The following is the first draft of an article I wrote on norephedrine. I never finsihed it because on MFW, where I primarily posted at the time, we were well aware of the fact that it was not thermogenic in humans, so I sort of thought it was a pointless article. I may have to finish it after all.
Anyway, the article does not have the references added in, so I suppose you could assume i am making it up -- even though I doubt even 1 out of 100 people actually check references
Norephedrine Revisited
The Hype
A couple years ago, we were informed of the latest breakthrough in fat loss – a substance that would make our beloved ephedrine obsolete. It was twice as thermogenic, a better appetite suppressant – and at the same time caused far less CNS stimulation (it is arguable whether that is good or bad, but it was certainly a good selling point for those paranoid about the dangers of ephedrine.)
The Controversy
Of course, it did not replace our beloved ephedrine. Why? Because it was not significantly thermogenic – at least not in humans. The studies that the creative geniuses behind this product cited were not on humans – they were on rats. (In fact, there are precious few studies on l-norephedrine in humans. There are numerous ones on dl-norephedrine – aka phenylpropanalamine (PPA) – aka Dexatrim – but we will get to that in a moment.)
Unfortunately, the andrenergic systems of rats and humans are quite different, thus substances acting upon them have markedly different effects – a very unfortunate occurrence if you are not a rat and wish to lose bodyfat – as it would have made this a magnificent product (not to mention the selective beta 3 agonist that sits in a pile of research papers in my office).
Strangely, its pushers have not backed off of their claim despite the clamors of those who say it is only thermogenic in rats. Let us settle this debate once and for all.
The Data
So, what does the research say on norephedrine’s effects in humans? As mentioned earlier, the vast majority of studies are on the racemic mixture. But, the “d” isomer has almost no activity, and the “l” isomer has twice the activity of the “dl” mixture, so we can conclude that it is the “l” isomer causing the effects when “dl” is employed. So, the remainder of the research cited will be on “dl” unless otherwise noted.
The first hint that this would not be a particularly thermogenic compound is that it is an alpha 1 agonist – not a beta agonist. In fact, it is also a partial alpha 2 agonist – and, as we know a2’s are anti-thermogenic in that they cause reuptake of norepinephrine – a powerful endogenous b2 agonist (and mediator of much of ephedrine’s thermogenic effects).
The second hint is that numerous studies have found that it did not increase REE (i.e. it is not causing excess energy to be given off as heat – i.e it is not thermogenic)
Partial Redemption??
So, is it a total fraud? Again, let us look to the research. One thing in its favor is that it is without question a powerful appetite suppressant. It is also true that it does not cause the increases in heart rate and b.p. associated with ephedrine (though the data on b.p. are mixed, even the studies finding increases did not find even borderline clinical hypertension). The ability to safely control diet is an obvious plus – particularly for the very obese who both eat way too much and are at a greater risk for the side effects of ephedrine than their lean counterparts.
It also might might not be without benefits on weight loss above and beyond its anorectic effects. A couple of studies (on humans) found that subjects on PPA lost more weight than controls despite equal food intake.
****Note -- I now know the mechanism behind this.****
The fact that norephedrine has generally been included with several other ingredient also proves to be a serendipitous plus – the two most popular products using norephedrine also contain yohimbine, which would negate its a2 agonism, as well as caffeine – and norephedrine elevates blood levels of caffeine, which would elevate norephedrine levels – which IS thermogenic.
So, as with basically all supplements, it was overhyped, but is actually a decent product.
ParDeus
Big Motherfucker bodybuilding magazine
Issue #3 now on-line.
http://www.avantlabs.com/issue3/big_mfr_issue_3.htm