The National Collegiate Athletic Association (NCAA) lists synephrine (bitter orange) as a banned stimulant. One small study found that taking 100 mg of synephrine slightly enhanced muscle endurance during resistance exercise compared to control.[1]
A longer-duration study found that 4 weeks of daily administration of a supplement containing 20 mg synephrine improved some areas of exercise performance, but after 8 weeks no clear differences compared to the supplement without synephrine were noted.[2]
References
- ^Ratamess NA, Bush JA, Kang J, Kraemer WJ, Stohs SJ, Nocera VG, Leise MD, Diamond KB, Faigenbaum ADThe effects of supplementation with P-Synephrine alone and in combination with caffeine on resistance exercise performance.J Int Soc Sports Nutr.(2015)
- ^Jung YP, Earnest CP, Koozehchian M, Cho M, Barringer N, Walker D, Rasmussen C, Greenwood M, Murano PS, Kreider RBEffects 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)