, and P-glycoprotein. Clin Pharmacol Ther 1999;65:237-44. PubMed
  10. Di Marco MP, Edwards DJ, Wainer IW, Ducharme MP. The effect of grapefruit juice and seville orange juice on the pharmacokinetics of dextromethorphan: the role of gut CYP3A and P-glycoprotein. Life Sci 2002;71:1149-60. PubMed
  11. Visentin V, Morin N, Fontana E, et al. Dual action of octopamine on glucose transport into adipocytes: inhibition via beta3-adrenoceptor activation and stimulation via oxidation by amine oxidases. J Pharmacol Exp Ther 2001;299:96-104.
  12. Nykamp DL, Fackih MN, Compton AL. Possible association of acute lateral-wall myocardial infarction and bitter orange supplement. Ann Pharmacother 2004;38:812-6. PubMed
  13. Fugh-Berman A, Myers A. Citrus aurantium, an ingredient of dietary supplements marketed for weight loss: Current status of clinical and basic Research. Exp Biol Med 2004;229:698-704.
  14. Suzuki O, Matsumoto T, Oya M, Katsumata Y. Oxidation of synephrine by type A and type B monoamine oxidase. Experientia 1979;35:1283-4. PubMed
  15. Nasir JM, Durning SJ, Ferguson M, et al. Exercise-induced syncope associated with QT prolongation and ephedra-free Xenadrine. Mayo Clin Proc 2004;79:1059-62.. PubMed
  16. Firenzuoli F, Gori L, Galapai C. Adverse reaction to an adrenergic herbal extract (Citrus aurantium). Phytomedicine 2005;12:247-8. PubMed
  17. Bouchard NC, Howland MA, Greller HA, et al. Ischemic stroke associated with use of an ephedra-free dietary supplement containing synephrine. Mayo Clin Proc 2005;80:541-5. PubMed
  18. Haller CA, Benowitz NL, Jacob P 3rd. Hemodynamic effects of ephedra-free weight-loss supplements in humans. Am J Med 2005;118:998-1003.. PubMed
  19. Bui LT, Nguyen DT, Ambrose PJ. Blood pressure and heart rate effects following a single dose of bitter orange. Ann Pharmacother 2006;40:53-7. PubMed
  20. Min B, Cios D, Kluger J, White CM. Absence of QTc-interval-prolonging or hemodynamic effects of a single dose of bitter-orange extract in healthy subjects. Pharmacotherapy 2005;25:1719-24. PubMed
  21. Gange CA, Madias C, Felix-Getzik EM, et al. Variant angina associated with bitter orange in a dietary supplement. Mayo Clin Proc 2006;81:545-8. PubMed
  22. Jordan S, Murty M, Pilon K. Products containing bitter orange or synephrine: suspected cardiovascular adverse reactions. Canadian Adverse Reaction Newsletter 2004;14:3-4.
  23. Burke J, Seda G, Allen D, Knee TS. A case of severe exercise-induced rhabdomyolysis associated with a weight loss dietary supplement. Mil Med 2007;172:656-8. PubMed
  24. Gray, S. and Woolf, A. D. Citrus aurantium used for weight loss by an adolescent with anorexia nervosa. J Adolesc.Health 2005;37(5):414-415. PubMed
  25. Haller, C. A., Duan, M., Jacob, P., III, and Benowitz, N. Human pharmacology of a performance-enhancing dietary supplement under resting and exercise conditions. Br J Clin Pharmacol 2008;65(6):833-840. PubMed
  26. Thomas, J. E., Munir, J. A., McIntyre, P. Z., and Ferguson, M. A. STEMI in a 24-year-old man after use of a synephrine-containing dietary supplement: a case report and review of the literature. Tex.Heart Inst.J 2009;36(6):586-590.
  27. Campbell-Tofte, J. I., Molgaard, P., Josefsen, K., Abdallah, Z., Hansen, S. H., Cornett, C., Mu, H., Richter, E. A., Petersen, H. W., Norregaard, J. C., and Winther, K. Randomized and double-blinded pilot clinical study of the safety and anti-diabetic ef
  28. Seifert, J. G., Nelson, A., Devonish, J., Burke, E. R., and Stohs, S. J. Effect of acute administration of an herbal preparation on blood pressure and heart rate in humans. Int J Med Sci 2011;8(3):192-197. PubMed
  29. Stohs, S. J., Preuss, H. G., Keith, S. C., Keith, P. L., Miller, H., and Kaats, G. R. Effects of p-synephrine alone and in combination with selected bioflavonoids on resting metabolism, blood pressure, heart rate and self-reported mood changes. Int J Med
  30. Wason, S., DiGiacinto, J. L., and Davis, M. W. Effects of grapefruit and Seville orange juices on the pharmacokinetic properties of colchicine in healthy subjects. Clin Ther 2012;34(10):2161-2173. PubMed
  31. Kaats, G. R., Miller, H., Preuss, H. G., and Stohs, S. J. A 60day double-blind, placebo-controlled safety study involving Citrus aurantium (bitter orange) extract. Food Chem Toxicol. 2013;55:358-362.
  32. Calapai, G., Firenzuoli, F., Saitta, A., Squadrito, F. R., Arlotta, M., Costantino, G., and Inferrera, G. Antiobesity and cardiovascular toxic effects of Citrus aurantium extracts in the rat: a preliminary report. Fitoterapia 12-1-1999;70(6):586-592. DOI
  33. Colker, C., Kalman, D., and Torina, G. Effects of Citrus aurantium extract, caffeine, and St. John's Wort on body fat loss, lipid levels, and mood states in overweight healthy adults. Curr Ther Res 1999;60:145-153. DOI
  34. Shara M, Stohs SJ. Safety evaluation of Bitter orange extract (p-synephrine) in healthy volunteers. J.Amer.Coll.Nutr. 2011;30:358.
  35. Lynch B. Review of the safety of p-synephrine and caffeine. Intertek-Cantox Report, 2013;1-20.
  36. Smith TB, Staub BA, Natarajan GM, et al. Acute myocardial infarction associated with dietary supplements containing 1,3-dimethylamylamine and Citrus aurantium. Tex Heart Inst J 2014;41(1):70-2. PubMed
  37. Shara M, Stohs SJ, Mukattash TL. Cardiovascular safety of oral p-synephrine (bitter orange) in healthy subjects: a randomized placebo-controlled cross-over clinical trial. Phytother Res. 2016;30(5):842-7.
  38. Liu Y, Santillo MF. Cytochrome P450 2D6 and 3A4 enzyme inhibition by amine stimulants in dietary supplements. Drug Test Anal. 2016;8(3-4):307-10. PubMed
  39. Abdelkawy KS, Donia AM, Turner RB, Elbarbry F. Effects of Lemon and Seville Orange Juices on the Pharmacokinetic Properties of Sildenafil in Healthy Subjects. Drugs R D. 2016 Sep;16(3):271-278. PubMed
  40. Gutiérrez-Hellín J, Salinero JJ, Abían-Vicen J, Areces F, Lara B, Gallo C, et al. Acute consumption of p-synephrine does not enhance performance in sprint athletes.J. Appl Physiol Nutr Metab. 2016;41(1):63-9. doi: 10.1139/apnm-2015-0299.
  41. Jung YP, Earnest CP, Koozehchian M, et al. Effects of ingesting a pre-workout dietary supplement with and without synephrine for 8 weeks on training adaptations in resistance-trained males. J Int Soc Sports Nutr. 2017;3;14:1. doi: 10.1186/s12970-016-0158- PubMed
  42. Jung YP, Earnest CP, Koozehchian M, et al. Effects of acute ingestion of a pre-workout dietary supplement with and without synephrine on resting energy expenditure, cognitive function and exercise performance. J Int Soc Sports Nutr. 2017;14:3. doi: 10.118
  43. Vatsavai LK, Kilari EK. Interaction of p-synephrine on the pharmacodynamic and pharmacokinetics of gliclazide in animal models. J Ayurveda Integr Med 2017; S0975-9476(16)30487-9. doi: 10.1016/j.jaim.2017.04.010.
  44. Ratamess NA, Bush JA, Stohs SJ, et al. Acute cardiovascular effects of bitter orange extract (p-synephrine) consumed alone and in combination with caffeine in human subjects: A placebo-controlled, double-blind study. Phytother Res. 2018;32(1):94-102.
  45. Gutiérrez-Hellín J, Ruiz-Moreno C, Del Coso J. Acute p-synephrine ingestion increases whole-body fat oxidation during 1-h of cycling at Fatmax. Eur J Nutr. 2019 Nov 5. PubMed
  46. Karimzadeh Z, Azizzadeh Forouzi M, Tajadini H, Ahmadinejad M, Roy C, Dehghan M. Effects of lavender and Citrus aurantium on pain of conscious intensive care unit patients: a parallel randomized placebo-controlled trial. J Integr Med 2021:S2095-4964(21)000 PubMed
  47. Koncz D, Tóth B, Bahar MA, Roza O, Csupor D. The Safety and Efficacy of Citrus aurantium (Bitter Orange) Extracts and p-Synephrine: A Systematic Review and Meta-Analysis. Nutrients 2022;14(19):4019. PubMed

See these in context on the Bitter Orange monograph →

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DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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