Limited research did not find a benefit. An analysis of 3 small studies found that taking 10–54 mg of synephrine daily for 6–8 weeks had no significant effects on weight loss or fat mass.[1]
Limited research suggests that bitter orange supplements may increase fat oxidation during exercise and affect resting metabolic rate. One small study of 14 healthy adults found that taking a single dose of p-synephrine prior to one hour of cycling exercise, at a dosage of 3 mg of synephrine per kg of body weight (3 mg/kg), increased the amount of fat burned and decreased the amount of carbohydrates utilized, but did not affect total energy expenditure compared to placebo.[2]. Another small study found that 10 individuals given 50 mg of synephrine had a 65 kcal increase in their resting metabolic rate compared to placebo, but this result was not significant.[3]
References
- ^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)
- ^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)
- ^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)