Over-The-Counter Diet Pills

No support for diet pills using bitter orange

The makers of CortiSlim tell us that the stresses of life cause our bodies to release too much of the hormone cortisol, which prompts us to store fat. CortiSlim is supposed to counter this effect. There are a couple of problems here, according to research. First, there is no evidence that cortisol is responsible for fat storage or that cortisol levels fluctuate very much. Katherine Zeratsky with the Mayo Clinic says there is "no reliable evidence that so-called cortisol blockers such as CortiSlim, CortiStress or Cortistat-PS will lead to weight loss." Secondly, there are no double-blind placebo studies to show that CortiSlim diet pills are effective at depressing cortisol levels and producing weight loss. The FTC charged the makers of CortiSlim with making false claims about its ability to cause rapid, sustainable weight loss, and the manufacturer was hit with some hefty fines. In 2009, CortiSlim relaunched its formula with a focus on bitter orange -- the ephedra-like ingredient that is deemed potentially dangerous by many health experts.

TrimSpa X32 was endorsed by the late celebrity Anna Nicole Smith and featured testimonials saying that she'd lost 69 pounds in eight months using TrimSpa. Like CortiSlim, TrimSpa was found to have unsubstantiated weight-loss claims by the FTC. The FTC also pointed out that the claims for its appetite-suppressing ingredient, hoodia gordonii, are largely unproven. In addition to hoodia gordonii, TrimSpa diet pills contain chromium, vanadium, glucomannan (fiber), citrus naringin (bitter orange), glucosamine HCL, cocoa extract and green tea extract, many of which are stimulants. Independent testing conducted several years ago by ConsumerLab.com showed that TrimSpa X32 contained significantly more chromium than stated on the label, in amounts that can be toxic for the kidneys or liver. A 12-week study on 88 women conducted by the Human Nutrition Research Center at the U.S. Department of Agriculture found that chromium supplements "did not independently influence body weight or composition."

In the case of Xenadrine EFX, the FTC says that placebo pills produced greater weight loss in one clinical trial than the supplement. Some of the Xenadrine advertising showed customers who claim to have lost anywhere from 20 to 110 pounds while on the diet pills, but the FTC says that these people actually "engaged in rigorous diet and/or exercise programs in order to lose weight, and some were provided with a personal trainer," in addition to a fee ranging from $1,000 to $20,000 for their endorsements. As with the rest of these diet pills, it's unclear whether Xenadrine will work, and what we read to the contrary concerned us.

A 2004 article from ConsumerReports.org highlights the case of a woman who suffered seizures while taking Xenadrine EFX diet pills, a reaction that her doctors believed was triggered by bitter orange in the supplement (bitter orange is also an ingredient in TrimSpa and CortiSlim). Xenadrine EFX also contains large amounts of caffeine -- when ConsumerLab.com tested the supplement, they found 448 mg of caffeine in a daily dose. They note that caffeine consumption over 300 mg has been linked to heart palpitations, and experts warn against consuming bitter orange and caffeine together. As part of its settlement with the marketers of Xenadrine EFX, RTC Research & Development, the FTC held a campaign in the summer of 2007 to inform dissatisfied customers of their right to request a refund. Since then the company's website has been removed, but Xenadrine EFX can still be purchased through a number of online retailers.

Scant support for conjugated linoleic acid (CLA)

In a review of diet-pill ingredients, the Mayo Clinic states that conjugated linoleic acid (CLA) is the only ingredient that may lead to fat loss, but it's unlikely to reduce total weight and its long-term effects are unknown. CLA is a fatty acid that is naturally found in foods, including beef and dairy products. It has been marketed for fat loss since the 1990s, and is the main ingredient in a number of supplements, including GNC Pro Performance Maximum CLA and Source Naturals Tonalin CLA. While you can find dozens of weight-loss supplements touting the fat-burning potential of CLA, studies on its effectiveness have varied over the years.

In a 24-month study of CLA published in the April 2005 Journal of Nutrition, subjects taking the supplement did lose a significant amount of body fat, but they also increased their risk of heart disease and stroke. However, when CLA was studied in mice, they developed dangerous fatty deposits in their livers, although that result was not duplicated in rats. Both studies were conducted at Ohio State University. Other studies have indicated that CLA supplements could lead to insulin resistance. However, ConsumerLab.com, which tests a number of CLA supplements, says CLA is "generally safe in healthy individuals."

A new study, released in July 2009, has attracted attention for showing that CLA supplements may lower BMI and reduce body fat in obese women. The study, which was conducted at Ohio State University and published in the American Journal of Clinical Nutrition, tracked 35 post-menopausal women who kept their exercise and eating habits the same, but took 1 2/3 teaspoons of CLA each day. After 16 weeks, the women had lost between 2.3 and 3.5 pounds of body fat. The researchers concluded that CLA "may be beneficial for weight loss, glycemic control or both." The study did receive a "monetary gift and dietary oils" from Cognis, although the study states that Cognis had no input into the study design or conclusions. Cognis is the manufacturer of Tonalin CLA, which is sold in supplement form under dozens of brand names, including Natrol and VitaminWorld. The consensus seems to be that CLA supplements may lead to a few pounds of fat loss, but more study is needed to determine the long-term safety of these pills.

Hoodia doesn't have much support either

The jury is still out on hoodia gordonii, harvested from a cactus-like succulent in Africa, but most experts say there is no evidence to support any weight-loss claims. Right now, hoodia simply does not have credible medical studies to back it up. Two reputable organizations, ConsumerReports.org and ConsumerLab.com, do not recommend hoodia for weight loss. The National Institutes of Health says there is "no scientific evidence to support hoodia's use. No studies of the herb in people have been published." Public Citizen says hoodia diet pills are just "the latest in a string of diet pill scams." In addition, reports indicate that many hoodia diet pills don't actually contain hoodia gordonii, and the safety of these supplements has not been proven.

Manufacturers point to a couple of studies in support of hoodia, including a Brown University study published in the September 2004 issue of Brain Research. In the study, injecting the pure P57 hoodia gordonii molecule into the brains of rats caused them to eat less. Another often-cited study is a 2001 study commissioned by the British company Phytopharm, which found that 18 people taking hoodia gordonii supplements (while also on a reduced-calorie diet and exercise regimen) consumed 1,000 fewer calories per day. That's a pretty small study, and it was not published or subjected to peer review, but Phytopharm felt confident enough in the promise of hoodia to partner with Unilever and embark upon a five-stage clinical trial of its efficacy and safety. While the results of that study are not known, it apparently didn't go well -- Phytopharm and Unilever terminated their agreement to develop a Hoodia weight-loss supplement in December 2008, and a spokesman for Unilever said hoodia "cannot meet our high standards for safety and efficacy."

Plenty of other companies market their own versions of hoodia diet pills, including HoodiTrim, Super Hoodia 2000 and Hoodia Diet Max. Experts caution that hoodia is often combined with stimulants like bitter orange, green tea and caffeine, which can increase the possibility of side effects. Overall, experts say hoodia won't help you lose weight.

7-Keto DHEA Diet Pills

Lean System 7 is one of the few diet pills that's been subjected to a clinical trial. Two studies indicate that 7-keto, a metabolite of dehydroepiandrosterone (DHEA) and the main ingredient in Lean System 7, may have an effect on body weight. That said, both of the studies were short (only eight weeks), only 30 people completed each one, and they were financed by the manufacturer.

The Minnesota Applied Research Center conducted a trial on 7-keto, which was published in the February 2005 issue of the journal Nutrition. This randomized, double-blind, placebo-controlled study found that participants who took three capsules of Lean System 7 twice daily had significantly increased their resting metabolic rate (RMR) by 7 percent, as compared to the placebo group, whose RMR had slowed by 0.7 percent. However, the study was paid for and commissioned by iSatori Global Technologies, the manufacturer of Lean System 7. An earlier study, published in 2002 and conducted by the same researchers, looked at the ingredient 7-keto in a product called "7-Keto Naturalean" as compared to a placebo. The study of 35 participants found that 7-Keto Naturalean, combined with a reduced-calorie diet and an exercise program, resulted in a significant weight loss compared with diet and exercise alone.

It's hard to test the long-term safety and efficacy of a supplement in eight weeks, and critics worry that these supplements have not been proven safe. Lean System 7 contains bitter orange, a stimulant that contains synephrine -- a chemical similar to that found in the now-banned ephedra. The Mayo Clinic recommends against its use, and the National Institutes of Health says bitter orange "may not be safe to use." Public Citizen recommends against using any dietary supplement that contains bitter orange, which would include Lean System 7.