Synephrine, also sold as the ingredient Advantra Z is found in the citrus aurantium fruit, or bitter orange. You will often see diet pills include any of these ingredients, but the goal of inclusion is for the synephrine.
One study found that a certain orange peel (Satsuma manderin orange) which contains synephrine was effective in the fat loss in rats when treated. That study concluded that “These results suggest that the segment wall, an edible fraction, from Satsuma mandarin orange might be useful as a functional food, especially as a fat-reducing material.” ((J Nutr Sci Vitaminol (Tokyo). 2008 Dec;53(6):547-51.)) This clinical study was done in 2007, pretty recent.
Unfortunately, there are a few other studies on the ingredient synephrine, but not much. What we’ve seen so far is supportive, leading us to believe that the claims that synephrine aids in weight loss through lypolysis are likely to be true.
A note should be said about the origins of synephrine. Some diet pill companies will include bitter orange or citrus aurantium which contains synephrine, but they cite it as though it’s almost pure synephrine. This is not true and should be monitored. Synephrine seems to be effective, and bitter orange or citrus aurantium are good sources of it, but just be mindful that if you’re getting, say, 100 mg of citrus aurantium, you are not getting a full 100 mg of synephrine. There, I think I’ve beat that point to death.
Synephrine is likely to be an effective weight loss ingredient in a weight loss pill. While synephrine is claimed not to have some of the same side effect as caffeine may have (such as the jitters), it is a stimulant so those who don’t fare well with stimulants should take note. While there is still research to be done to solidify these claims, we like what we see so far in the clinical studies that we’ve found. Thumbs up for synephrine.