Most non-prescription diet pills sold are not required to get pre-approval by the US Food and Drug Administration (FDA) due to the wording of the 1994 Dietary Supplement Health and Education Act (DSHEA), which basically treats weight loss supplements as food. In short, they are not governed as drugs that require FDA approval. And, unfortunately, 54 percent of people surveyed by The University of Connecticut’s Center for Survey Research and Analysis (CSRA) believe that they are. Currently, Alli (the prescription drug Xenical at 50 percent strength) is the only over-the-counter weight-loss pill to be approved by the FDA, and even that has some very unsavory side effects coupled with questionable success (as discussed further below).
Non-Prescription Diet Pill Safety Standards
The passage of the Dietary Supplement Health and Education Act established a separate safety standard for dietary supplement ingredients, but only if the ingredient is new to the market. Therefore, supplements in existence before 1994 are automatically considered safe until found otherwise. Under DSHEA, it falls to the FDA to prove that these diet pill supplements are dangerous, rather than the company bearing the burden of proof. Ephedra (aka ma huang) is an excellent case in point, as it took the FDA eight years to compile enough evidence against ephedra to ban it from weight loss products in 2004 (it first issued an ephedra warning in 1996). The resulting lawsuit brought against manufacturers of ephedra diet products has led to a $34.2 million settlement. For more information please read about the Ephedra Ban.
So, if a diet pill introduces a new ingredient, the FDA will take a look at it before it goes on sale. Otherwise they are left to wait and see if the pills produce “adverse results” before taking any regulatory action. In the meantime, the FDA can issue press releases, which the public may or may not be aware of.
Long-term medical studies are the only way to judge the efficacy of a weight loss strategy, and while we did find some long-term studies of prescription diet drugs, medical studies backing up non-prescription diet pills are few and far between. Even when we found a published, double-blind placebo study for one diet pill — Lean System 7 — it turned out that the study had lasted only eight weeks.
The much-hyped hoodia gordonii has only an unpublished manufacturer-financed study from 2001 that included 18 participants in Great Britain and a study on the brains of rats to back up its efficacy claims. No prescription product would get near the shelf with a resume like that, but because hoodia is a supplement, it’s not subjected to the rigorous approval processes established by the FDA for prescription diet drugs.
The Consumer Reports bottom line on hoodia is that there’s no reason to believe it will work and not enough study to know if it will hurt you. That’s an opinion shared by nearly all of the credible reviews we found. But hoodia is hardly the exception to the rule. In recent years, the FDA has issued press releases about several of the ingredients contained in many diet pills, namely the ephedra-cousin bitter orange, found in TrimSpa and CortiSlim, the herb kava (sold as an herb by that name or Kava Kava), and usnic acid, found in some bodybuilding formulations.
Bitter orange (also listed as citrus naringin) works similarly to ephedra by increasing heart rate and constricting blood vessels. Scientists also warn that using bitter orange with caffeine can heighten these effects. Plenty of diet supplements combine the two in order to enhance the stimulant effect. Usnic acid has been linked in studies to acute liver toxicity and possibly a death. Kava has also been tied to multiple cases of liver failure and one death in the U.S. At present, these supplement ingredients are “under investigation” by the FDA. A warning was issued against kava in 2002, but presumably the FDA has not amassed enough evidence to take it out of circulation. Incidentally, kava is banned in a host of other countries, including Canada and Singapore.
The FDA’s website isn’t very user friendly, making it difficult to ascertain where they are in their research efforts. The Mayo Clinic is more forthcoming with their data, recently publishing a report linking bitter orange to coronary angina. Health Canada has already reported 16 deaths linked to bitter orange. New York Senator Chuck Schumer called for the ephedra ban to extend to like products, including bitter orange and usnic acid, when the FDA ephedra ruling originally came into effect in 2004. A January 2007 article in Clinical Advisor tells doctors not to recommend bitter orange for weight loss, saying there is scant evidence that bitter orange is effective and that there are too many reports of adverse events related to its usage. A 2006 report from The Mayo Clinic cites kava, germander, ephedra and LipoKinetix (a multi-ingredient diet product containing usnic acid) and usnic acid alone as all causing acute liver injury. LipoKinetix has since been voluntarily pulled from the market by its distributor.
Consumer Reports clearly favors the “better safe than sorry” approach, publishing a hit list of “12 Supplements to Avoid.” Bitter orange, germander and kava are on that list, along with green tea extract and seven others. Many of the ingredients on Consumer Reports’ list are found in a myriad of diet supplements. The Consumer Reports bottom line is that no weight loss supplement or diet pill can be considered safe and therefore all should be avoided. A 2004 report by Harvard Medical School would appear to agree with Consumer Reports’ findings, as its assessment of 21 weight-loss supplements results in a clinical stance of “caution and monitor” for 17 of them, and “discourage” for the remaining four. None of the diet pills are found to be effective and worthy of recommendation at all.
Consumer Lab’s investigation adds more fuel to the fire. Consumer Lab breaks down eleven diet pills to find that only six live up to their label claims. Several of the diet pills taken into the lab are found to contain ingredients not listed on the label. Two of them, including Lean System 7 (*est. $40 for one-month supply), receive warnings for combining bitter orange with caffeine. A product called Rainbow Light Garcinia-Max Diet System (*est. $20 for 20-day supply), is found to be contaminated with lead, and Pinnacle Pyruvate 1000 Bioactive Fat Modulator (*est. $25 for one-month supply) is tossed from the study because the pill did not break apart properly.
Are there any safe diet pills that work?
The short answer is that it’s just impossible to tell. Without the long-term medical studies to back them up, these diet pills are being sold with little regulation and accountability. A 2001 study in Critical Reviews in Food Science and Nutrition reviewed 15 diet supplements and found five that might hold some promise with further study: pyruvate, DHEA (7-keto), B-hydroxy-B-methylbutyrate, chitosan and CLA (conjugated linoleic acid). That same study concludes that only one supplement mix was proven effective for weight loss — the ephedra-plus-caffeine combo that we now know to be dangerous. Additionally, the 2004 Harvard Medical School report stated that chitosan had no discernible effect on weight loss and discouraged its use.
In the longest trial we found for a diet pill, a 24-month study of the ingredient CLA reported 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. The commercial product Tonalin CLA was studied for 12 months in Norway, resulting in a five-pound body-fat loss for those taking Tonalin CLA versus a one-pound gain for those taking the placebo. However, when CLA was studied in mice and rats, the mice developed dangerous fatty deposits in their livers (the rats, however, did not). CNN gives CLA a thumbs-up in its list of “6 promising supplements, 6 to avoid”, but it seems like there’s reason enough to avoid it for now. And there is also disagreement among other experts. The consensus seems to be that more study is needed to determine definitively whether CLA is in fact safe and effective. Even if the FDA has its hands tied by bureaucracy, it’s disheartening to read that products remain on the shelves containing ingredients that the Mayo Clinic, Consumer Reports, Harvard Medical School and Public Advocate tell us may not be safe.
The jury is still out on hoodia, harvested from a cactus-like succulent in Africa. There are not enough studies to prove or disprove its efficacy, and right now, hoodia simply does not have what experts consider credible medical studies to back it up. Two reputable organizations, Consumer Reports and ConsumerLab.com, do not recommend hoodia for weight loss. To put things in perspective, at the very best, hoodia might eventually turn out to be an effective appetite suppressant — but certainly no wonder diet pill. At worst, hoodia will be found to be ineffective and dangerous to your health.
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 the rats caused them to eat less. Another often-cited study is a 2001 study commissioned by the British company Phytopharm, which apparently 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. This will be the first long-term medical study that has weighed hoodia as an appetite suppressant in human beings. So Phytopharm, the company that started all the hoodia hoopla, has yet to release its own hoodia gordonii products.
Plenty of other companies have jumped on the early research to forge ahead. All reviews, negative and positive, stress that there’s no hope of reaping hoodia’s potential benefits unless you are taking hoodia gordonii, a specific variety of hoodia. How do you know if you’re getting the real hoodia gordonii? A 100 percent hoodia gordonii supplement should have certificates of authenticity to back it up, which are required for exporting hoodia gordonii from South Africa. A chemical analysis report should verify that the supplement contains hoodia gordonii. When it comes to dosage, there is no real consensus. Erring on the side of safety, the editor of the Hoodia Info Blog advises taking the least daily recommended dosage of a 100 percent pure hoodia gordonii product, and obviously checking with your doctor before taking it at all. Experts caution that hoodia is often combined with stimulants like bitter orange, green tea and caffeine, which should be avoided. If you do go the hoodia route, make sure it’s 100 percent hoodia gordonii powder without any fillers or other herbs mixed in. DEX-L10 Hoodia Gordonii Natural Appetite Suppressant (*est. $30 for 60 capsules) is one of the few products that is 100 percent hoodia gordonii, with the authenticity certificates to prove it and nothing else added.
Lean System 7 (*est. $40 for one-month supply) is one of the few diet pills that’s been subjected to credible clinical trials. It has two double-blind placebo studies confirming the efficacy of its magic ingredient, 7-keto, a metabolite of DHEA. That said, both of the studies were short, only eight weeks, with only about 30 people completing each one.
The Minnesota Applied Research Center conducted a trial, the “Effect of Lean System 7 on metabolic rate and body composition,” published in Nutrition Magazine, February 2005. This randomized, double-blind, placebo-controlled study took healthy overweight adults and gave them either three capsules of Lean System 7 twice daily or an identical dosage of a placebo for eight weeks. The participants followed a calorie-restricted diet and an exercise program. At the end of eight weeks, those taking Lean System 7 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. The Lean System 7 group had also decreased their hip circumference by a greater amount than the placebo group (3.78 cm v. 2.07 cm). Seasoned dieters know that with weight loss comes a drop in metabolism, so the fact that Lean System 7 appears to actually achieve the opposite result, raising the body’s RMR, is significant. An earlier eight-week double-blind placebo trial, published in 2002, 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 (*est. $35 for one-month supply) combined with a reduced-calorie diet and an exercise program resulted in a significant weight loss compared with diet and exercise alone.
Though both of the eight-week studies ended without adverse results, critics of the supplement worry that its long-term safety and efficacy are not conclusively known. A look at the bottle reveals that it contains bitter orange, a stimulant against which several of our most credible sources advise caution. It also groups green tea extract, guarana and yerba mate, all of which are stimulants in varying forms. In short, this supplement packs in a powerful punch with caffeine-like ingredients that could spell trouble for cardiac health in the long term.
If their findings don’t all gel, experts can at least agree on the need to alert your doctor before sampling any weight loss supplement, and the fact that none of these supplements have been proven to work unless subjects made changes in their diet and/or exercise habits. In the long-term medical studies that we saw for diet supplements and drugs, the pills were always used in conjunction with a reduced-calorie diet.
What You Need to Remember When Buying Diet Pills
- Despite the hype about diet pills, most experts say that calorie reduction and exercise are the best way for most people to lose weight. Prescription diet drugs are only recommended for obesity, and weight loss supplements show little if any benefit at all. See our report on weight loss programs for some behavioral and nutrition options.
- Non-prescription diet pills (with the exception of Alli) are not subject to approval by the FDA. That means that they are almost entirely unregulated, and manufacturers freely make inflated or fraudulent claims, as demonstrated in the recent FCC settlement against the makers of CortiSlim, Xenadrine EFX, TrimSpa and One-A-Day Weight Smart.
- Diet drugs should only be used in close consultation with your physician. If you are wondering whether a diet drug is an option for you, talk to your doctor. In a survey conducted by the University of Connecticut’s Center for Survey Research & Analysis (CSRA) of 3,500 Americans, only one-third of overweight people consulted their doctor about their concerns.
Prescription Weight Loss Medications
In addition to drugs marketed for weight regulation, there exist a host of prescription drugs whose primary indication is not weight loss, but which produce weight loss as a side effect. As doctors become more creative and scientists understand more about how the human brain works, patients are increasingly trying “cocktails” of drugs that may help to regulate their weight. These can include antidepressants, anti-seizure drugs, drugs for attention deficit disorder and for smoking cessation, diabetes and sleep disorders, and opiate overdoses. Some of these medications are especially helpful when it comes to very specific problems like nighttime eating syndrome, for which the anti-seizure drug Topamax is often prescribed.
Weight Loss Using Diet Pills
The vast majority of experts say the best way to lose weight is through behavior modification through diet and exercise. See our report on weight loss programs for the best diet plans.