The FDA is said to have of late instituted a crack down on weight loss supplements as a result of severe uncomfortable side effects and even death linked to some dietary supplements such as ephedra. The ban on ephedra products resulted to the development of so-called ephedra free weight loss supplements, these too are said to yield their particular fair share of problems and they too could possibly be meant to exactly the same fate as ephedra.

These ephedra free supplements are said to cause a boost in heartbeat and a some other unwanted side effects on healthy folks reported by a health expert who participated in the research.

The examination done with the University of California at Berkeley was the first one to research the health effects of reformulated weight loss supplements. On the list of things tested for included hypertension and heartbeat rate of volunteers who were given reformulated weight loss supplements made out of extracts of bitter orange.

Ever since the ban slapped on ephedra by FDA, an increasing number of weight loss product manufactures have converted to extracts of bitter orange. The USB study involved 20 healthy volunteers, who received sole doses of a weight loss supplement or a placebo.

The diet supplements tried in the research were Xenadrine EFX and Advantra Z, each of which contains bitter orange extracts. The applied drug was shown to effect a boost in heart pulse rate as high as 16 beats in one minute. The Thermogenic Xenadrine EFX in particular was shown to rev up heart rate by 13 per cent, something that makes it almost identical in performance to ephedra.

Bitter orange extracts have synephrine, a component specific to over 90% of citrus fruits but found in increased concentrations in fruits such as Sour orange, Zhi shi and bitter orange and that is generally used as a relief medication in the management of respiratory tract congestion and high blood pressure. Xenadrine EFX is known for a stimulant in the ingredient, usually caffeine. The quantity of caffeine is Xenadrine is thought to be roughly the same as 3 coffee cups. This is the element the cause the surge in blood pressure and people using this product are informed against over dosage.