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Ask a Pharmacist: The Skinny on Diet Pills for People with HIV

, by Jennifer Cocohoba, PharmD, AAHIVE

As summer begins, many people’s thoughts turn to shedding a few winter pounds. One of the questions I hear most frequently as the weather warms up is, “What pill can I take to help me lose weight?”

In this column, I will discuss a few popular drugs and supplements trending in weight loss—and whether they are safe options for people living with HIV.

The Missing Puzzle Piece

For HIV-positive people, one of the challenges in choosing a weight loss plan—whether it is a special diet, an exercise routine, medications, supplements, or a combination—is that most have not been studied in people with HIV. Many plans rely on herbs and dietary supplements—which are, by the way, reviewed by the U.S. Food and Drug Administration for safety, not for effectiveness—and fewer studies means there may be unknown interactions between weight-loss products and antiretrovirals that could potentially lower the effectiveness of the HIV medications or cause an increase in side effects.

This lack of information can be frustrating , but it doesn’t mean that weight loss medications and supplements are off-limits for people living with HIV. It does mean, however, that if you’re thinking about starting any weight loss medication or supplement, you should discuss it with your doctor and your pharmacist.

Your doctor can help you determine a safe weight-loss goal, and may refer you to a nutritionist. Prescription weight-loss medications are usually reserved for people whose weight has become dangerous to their health; your doctor will discuss with you the risks and benefits of prescription weight-loss medications in the context of your risk for heart disease, diabetes, bone disease, and other possible conditions that might not mix well with prescription weight-loss drugs.

Your pharmacist, in turn, may have special access to obscure information on drug-drug interactions, “natural” or complementary medicines, and supplements. If a weight-loss product is understudied but seems relatively safe, your doctor and pharmacist may give you the go-ahead to try it—but they may want to monitor your CD4 cell count and viral load more closely during that time to keep an eye on any changes in your immune health and response to your HIV treatment regimen. When everyone understands your goals, your health care providers can become an important part of your weight-loss team.

Hot Off the Shelves

If prescription weight-loss medications are reserved for serious cases of overweight and obesity, what is available to those who just want to lose a few pounds? Drug stores now carry fewer types of over-the-counter (OTC) weight-loss products than they did in the past. For example, fenfluramine, a medication that was part of the popular weight-loss drug Fen-Phen, was removed from the market in 1997 due to side effects on the heart valves and reports of pulmonary hypertension (high blood pressure in the lungs). Other formerly OTC drugs like phentermine (the other drug in Fen-Phen) and phenylpropanolamine have been moved to prescription-only status due to side effects. Ephedrine-containing products (often derived from plants in the genus Ephedra) were removed from the market in the mid-2000s for safety concerns about stroke and heart attack.

So what is left on drug store shelves? In many currently available OTC weight-loss medications, the primary active ingredients are caffeine, mild diuretics, and high-fiber substances.

There are many theories about how caffeine might help with weight loss, including acting as a diuretic (stimulating water loss from the body), suppressing appetite, or enhancing thermogenesis (promoting calorie burning). Clinical studies looking at caffeine for weight loss are generally small or poorly conducted, or are performed only in animals, making it difficult to apply the results to humans. As enticing as it may sound to slim down while sipping iced coffee, studies generally do not demonstrate a strong link between caffeine and long-term weight loss.

Be sure to read medication and supplement labels closely. Even though the label of a product promising weight-loss benefits may not declare caffeine as one of its ingredients, it may list extracts from plant sources; for example, green tea extracts contain caffeine. If you are sensitive to caffeine, be mindful of this when reading labels. A cup of coffee typically contains about 80 to 130 mg of caffeine. The dose of caffeine contained in many weight-loss supplements is the equivalent of drinking two or more cups of coffee.

As Seen on TV

Popular examples of weight-loss products marketed on television include drugs like Lipozene, Hydroxycut, and Xenadrine. These medications are not typically bought from a pharmacy but are ordered directly from the manufacturer or online. Manufacturers’ websites usually contain information about the herbs, vitamins, and supplements contained in these products.

Again, before sampling a weight-loss aid purchased online or outside a pharmacy, talk with your medical team about any possible side effects or risks specific to your individual health.


The active ingredient in Lipozene is glucomannan, which comes from the root of the konjac plant. Glucomannan is a polysaccharide (combination sugar) composed of two sugars—glucose and mannose—and fiber. It is not absorbed by the body. The fiber absorbs water and may make you feel full, causing you to want to eat less.

Does it work? Studies of glucomannan for weight loss are limited; however some benefit has been seen. For example, a 2005 review of studies assessing glucomannan for weight management attested that the supplement was “well-tolerated and resulted in significant weight loss in overweight and obese individuals.”

Is it safe for people with HIV? Glucomannan has not been assessed specifically in HIV-positive people. However, it is known that excess dietary fiber can block drugs from being absorbed in the gut, so any HIV medications should either be taken one hour before or four hours after taking Lipozene. Consuming too much fiber can also cause intestinal blockage, so it must be taken with plenty of water.

Hydroxycut and Xenadrine

There are several different formulations of Hydroxycut. Most contain some amount of vitamin C and various substances thought to be antioxidants, such as acai berry and pomegranate. The active weight-loss ingredients listed in most Hydroxycut formulations are caffeine and various herbs and spices that may act as mild diuretics to promote water loss.

In 2009, the FDA issued a Consumer Update warning of 23 reports of health problems related to liver damage—including one death from liver failure—in people taking some Hydroxycut formulations. These reports are of particular concern to people who have coinfection with HIV and hepatitis C virus, which causes liver damage, and anyone else with liver disease.

Similar to Hydroxycut, formulations of Xenadrine contain caffeine as well as herbs with diuretic properties. The original formulation of Xenadrine also contains white willow bark, which is the plant that aspirin is derived from. An earlier formulation contained ephedrine, and gained notoriety in 2003 when it was implicated in the heat stroke death of Baltimore Orioles’ pitcher Steve Bechler, and in a fatal car crash involving a driver with a pre-existing psychiatric condition. Ephedrine no longer appears in the Xenadrine ingredients list.

The FDA in 2004 sent letters to two manufacturers of Xenadrine, claiming the companies had overstated the effectiveness of their products. “We have reviewed these claims and have concluded that they are not supported by competent and reliable scientific evidence,” the FDA letters said.

The Wizard of Oz

Many of my HIV-positive clients watch the Dr. Oz Show on TV and are curious about the supplements he has discussed for weight loss.

On his show, Dr. Mehmet Oz has recently covered different types of fiber supplements. One is the PGX Fiber Supplement, and another is konjac fiber, the same active ingredient found in Lipozene. These supplements contain plant fibers that are not absorbed by the body. Rather, the idea is that the fiber absorbs water, swells up, and helps you feel full so you eat less.

Does it work? “The consumption of PGX in concert with lifestyle modifications may be a useful strategy for weight loss in overweight and obese individuals,” concluded a small 2010 study, which saw significant reductions in weight, waist circumference, and body fat percentage in people who took the supplement two or three times daily for 14 weeks.

As with Lipozene, any fiber supplement should be taken with plenty of water, and people with HIV should take them separately from antiretroviral medications.

Dr. Oz has also discussed raspberry ketones for weight loss. The active component of raspberry ketone has a structure that is similar to capsaicin—the chemical that gives spicy peppers their “heat”—and to synephrine, a stimulant that constricts blood vessels. There is very little evidence about the effectiveness or the safety of raspberry ­ketones for weight loss because most studies have been conducted only in animals. The exact mechanism of action is unknown, but raspberry ketones are thought to affect adiponectin, a protein that is responsible for regulating sugars and fat in the body.

Another recently discussed weight loss aid, L-carnitine, is available as a supplement but also ­occurs naturally in the body. It plays an important role in producing energy in cells. There have been some preliminary clinical studies in humans where L-carnitine seemed to improve energy for some patients with cancer or other diseases.

Dr. Oz has also recently discussed white kidney bean extract, also known as bean pod. The pod, which contains fiber, has been hailed as an active component for weight loss. It is also touted as a “starch blocker,” although one study in humans found that white kidney bean extract did not appear to block starch absorption, as measured in stool samples and blood glucose and insulin levels.

Two clinical studies of white kidney bean extract have been conducted in humans. One randomized study of 25 people assessed 1,000 mg of white kidney bean extract in combination with a modified diet and exercise over four weeks and found increased weight loss in the bean group compared to those taking placebo (6.0 pounds vs. 4.7 pounds lost). Another randomized study of 50 obese individuals compared white kidney bean extract versus placebo (without any diet or exercise plan) over eight weeks and also found a weight-loss difference between the bean and placebo groups (3.79 vs. 1.65 pounds lost). However, in both studies the differences were not statistically significant.

No Magic Pill

Despite all of these options, there is no readily available “magic pill” that can do all of the work required for sustained, healthy weight loss. Most experts agree that the most effective plans aim for gradual and careful weight loss, and include several different elements such as adjustments in diet and tailoring an exercise plan to improve strength and calorie-burning.

If you’re thinking about starting an OTC medication or supplement as part of your weight-loss plan, be sure to involve your whole health care team. There may not be much information on the products you want to use, but your health care team can try their best to find answers for you, help you weigh the risks and benefits of using a product, and monitor your labs so that you are able to achieve your summer weight-loss goals and keep your HIV under control.

Selected Sources and Further Reading

Celleno, L. and others. A dietary supplement containing standardized Phaseolus vulgaris extract influences body composition of overweight men and women. International Journal of Medical Sciences 4(1):45–52. January 24, 2007.

The Dr. Oz Show. The Weight Loss Center. Available at http://www.doctoroz.com/diet-and-weight-loss-center.

Gregory, P. (editor). Natural Medicines Comprehensive Database. Stockton, CA: Therapeutic Research Faculty, 2012. Also available at http://www.naturaldatabase.com.

Keithley, J. and B. Swanson. Glucomannan and obesity: a critical review. Alternative Therapies in Health and Medicine11(6):30–4. November–December 2005.

Lyon, M. and others. The effect of a novel viscous polysaccharide along with lifestyle changes on short-term weight loss and associated risk factors in overweight and obese adults: an observational retrospective clinical program analysis. Alternative Medicine Review (1):68–75. April 15, 2010.

Manore, M. Dietary supplements for improving body composition and reducing body weight: Where is the evidence? International Journal of Sport Nutrition and Exercise Metabolism 22(2):139–54. April 2012.

The Mayo Clinic. Weight loss. Available at http://www.mayoclinic.com/health/weight-loss/MY00432.

O’Brien, K. and others. Progressive resistive exercise interventions for adults living with HIV/AIDS. Cochrane Database of Systematic Reviews (4): CD004248. October 18, 2004.

Udani, J. and B. Singh. Blocking carbohydrate absorption and weight loss: a clinical trial using a proprietary fractionated white bean extract. Alternative Therapies in Health and Medicine 3(4):32–7. July–August 2007.

U.S. Federal Drug Administration. Dietary Supplements. Available at http://www.fda.gov/Food/DietarySupplements/default.htm.




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