Are Diet Pills Safe?

Safety of over-the-counter diet pills

Most diet pills on the market are not required to seek 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, over-the-counter diet pills are not regulated and are not required to prove their marketing claims or efficacy. Unfortunately, many Americans believe they are. Out of 3,500 adults surveyed by The University of Connecticut's Center for Survey Research and Analysis (CSRA) in 2006, 54 percent responded that they believe over-the-counter diet pills are approved by the FDA. 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 (also known as 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 manufacturer 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 ConsumerReports.org, 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. In June 2008, more new regulations took 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 ConsumerReports.org are skeptical about their effectiveness at curbing serious abuses such as the addition of unlisted prescription drugs.

Potentially dangerous weight-loss ingredients

In recent years, the FDA has issued warnings about several of the ingredients contained in many diet pills, namely 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 known as citrus naringin, bitter orange works similarly to ephedra by increasing heart rate and constricting blood vessels. Scientists warn that using bitter orange with caffeine can heighten these effects. The Mayo Clinic links bitter orange to high blood pressure and dangerous heart arrhythmias, and a 2006 study conducted at the University of California, San Francisco, showed that even one dose of bitter orange can cause side effects. Researchers gave 15 healthy adults a single dose of a bitter orange supplement, and participants registered increases in heart rate and blood pressure for five hours after taking the supplement. In addition, 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 there are too many reports of adverse effects.

ConsumerReports.org clearly favors a cautious approach, publishing a list of dietary supplements to avoid. Bitter orange, chaparral and kava are on that list, along with eight others. Their bottom line is that no weight-loss supplement or diet pill can be considered safe, and therefore all should be avoided. Researchers at Harvard Medical School agree, publishing an article in American Family Physician that looks at 21 weight-loss supplements, none of which are recommended. Overall, they say use of chitosan, ephedra-like chemicals with caffeine, guar gum and spirulina should be discouraged; the rest they urge to be taken with caution.

Usnic acid

Usnic acid has been linked in studies to acute liver toxicity and even death. In a 2003 article, The New York Times printed an article about Jennifer Rosenthal, a 28-year-old mother who took a diet pill containing usnic acid. For 17 days, Rosenthal took half the maximum dose. She ended up in the hospital with acute liver failure and required a liver transplant. Usnic acid is found in diet supplements like Lipolyze, manufactured by Species Nutrition. The Memorial Sloan-Kettering Cancer Center says, "No scientific evidence supports the use of usnic acid for weight loss. Supplements containing usnic acid are associated with severe liver toxicity."

Kava

Kava supplements are widely available on the Internet -- marketed either for weight loss or anxiety relief -- even though the FDA warned in 2002 that kava kava has been associated with liver toxicity. Incidentally, kava kava supplements were banned in 2002 by Germany and Canada.