Tiesjema B, Jeurissen SMF, de Wit L, Mol H, Fragki S, Razenberg L
RIVM Report 2017-0069
Synephrine is a substance that occurs naturally in citrus fruits, particularly in bitter orange (Citrus aurantium). It is added to food supplements for weight loss or to improve sports performance. The use of synephrine has increased since ephedrine, a related substance, was prohibited. Ephedrine is prohibited because it may have adverse effects on health.
At present, there is no legislation in the Netherlands which limits the amount of synephrine in food supplements. A maximum permitted amount may be desirable, however, because adverse effects cannot be excluded. This has been demonstrated by a risk assessment conducted by RIVM. Due to insufficient data on the safety of synephrine, no safe dose can currently be derived. In particular, data on the effects of chronic exposure are lacking. It may be possible that an (indicative) maximum safe amount of synephrine in food supplements could be determined based on the intake from a normal diet.
It is known that synephrine can increase blood pressure. In addition, other adverse effects are reported on the cardiovascular system by people who have used preparations containing synephrine. This aspect is particularly relevant because people who are overweight, the target group for weight loss products, are particularly at risk from cardiovascular diseases. Synephrine may also interact with various other drugs, affecting their efficacy. In addition, the effects of synephrine can be magnified when combined with caffeine and/or physical activity.