Synephrine . . . A "New" Fat Burner

I've included a fair amount of information on ephedrine at this site, and it's been a frequent topic on my radio show. Why? Because so many products from stay awake pills to metabolism boosters and fat burners contain ephedrine as their primary ingredient. The word is slowly getting out that ephedrine is potentially dangerous, perhaps life-threatening. The supplement sellers are on track to make 1.2 Billion Dollars in ephedrine related sales this year (2002). You can understand why they don't want their goldmine to cave in.

Now, as people are scanning labels for ephedrine, ephedra, or Ma Huang, many "fat burners" are being sold as "ephedrine-free." They include as a key ingredient something called Synephrine. As with ephedrine, synephrine can be found under different herbal names including Advantra Z, Bitter Orange, Citrus aurantium, zhi shi, and shangzhou zhiqiao fructus Aurantii (say that ten times fast!).

People have asked me frequently about synephrine and repeatedly expressed that when they tried to find information on the web, all they found were thousands of advertisements for fat burners. What is this stuff?

Put your brain to work for a minute. Where have you heard or seen that word before? Synephrine. Can you think of it? OK, let me help. Envision the shelves in the Cold Relief section of your pharmacy. Think nasal spray. Aha! Neo-Synephrine. Is it any surprise we're finding something by the same name sold as an over the counter cold relief aid? It shouldn't be. After all, ephedrine is sold in pharmacies as Primatene Tablets. Despite their herbal sources, ephedrine and synephrine are over the counter drugs.

The newest "ephedrine-free" formulas use synephrine and in their marketing literature use the same promotional jargon as they do to sell ephedrine. They call it "thermogenic" and claim it burns fat. "Thermogenic" actually means "initiates heat" and since metabolism is directly correlated to the body's generation of heat, the thinking is, crank things up a degree or so and more calories are burned. Ephedrine, when combined with caffeine, does have thermogenic properties, but synephrine is not the same thing. Ephedrine is a beta adrenergic agonist. Synephrine is an alpha adrenergic agonist. Don't worry . . . in a moment I'll explain those terms. For now, all I want you to know is that their actions (ephedrine and synephrine) are different. You might feel warm after taking synephrine, but that warmth comes from a very different mechanism than ephedrine induced heat.

Neo-Synepherine is used to stop a "runny nose" because it has a vasoconstriction effect. Synephrine constricts the blood vessels. Contricted blood vessels equals restricted blood flow, and that's the complete opposite of what you want if you're looking to optimize fat burning, yet it may cause a sensation of heat.

If you were to look at the ingredient label of Neo-Synephrine, you wouldn't find "bitter orange" or even synephrine. What you would find is phenylephrine. Phenylephrine and synephrine are isomers (they are composed of the same molecular material in different configurations) thus it's probable many of their effects will be the same. Is there research on synephrine? Yup. I'll get more into that in a moment. Is there an abundance of research proving that synephrine administered to human beings acts as a fat burner? Absolutely not. Conversely, Neo-Synephrine has been on the market since 1940, so there's lots of real world trial. The side effects label of the nasal spray should provide some preliminary insight into the potential side effects of synephrine.

From the Label of Neo-Synephrine:

Do not use this product for more than 3 days and use only as directed. Frequent or prolonged use may cause nasal congestion to recur or worsen. If symptoms persist, consult a doctor. Side effects: General stimulation causing increased heart rate and blood pressure, insomnia, nervousness, anxiety, tremor, dry mouth, blurry vision, and headache. It may also cause an inability to urinate. Therefore, consult a physician if you have any history of cardiac disease, high blood pressure, anxiety, or urinary problems. Also, combining decongestants with other other-the-counter or prescribed medicines with similar side effects may lead to dangerous complications.

I haven't seen such warnings posted on synephrine products aimed at "fat burning." That should raise a red flag. Unfortunately, with supplements, it isn't until people suffer or die that the FDA begins to investigate the safety of a product.

Synephrine and phenylephrine are both categorized as alpha-adrenergic agonists. Uh-oh, there I go with those big words again. Don't worry. I promised an explanation and I've never let you down so far, have I? Allow me to clarify these terms.

The little signal receiving sites that regulate the actions of the central nervous system can be divided into two types, alpha adrenergic receptors and beta adrenergic receptors. An agonist is something that stimulates an action at the receptor site. Alpha receptors and beta receptors have different roles. The beta adrenergic receptors increase the force of contraction in the circulatory system and produce bronchodilation (the opening up of bronchial passages). Remember, ephedrine is a beta adrenergic agonist. The receptor that produces vasoconstriction is referred to as an alpha receptor. The two receptors are normally stimulated by the production of neurotransmitters and hormones such as adrenalin, norephinephrine, and dopamine. Specific drugs that interrupt nervous system activity have an affinity to act more at the beta sites, others at the alpha sites.

OK. Now that I've shared a bit of biochemistry, on to the research (this won't be anywhere near as complicated)! All of the ads claim there has been extensive research on synephrine. Has there? Yes, but again, most of it was not done on humans. Here's one research study that I've seen quoted in ads.

Park JH, Keeley LL. The effect of biogenic amines and their analogs on carbohydrate metabolism in the fat body of Blaberus discoidalis. Gen Comp Endocrinol 1998 Apr;110(1):88-95

Does this study prove that synephrine (a biogenic amine) will burn fat in your body? Only if you fall into the species categorized as Blaberus discoidalis. Allow me translate Blaberus discoidalis into its more recognizable term. Cockroach!

Here's another study that used "bitter orange" (an herb from which we get synephrine):

Mwaiko GL. Citrus peel oil extracts as mosquito larvae insecticides. East Afr Med J 1992 Apr;69(4):223-6

In this study, it was proven that syneprine kills mosquitos. Wow, that has a lot to do with fat burning in people, doesn't it? If someone told you to buy mosquito repellant and use it as a fat burner, wouldn't you think twice? My point is, when they say there is an abundance of research on synephrine, you have to question the specifics of the research conducted. Rabbits, rats, and roaches have all ingested synephrine in the pursuit of science . . . and if you choose to experiment on your own body . . . that's entirely up to you. If, however, the goal is to burn fat, my suggestion is to leave the synephrine on the shelves with ephedrine and develop a concern for supportive eating and exercising.

The ads openly claim that "synephrine is proven safe," but if we recognize that risk may be cumulative, how, in a short period of time, can anything be proven "safe?" The ads may point you to some studies that may or may not hint at synephrine safety, but they surely won't point you toward this study:

Diane L Nykamp, Majed N Fackih, and Anthony L Compton. Possible Association of Acute Lateral-Wall Myocardial Infarction and Bitter Orange Supplement. Ann. Pharmacother., May 2004; 38: 812 - 816

The abstract discusses an incident of a 55-year old woman who went to the hospital with dull aching pain in her shoulder was diagnosed with a lesion in the left main coronary artery. She had been taking a supplement containing 300 mg of bitter orange (citrus aurantium - synephrine) for the past year and had absolutely no prior history of any cardiac disturbance. She was diagnosed with acute lateral-wall Myocardial Infarction (heart attack) and was hospitalized for four days. After review, what was the conclusion of the study? The use of supplements containing citrus aurantium may present a risk for cardiovascular toxicity.

Is it possible synephrine can aid in fat release? Yes. Is it likely to be significant or in any way superior to eating right and exercising effectively? No. Some companies are "stacking" synephrine with caffeine and ephedrine to cover all bases. Perhaps, by using synephrine, a lower dosage of ephedrine can minimize the stimulant buzz. There is lots of room for continued experimentation. I just wouldn't encourage you to position yourself as a guinea pig. There just isn't any need.

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