[quote]big69penisman wrote:
Cy Willson wrote:
Actually, neither study was using men. Both were using 5 overweight women.
However, I have to argue that it’s not accurate to assume that research in women can’t be applied to men. I see people make that mistake quite often when looking at abstracts. Unless you’re talking about an effect that is directly and significantly dependent upon sex hormones, it’s not unreasonable to assume that on a qualitative level, something similar will happen in males. If one takes a look at available weight loss drugs, or really, the vast majority of drugs in general, they’ll see that they are not sex-dependent.
So, the study you found still has value.
As for the study evaluating a thermogenic response (the other was a continuation of the first study, this time evaluating the effect upon glucose induced thermogenesis), it’s not that it was actually demonstrated that the ephedrine became more effective in terms of reducing fat mass. This is not what they found.
Rather, they were measuring metabolic rate via oxygen consumption. They first administered ephedrine on a single day (prior to initiating the 12 week study) and measured oxygen consumption.
Each subject then began taking 20 mg, three times daily.
At weeks 4 and 12, they repeated the ephedrine load and again measured metabolic rate via oxygen consumption. They then compared oxygen consumption from their pre-trial measurement to weeks 4 and 12, and as one would expect, found a much larger increase. However, one major flaw is that the author never considers the half-life (never makes any mention about it) of ephedrine. Well, considering that one had just been taking 60 mg/day for 4 and 12 previous weeks, it should be a no brainer that one is going to have higher blood levels after an oral load of ephedrine than they would when they were administered ephedrine prior to the study beginning. In fact, if oxygen consumption truly were increasing with continual use, you’d expect to see an increase going from week 4 to week 12, yet there was no significant difference (week 12 had a decrease in fact, though not significant).
Actual measured fat loss did not persist at the same rate, nor increase in this study. As one would expect, it decreased over time.
In any event, the reason I asked to see such a study is simply because it’s as close to being dogmatic as possible in molecular/cell biology that chronic administration of a beta adrenergic agonist will produce down-regulation (not to be confused with desensitization which is much more acute) and hence a diminished biological response. In fact, that’s what is demonstrated over and over. Now, that of course doesn’t mean there aren’t other mechanisms through which an effect upon metabolism couldn’t be maintained, but to have such a powerful effect that one continues to reduce fat mass at a greater rate than when starting administration would be nothing short of amazing. This study simply did not demonstrate that.
big69penisman wrote:
Here’s the earlier study. This one was in overweight women where things are screwy, but the previous one was in healthy men which should mean something (this type of research is not my first hand thing, so I may be wrong).
Enhanced thermogenic responsiveness during chronic ephedrine treatment in man.
Astrup A, Lundsgaard C, Madsen J, Christensen NJ.
The thermogenic effect of a single oral dose of ephedrine (1 mg/kg body weight) was studied by indirect calorimetry in five women with 14% overweight before, during and 2 mo after 3 mo of chronic ephedrine treatment (20 mg, perorally, three times daily). Before treatment and 2 mo after its cessation a similar thermogenic response to ephedrine was observed. The total extra consumption of oxygen was 1.3 1 before and 1.2 1 after cessation of the chronic treatment. After 4 and 12 wk of treatment ephedrine elicited a more sustained response, the extra oxygen consumption in the 3 h following ephedrine intake being 7.0 and 6.9 1, respectively. The ratio of serum T3 to T4 increased significantly after 4 wk of treatment (15.6 +/- 1.3 vs 19.4 +/- 2.4; p less than 0.05), but decreased below the initial value after 12 wk treatment. The mean body weight was significantly reduced after 4 and 12 wk of treatment (2.5 and 5.5 kg, respectively). An improved capacity for beta-adrenergic induced thermogenesis may be useful in the treatment of obesity.
PMID: 4014068 [PubMed - indexed for MEDLINE]
Thanks for the reply. I mistyped that, meant females. The only other long study I found was this one that had a 50 week study. Didn’t show increased Thermogenesis, but it continued to work.
Safety and efficacy of long-term treatment with ephedrine, caffeine and an ephedrine/caffeine mixture.
Toubro S, Astrup AV, Breum L, Quaade F.
Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Fredriksberg, Copenhagen, Denmark.
In a randomized, placebo-controlled, double blind study, 180 obese patients were treated by diet (4.2 MJ/day) and either an ephedrine/caffeine combination (20mg/200mg), ephedrine (20mg), caffeine (200mg) or placebo 3 times a day for 24 weeks. 141 patients completed this part of the study. All medication was stopped between week 24-26 in order to catch any withdrawal symptoms. From week 26 to 50, 99 patients completed treatment with the ephedrine/caffeine compound in an open trial design, resulting in a statistically significant (p = 0.02) weight loss of 1.1kg. In another randomized, double-blind, placebo-controlled 8 week study on obese subjects we found the mentioned compound showed lean body mass conserving properties. We conclude that the ephedrine/caffeine combination is effective in improving and maintaining weight loss, further it has lean body mass saving properties. The side effects are minor and transient and no withdrawal symptoms have been found.
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No problem!
Well, let’s take a look at this. This was 24 weeks of administration (double-blinded) followed by a 2 week break and then another 24 weeks followed that, this time as an open trial (not blinded-subjects knew what they were taking).
So, just to be anal about it, it was 24 weeks followed by a 2 week break, then treatment continued in a different study design for 24 weeks. So, 48 weeks of treatment, split in half by a 2 week break. Again though, only half of that 48 was using the “gold standard” trial design…though a psychologist friend always makes me question how “golden” it truly is.
That aside, this doesn’t demonstrate an increase in effectiveness nor a maintenance of initial effectiveness.
I’m not arguing one iota that ephedrine and caffeine will become completely ineffective with continual use. Rather, I’m saying that it doesn’t become more effective with continual use nor will initial effectiveness be maintained. If one takes a look at the effects across time, they’ll see just that. Again, going back to what is considered an expected and documented response, beta adrenergic receptors will down-regulate in response to continued agonism, resulting in a diminished biological response.
