Many supplements come and go, while few stand the tests of time; this is typically due to a lack of evidence either in the research labs or anecdotally with the athletes themselves, however, it can also be due to safety concerns.
Ephedrine is just one example of a product that was here for several years and was an effective fat loss supplement; however, it was recently banned due to a number of safety concerns. Now individuals and companies are in search of an effective replacement for ephedrine and synephrine has recently "stepped up" as the next in line for a sound replacement. The question now, is does this product truly work?
While the inclusion of synephrine (Citrus aurantium) in "ephedrine free" products is common, there is surprisingly little research to support or refute its function. A recent review was published discussing the use and safety of synephrine. Let's start with a brief overview.
Citrus aurantium (also called Seville orange or sour orange) is a small citrus tree. Growing these in your back yard with the intention of gnawing on the fruit of the tree to lose weight isn't the best idea because few could handle its extremely sour taste. The peel of this fruit is commonly used in marmalades (obviously with loads of added sugar to make it palatable), certain beers, and some alcohols.
Contrary to the popularity of this supplement, there has only been one weight loss study to date published in a peer-reviewed journal regarding its efficacy. Moreover, this study didn't solely use synephrine, but rather a product that combined synephrine with several other ingredients.
This particular study used a product that contained 975 mg C. aurantium extract (6% synephrine compounds), 528 mg caffeine, and 900 mg St. John's wort (3% hypericum). The subjects in the study took the product for 6 weeks and the researchers measured fat loss, weight, metabolic rate, blood lipids, blood pressure, and mood.
The researchers reported a 1.4 kg weight loss in the supplement group versus a 0.9 kg loss in the placebo group. Although these results were statistically significant, they were not compared to each other, but rather the baseline value. Therefore, no conclusion can be drawn from their results. That is only about a 1 lb difference.
There was also a higher percentage of fat lost in the supplemented group versus the placebo; however, this too was compared to the baseline value (meaning the values for those in the supplement group were compared to the endpoints rather than comparing the groups against one another).
There was a significant increase in metabolic rate, which is not surprising considering there is the same amount of caffeine in this product as approximately 4 cups of coffee.
No significant changes were seen in any of the other outcome measures and no side effects were reported. In conclusion, the only published literature to date using C. aurantium demonstrated it is not superior to placebo.
One also must be careful because it has been shown that C. aurantium may affect certain medications. This is obviously a concern because drugs are prescribed with a known benefit or change; however, if taking a product simultaneously that interferes with the effectiveness of a pharmaceutical drug, you could run into some problems.
The other concern is that synephrine is on the FDA "watch list," meaning it too could follow in the footsteps of its chemical cousin, ephedra and soon be off the market. This may not be good for companies, as it may hurt profits; however, with only one study measuring the safety and efficacy of this product for fat loss in humans, there is a lot more that need to be done.
If researchers can begin to show that this product does in fact work and is safe, we're in luck. However, until then companies will either continue to look for other ingredients to stand alone or complement other "fat loss" ingredients. When it came to fat loss products, ephedrine was definitely king; let's see if synephrine is ready for the job.