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# Weight loss supplement synephrine does not increase blood pressure
- URL: https://www.foodconsumer.org/weight_loss_synephrine_blood_pressure_0420140347/
- Published: 2014-04-20T16:46:00.000Z
- Updated: 2026-09-22T16:10:11.000Z
- Description: In a crossover trial of 10 healthy adults, the multi-ingredient supplement Xenadrine EFX raised systolic and diastolic blood pressure while Advantra Z, carrying eight times more synephrine, did not. The authors attribute the effect to caffeine and other stimulants.
- Author: Food Consumer
- Tags: Obesity, Avoiding Illness, #vivvo-import

Sunday April 20, 2014 (foodconsumer.org) -- A small trial of healthy individuals indicates that even high doses of weight loss dietary supplement synephrine itself do not induce high blood pressure. What induce high blood pressure may be caffeine and other stimulants that are used together with synephrine. 

Christine A. Haller from University of California in San Francisco, California and colleagues conducted the study to investigate the effects of ephedra-free weight loss supplements C. aurantium (Advantra Z) with synephrine and Xenadrine EFX with synephrine 

Synephrine or its source called or bitter orange (citrus aurantium) is now commonly used to replace ephedra as a weight loss supplement. However, some studies claim that synepherine can increase risk of high blood pressure or even cardiovascular events, side effects that are found associated with ephedra.

For the randomized, double-blind, placebo-controlled, three-arm crossover study, 10 healthy adult nonsmokers were randomly assigned single doses of C. aurantium (Advantra Z) with 46.9 mg synephrine, Xenadrine EFX, a multi-ingredient formula with 5.5 mg synephrine, and placebo.

Weight loss aid Xenadrine EFX but not Advantra Z increased systolic and diastolic blood pressure. Advantra Z increased heart rate compared with the baseline at six hours of taking the supplement by 11.4 beats per minute, compared with 16.7 beats per minutes with Xenadrine EFX.

The researchers concluded " Ephedra-free weight loss supplements have significant cardiovascular stimulant actions, similar to ephedra. These effects are not likely caused by C. aurantium alone, because an eightfold higher dose of synephrine (Advantra Z) had no effect on blood pressure, but may be attributable to caffeine and other stimulants in the multi-component formulation."

The study was published recently in the American Journal of Medicine. (David Liu)