Diet Pills

Over-the-counter diet pills and supplements

Most diet pills on the market are not required to get pre-approval by the 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).

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 (a.k.a 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.

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.

Still, there is some evidence that controls for non-prescription diet pills are improving. According to Consumer Reports, as of December 2007 manufacturers of supplements and over-the-counter drugs are required to report adverse effects to the FDA within 15 business days. And starting in June 2008, more new regulations will take effect. These “good manufacturing practices” are designed to make sure supplements aren’t contaminated and don’t include the wrong ingredients. While they say the new rules are a step in the right direction, editors at Consumer Reports are skeptical about their effectiveness at curbing serious abuses such as the addition of unlisted prescription drugs.

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 weight loss supplements 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, publishing a report linking bitter orange to coronary angina. Health Canada has already reported 31 cases of cardiovascular adverse reactions linked to bitter orange. The two patients that reportedly died as a result had taken bitter orange in combination with ephedrine and caffeine. 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 "Dietary Supplements to Avoid." Bitter orange, germander and kava are on that list, along with nine 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. $30 for 60 tablets) 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, B-hydroxy-B-methylbutyrate, chitosan and CLA. 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). A May 2007 meta-analysis published in the American Journal of Clinical Nutrition says CLA does produce modest weight loss in humans when compared to a placebo and 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. $25 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. While DEX-L10 gets some excellent reviews on Drugstore.com from consumers who say the product has helped them, many users post that it doesn’t work and causes side effects ranging from headaches to stomach pain and nausea.

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, "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 seven 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 vs. 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. $25 for 30 tablets) , 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 on 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.

Prescription diet drugs

Research about prescription weight loss drugs is much more prevalent and credible due to the far stricter controls imposed on these drugs. At least there are long-term medical studies and FDA jurisdiction. However, just because these products have FDA approval doesn't actually mean they work -- or work without side effects that may render continued use unpleasant. Furthermore, the FDA's recent approval of orlistat (Xenical) for over-the-counter use has many watchdog organizations concerned.

The medications that are currently available for prescription weight loss are phentermine (under several trade names including Adipex-p, Obenix and Oby-Trim), sibutramine (Meridia in the U.S. and Reductil in Europe) and orlistat (Xenical). These medications are approved for people who are obese -- defined as having a body mass index (BMI) of 30 or more.

Another drug, rimonabant (sold in Europe as Acomplia) was to be sold in the United States under the trade name Zimulti. In June 2007, however, a 14-member FDA panel voted against its approval, saying manufacturer Sanofi-Aventis had failed to demonstrate the drug’s safety. Included in the hearing was testimony suggesting a link between rimonabant and an increased risk of depression, anxiety and suicidal thoughts. Sanofi-Aventis has since withdrawn its application to have rimonabant approved in the United States.

Do prescription diet drugs work? Here again, the answer isn't simple. In a WebMD study, obese people who modified their eating and exercise habits and took the prescription drug Meridia actually lost more weight than those who took the drug alone or those who only modified their eating and exercise habits. The group using Meridia in combination with diet and exercise lost an average of 26 pounds in a year. That breaks down to a weight loss of about two pounds per month -- that's about what fitness experts say you can expect from diet and exercise alone. Unfortunately, we have no idea what happened to the people in the study after they stopped taking Meridia.

Meridia affects a person's feeling of fullness, so they feel satisfied eating less food. It also prevents metabolism from slowing down even in the face of consuming fewer calories. Studies say the positive effects of Meridia tend to max out at six months and it can contribute to high blood pressure, which must be carefully monitored. Some doctors describe it as hit or miss. In outlining the pros and cons of Meridia in 2004, HealthFacts pointed to eleven clinical trials ranging from 12 to 52 weeks in which persons taking Meridia at varying doses lost an average of ten to 14 pounds over a year. Any weight loss is positive, of course, but that's roughly one pound per month. The article also points out that weight lost was regained when patients stopped taking the medication.

Orlistat (trade name Xenical) works by blocking fat absorption so that it moves through the intestine undigested. The idea of a fat blocker sounds good in theory until you consider the not-so-pleasant side effects, which include sudden diarrhea and "leakage." Those side effects go down as your fat intake does. Several articles we read suggested ironically that Xenical may work best as a deterrent, whereby eating less fat you have a reduced chance of nasty side effects. Clinically, Xenical produces similar results to Meridia, so we're talking about one pound per month on average over the course of a year.

In recent years, the consumer advocacy group Public Citizen has called for the FDA to pull both Meridia and Xenical from the shelves. In the case of Meridia, Public Citizen cites 49 deaths from cardiac arrest linked to the drug and 124 reports of cardiac problems developed by those taking the drug. With Xenical it is the threat of colon cancer that is cause for concern, as Xenical has been shown to increase aberrant crypt foci (ACF) cells in the colon in rats. ACF cells are widely thought to be a precursor to colon cancer. Xenical also has those aforementioned side effects that make the drug difficult for many people to tolerate. Consumer Reports has written articles about both medications and says you'd do better to stick with old-fashioned diet and exercise. The risks are not worth the relatively minor benefits.

The cross from prescription to over-the-counter is one that several drug companies are making an attempt to do. The recent FDA approval of Xenical for over-the-counter use (at 50 percent its prescription strength) has been eagerly anticipated by its makers for the past couple of years. Alli, as the OTC Xenical is called, has been selling well since it hit the shelves in June 2007. Though it is not intended for use by persons under the age of 18, and is meant to be used in conjunction with a reduced-calorie diet and exercise regimen, one wonders how the age recommendation will be monitored.

With the less-than-stellar clinical performance of Xenical in the eyes of many health experts, it's not surprising that much of the reaction to Alli's approval by the FDA was negative. Public Citizen called Alli's approval "reckless," and ConsumerAffairs.com's health advisors counsel caution. CNN's Dr. Sanjay Gupta issued a list of "10 things to think about before taking this drug," ending with, "Expect modest weight loss, and by the way, the weight loss plateaus after six months."

Since before Alli came on the market, its gastrointestinal side effects have been well publicized. In particular, some critics question the usefulness of a diet drug that can be tolerated by most users only in conjunction with a low-fat diet. GlaxoSmithKline gets around the issue by marketing Alli as part of a complete weight loss system incorporating the drug, a user support forum and an online program called "myalliplan." Because of Alli’s side effects (referred to as “treatment effects”), potential customers are warned to assess their level of commitment to a low-fat diet before they decide to use the drug. Those who do are encouraged to buy an Alli starter kit (*est. $45 to $120, depending on the number of pills) which includes a bottle of capsules, a carrying case, six information booklets and a code to access myalliplan.

Users posting to Amazon.com and Drugstore.com give Alli mixed reviews. While some dieters say the drug helps with weight loss, others say they find it ineffective. Even many of the most positive reviews mention the drug’s side effects. Several users say that the potential for oily spotting or other bowel issues helps them remember to keep the fat content of meals within the recommended limit of 15 grams. Others say they find the side effects inconvenient, embarrassing and even physically painful. One user points out that amount of fat typically blocked represents just over 100 calories a day, limiting Alli’s potential contribution to at best a pound of weight loss per month.

Mayo Clinic specialist Donald Hensrud, M.D.’s assessment is even more modest. He estimates that Alli could contribute to a weight loss of about three pounds a year to the eight pounds consumers could expect to lose through diet and exercise alone. He also advises users to take a daily multivitamin to help make up for the drug’s negative effect on absorption of fat-soluble vitamins like A, D, E, K and beta carotene.

The FDA's own approval statement for Alli is hardly a glowing endorsement: "We know that being overweight has many adverse consequences including an increase in the risk of heart disease and type 2 diabetes. OTC orlistat, along with diet and exercise, may aid overweight adults who seek to lose excess weight and improve their health." The FDA website lists the side effects for Alli and Xenical (orlistat) but mentions nothing of studies showing possible links to colon cancer. All things said, Alli is an over-the-counter weight loss aid for which we do have clinical data. Its known side effects have at least been documented. Still, diarrhea and flatulence are one thing, and an increased risk of colon cancer, if the Public Citizen's petitions are correct, is quite another.

Phentermine diet pills are the old-school appetite suppressants that have been around for years. They are chemically similar to amphetamines, or stimulants, that suppress the appetite and cause you to eat less. Back in the 80s, the combo Fen-Phen (phentermine plus fenfluramine) was thought to be a highly effective diet drug for a couple of years until studies linked fenfluramine to heart valve disease and the FDA asked that it be pulled from the market. On its own, phentermine can work to suppress the appetite and provide a short-term weight loss boost to obese persons. Phentermine is designed to be used in conjunction with a calorie-restricted diet and exercise regimen, and it's indicated for usage of less than 12 weeks. When taken for periods of longer than 12 weeks, phentermine can raise blood pressure and become addictive.

Surprisingly, there are not that many clinical studies of phentermine by itself, despite its having been around since the 1950s. Plenty of studies were done of the drug in combination with fenfluramine, but it was rarely studied on its own. In a study of 108 people by McMaster University, phentermine produced an additional 5.8 pounds of weight loss more than a placebo over a nine-month period. In a 2004 Korean study, phentermine produced an additional eleven pounds of weight loss as compared to a placebo over the course of a five-month trial. For someone who is clinically obese, phentermine combined with diet and exercise could be segued into a sustainable diet and exercise plan, but blood pressure and addictive response must be closely monitored by a physician.

Important Features: 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.

• Over-the-counter weight loss supplements (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.

• Prescription 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.

Sponsored links