Bitter orange

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    Sara Gardy, Sarah Schriewer

    Fact-checked

    by:

    Marina Shkayeva, Gregory Lopez
    Last Updated: September 4, 2025

    A molecule that is similar to ephedrine in mechanism, but less potent. Commonly referred to as "bitter orange", synephrine appears to be a less potent fat-burner relative to ephedrine. It may exert some minor health effects on digestion and circulation.

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    Overview

    Dosage information

    A recommended dosage is 10-20mg, taken thrice a day.

    Acute dosages of 50mg are also frequently used, although not thrice a day.

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    Examine Database: Bitter orange

    Research FeedRead all studies

    Frequently asked questions

    Update History

    Examine Database References

    1. Appetite - Stohs SJ, Preuss HG, Keith SC, Keith PL, Miller H, Kaats GREffects of p-synephrine alone and in combination with selected bioflavonoids on resting metabolism, blood pressure, heart rate and self-reported mood changesInt J Med Sci.(2011 Apr 28)
    2. Blood Pressure - Penzak SR, Jann MW, Cold JA, Hon YY, Desai HD, Gurley BJSeville (sour) orange juice: synephrine content and cardiovascular effects in normotensive adults.J Clin Pharmacol.(2001-Oct)
    3. Blood Pressure - Shara M, Stohs SJ, Smadi MMSafety evaluation of p-synephrine following 15 days of oral administration to healthy subjects: A clinical study.Phytother Res.(2018-Jan)
    4. Blood Pressure - Bui LT, Nguyen DT, Ambrose PJBlood pressure and heart rate effects following a single dose of bitter orangeAnn Pharmacother.(2006 Jan)
    5. Blood Pressure - Min B, Cios D, Kluger J, White CMAbsence of QTc-interval-prolonging or hemodynamic effects of a single dose of bitter-orange extract in healthy subjectsPharmacotherapy.(2005 Dec)
    6. Blood Pressure - Ratamess NA, Bush JA, Stohs SJ, Ellis NL, Vought IT, O'Grady EA, Kuper JD, Hasan SB, Kang J, Faigenbaum ADAcute 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-Jan)
    7. Blood Pressure - Shara M, Stohs SJ, Mukattash TLCardiovascular Safety of Oral p-Synephrine (Bitter Orange) in Healthy Subjects: A Randomized Placebo-Controlled Cross-over Clinical Trial.Phytother Res.(2016-May)
    8. Blood Pressure - Koncz D, Tóth B, Bahar MA, Roza O, Csupor DThe Safety and Efficacy of (Bitter Orange) Extracts and -Synephrine: A Systematic Review and Meta-Analysis.Nutrients.(2022-Sep-28)
    9. Blood Pressure - Kaats GR, Miller H, Preuss HG, Stohs SJA 60day double-blind, placebo-controlled safety study involving Citrus aurantium (bitter orange) extract.Food Chem Toxicol.(2013-May)
    10. Hematocrit - Bush JA, Ratamess NA, Stohs SJ, Ellis NL, Vought IT, O'Grady EA, Kuper JD, Kang J, Faigenbaum ADAcute hematological and mood perception effects of bitter orange extract (p-synephrine) consumed alone and in combination with caffeine: A placebo-controlled, double-blind study.Phytother Res.(2018-Aug)
    11. Weight - Greenway F, de Jonge-Levitan L, Martin C, Roberts A, Grundy I, Parker CDietary herbal supplements with phenylephrine for weight loss.J Med Food.(2006)
    12. Carbohydrate Oxidation - Gutiérrez-Hellín J, Del Coso JEffects of p-Synephrine and Caffeine Ingestion on Substrate Oxidation during Exercise.Med Sci Sports Exerc.(2018-Sep)
    13. Carbohydrate Oxidation - Gutiérrez-Hellín J, Ruiz-Moreno C, Del Coso JAcute p-synephrine ingestion increases whole-body fat oxidation during 1-h of cycling at Fatmax.Eur J Nutr.(2020-Oct)
    14. Carbohydrate Oxidation - Gutiérrez-Hellín J, Del Coso JAcute p-synephrine ingestion increases fat oxidation rate during exerciseBr J Clin Pharmacol.(2016 Aug)
    15. Carbohydrate Oxidation - Gutiérrez-Hellín J, Aguilar-Navarro M, Ruiz-Moreno C, Muñoz A, Amaro-Gahete FJ, Posada-Ayala M, López-Samanes Á, Del Coso J, Varillas-Delgado DEffect of -Synephrine on Fat Oxidation Rate during Exercise of Increasing Intensity in Healthy Active Women.Nutrients.(2022-Oct-17)
    16. Carbohydrate Oxidation - Gutiérrez-Hellín J, Del Coso J, Aguilar-Navarro M, Varillas-Delgado D, Ruiz-Moreno C, López-Samanés Á, Amaro-Gahete FJ, Muñoz ADoes the Time of Day Play a Role in the Acute Effect of -Synephrine on Fat Oxidation Rate during Exercise in Women? A Randomized, Crossover and Double-Blind Study.Nutrients.(2022-Nov-26)
    17. Sprint Performance Metrics - Gutiérrez-Hellín J, Salinero JJ, Abían-Vicen J, Areces F, Lara B, Gallo C, Puente C, Del Coso JAcute consumption of p-synephrine does not enhance performance in sprint athletes.Appl Physiol Nutr Metab.(2016-Jan)
    18. Blood Pressure - Benjamim CJR, Júnior FWS, Porto AA, Rocha ÉMB, Santana MD, Garner DM, Valenti VE, Bueno Júnior CRBitter Orange Intake Before Submaximal Aerobic Exercise Is Safe for Cardiovascular and Autonomic Systems in Healthy Males: A Randomized Trial.Front Nutr.(2022)
    19. Carbohydrate Oxidation - Ratamess NA, Bush JA, Kang J, Kraemer WJ, Stohs SJ, Nocera VG, Leise MD, Diamond KB, Campbell SC, Miller HB, Faigenbaum ADThe Effects of Supplementation with p-Synephrine Alone and in Combination with Caffeine on Metabolic, Lipolytic, and Cardiovascular Responses during Resistance Exercise.J Am Coll Nutr.(2016)