NEW Xenadrine RFA-1™ Review: Clinical Strength Weight Loss?

Xenadrine RFA-1, quite frankly, is one of the most recognizable fat burner brand names in history (only Muscle Tech's Hydroxycut supercedes it, in my opinion). It has taken several forms over the last several years—the original ephedra-based Xenadrine RFA-1, and later, the ephedra-free version.

In the past, this product wasn't immune from controversy. Cytodyne/Nutriquest were forced to pay close to a million dollars in customer redress for making false and unsubstantiated claims in regards to their claims for both Xenadrine RFA-1 and EFX. In the past, Nutraquest was forced to declare bankruptcy to avoid a growing number of ephedra-based lawsuits. And even the Federal Trade Commission went after the marketers of Xenadrine EFX.

Hardly inspiring stuff.

Nonetheless, I can say that these issues notwithstanding, the Cytodyne/Nutriquest fat burner products were actually pretty decent; the original ephedra-based Xenadrine RFA-1 was very popular, and most customers who wrote in to UltimateFatBurner.com loved the product.

So what's up with the new version?

Well for one, it's distributed by a company called Cytogenix Laboratories. I used several online "company research" resources, but drew a blank trying to determine who is behind this company, as it does not appear to be publicly traded.

In other words, I could not determine whether this company is a renamed version of Nutriquest / Cytodyne / Bioquest, or whether there really is a brand new group of people behind the product.

A little digging by our intrepid scientific and technical advisor Elissa revealed however, that the new owners of the Xenadrine brand is none other than Iovate, better known as Muscle Tech.

Small world, huh?

That said, let's have a look at the formulation. What's in the new "clinical strength" Xenadrine RFA-1 with the patented "triple action technology?"...

1) Vitamin blend: A series of B-vitamins, calcium, potassium, and chromium polynicotinate—an ingredient which may help with craving control and weight loss. B-vitamins are often included in popular fat burners because of their role in a properly functioning metabolism (specifically, the breakdown of various macronutrients). Unless you're deficient in them however, it's unlikely supplementation will yield in dramatic results of any sort. Standard stuff, really.

2) Lipo-Core™ complex: A 1,187 mg proprietary complex consisting of...

• Garcinia Cambogia or Hydroxycitric acid (HCA): Derived from the rind of the Indian Garcinia Cambogia fruit, hydroxycitric acid is used primarily as a "carb blocker" in weight loss products. Studies show HCA to be unimpressive for weight loss. A study published in the Journal of the American Medical Association (JAMA. 1998 Nov 11;280(18):1596-600) indicated that hydroxycitric acid has no positive weight loss effects, concluding...
  
  "Garcinia cambogia failed to produce significant weight loss and fat mass loss beyond that observed with placebo."
  
  There is hope for a newer form of HCA called SuperCitrimax (HCA-SX). A 2004 study showed supplementation with 4666.7 mg of HCA-SX (providing 2,800 mg HCA) was beneficial (see J Med. 2004;35(1-6):33-48). Evidently Xenadrine contains the superior form of HCA; HCA-SX.
  
  The Xenadrine advertising also references the combination of HCA and two other ingredients present in this formula (chromium polynicotinate and gymnema) to validate some of its claims. The good news is that there is a study (see Diabetes Obes Metab. 2004 May;6(3):171-80) validating the positive weight loss effects of this trio.
  
  This formula of Xenadrine contains pretty close to the amount of chromium polynicotinate used in this study, but because of the use of proprietary blends, it is impossible to determine for sure whether it contains equivalent amounts of gymnema. Xenadrine is definitely "light" on the HCA content, since a full day's worth of servings only delivers 3561 mg of the Lipo-Core™ complex—more than a 1,000 mg short of the 4666.7 mg of HCA used in the referenced study. And remember, Lipo-Core™ is not comprised of HCA alone; it contains 4 other ingredients (although likely only present in tiny amounts).
  
  
• Raspberry ketones: Similar in structure to capsaicin and synephrine—two compounds thought to enhance weight loss via the stimulation of norepinephrine (although real evidence to validate this theory is in short supply). One study performed on rodents (you can view the specifics of the study here) did show that raspberry ketones prevented fat synthesis as well as the rise of blood triglycerides and overall, helped prevent obesity.

  Of course, the problem is that this is an animal study. There is one pilot human study—likely conducted with 100 mg 2X/day (Integrity Nutraceutical's recommended dosage) that described the results thus...
  
  "During the Razberi-K trial, subjects showed a trend toward greater fat oxidation in the late stage." 
  
  That sounds a lot like saying the results weren't statistically significant to me. Regardless, it may be that raspberry ketones do show some promise, but a dramatic effect has yet to be demonstrated in any credible, independent human studies. Additionally, it's unlikely this product contains anywhere near an effective dose.

• Willow bark (salicin): In the old days, white willow was used as a natural source of salicin in the ECA (ephedra/caffeine/aspirin) stack. There's no evidence it provides similar, synergistic effects for ephedra-free products.
  
  
• Ginger root extract: Some small animal studies performed on zingerone (a component of ginger) have been positive for weight loss (Yakugaku Zasshi. 2008 Aug;128(8):1195-201) albeit the dosage used (170 mg/kg) is too high to be transferred into humans (a 180 lbs. person would need to take about 14 grams a day).

  Ginger also seems to accelerate gastric emptying... the opposite of the sort of thing dieters want (Eur J Gastroenterol Hepatol. 2008 May;20(5):436-40).

• L-Tyrosine: Because l-tyrosine is a precursor to the thyroid hormone thyroxine (also known as T4) supplementation may have a positive effect on thyroid hormone levels which may contribute to an increased metabolic rate. Many supplement retailers use the fact that tyrosine is a T4 precursor to make claims about its fat burning prowess.
  
  Unfortunately, clinical data validating l-tyrosine's thyroid-and-metabolism boosting characteristics is in darn short supply. In multi-gram doses (not present in this formula) its greatest demonstrated benefit is as a "mood elevator."
  

3) Thermodyne Complex™: A 462mg proprietary complex consisting of...

• Green tea extract (45% EGCG, 75% catechins, 90% polyphenols): One of the few "bright lights" for weight loss, green tea has several demonstrated effects beneficial for weight loss. Although the exact amount of green tea included in this formula is not revealed, we can assume there is slightly more than 200 mg here (ingredients are listed by dosage level, and the second ingredient, caffeine, is included at a dosage of 200 mg). That would mean there is slightly more than 90 mg of EGCG included per dose—an amount that corresponds to positive study data.
  
  
• Caffeine (anhydrous): On its own, caffeine is a decent thermogenic with demonstrated benefits for weight loss (see Am J Clin Nutr. 1989 Jan;49(1):44-50, Am J Clin Nutr. 1980 May;33(5):989-97), although some data indicates it offers greater benefits to lean individuals that those who are overweight (see Am J Physiol. 1995 Oct;269(4 Pt 1):E671-8). The combination of caffeine and green tea present here is a good one, and encourages even greater weight loss (see Obes Res. 2005 Jul;13(7):1195-204).
  
  
• Theobroma cacao, wasabia japonica, capsicum annum: With less than 62 mg left in this complex for these ingredients, it's pretty safe to say they are present as "label decoration" only. Not really an issue, since none have amazing fat burning characteristics.
  

4) Cytodrine™ Complex: A 137 mg proprietary blend of...

• Gymnema: Commonly used in fat burners for several reasons; it appears to inhibit the ability to taste sweetness (see Chem Senses 1999;24387-92) and inhibit the intestinal absorption of glucose as well as having an "anti-diabetic" effect (J Ethnopharmacol 1990;30:295-300). Animal studies even show gymnema may regenerate certain cells in the pancreas (J Ethnopharmacol. 1990 Oct;30(3):265-79).
  
  Of course, gymnema is also one of the three ingredients (in addition to HCA and chromium polynicotinate) that are referenced in the study featured on the Xenadrine web site (see Diabetes Obes Metab. 2004 May;6(3):171-80). This study used 400 mg of gymnema.
  
  A full, daily, 6-pill dose of Xenadrine contains 411 mg of the Cytodrine complex, which means it is possible that there is 400 mg of gymnema present. Of course, that means there's only 11 mg left over for the remainder of the ingredients here, meaning they will be present as "label decoration" only.
  
  
• Vitus vinifera (standardized for proanthocyanids): Basically, this is grape seed extract, which is a an extremely potent antioxidant. A good dose of grape seed extract is 50-100 mg per day. As previously discussed, if Xenadrine contains enough gymnema to make the above-mentioned study relevant, simple mathematics indicates there's not enough grape seed extract here to do anything but "spice up the label."
  
  
• Chamomile flower extract: An herb with mildly sedating effects, it's likely included here to offset the stimulating effects of this formula. However, I have my doubts that it's included in a dosage high enough to elicit any effect.
  
  
• Guarana seed: Included in fat burners for its caffeine content. Again, not enough here for anything but label decoration.

OK, there's the ingredient breakdown on the new Xenadrine formula. And, despite talk of "clinical strength", and "triple-action fat burning technology" this formula is not particularly revolutionary, nor does it utilize ingredients that haven't already been widely used in the supplement industry for years.

That is not to say this isn't a decent product.

It does contain green tea—standardized for the appropriate amount of essential catechins—and caffeine, a one-two combo that any decent product really should contain. And although I can't confirm it, I suspect it does contain pretty darn close to the correct amounts of two of the three ingredients (chromium polynicotinate and gymnema) referenced in this study. Unfortunately, it's a bit "light" on the HCA content (although it does contain the beneficial HCA-SX version), and it would be nice to see this addressed in an updated formula.

Nonetheless, both chromium and gymnema alone are decent additions to any fat burner, although neither delivers what can be described as "dramatic" benefits.

Xenadrine RFA-1 is not expensive (our recommended online retailer, BodyBuilding.com, sells 120 caps for just under $32), and the television advertising I've seen claims a 100% money-back guarantee. If this is the case (and I was not able to confirm the particulars of this "guarantee") the new Xenadrine RFA-1 is probably as good a product to experiment with as any.

As usual, don't expect miracles here—quality products can offer a boost here and there, but they won't work wonders on their own. You need to do your part, too.

The new version of Xenadrine RFA-1 is available from BodyBuilding.com, our recommended online retailer.

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