A Look at What's In Weight Loss Supplements

Are these products helpful or harmful?


Turn on the TV or radio, browse the Internet or flip through a newspaper or magazine, and you’ll undoubtedly come across advertisements for weight-loss supplements. Their ads often lure you with promises of quick loss without dieting or exercising. However, often their claims are just that – claims – and are not supported by research.

Furthermore, because dietary supplements are not regulated the way medications are, they may have health risks that are not recognized until they are in common use. Ephedra, which used to be a common ingredient in weight-loss supplements, illustrates that all too well. The herb, also known as ma huang, is related to the hormone adrenaline and revs up the body’s systems. In doing so, it increases heart rate and blood pressure and can stress the heart and blood vessels, which has led to heart attacks and sudden death.

Because of the turmoil, ephedra products have been banned in the U.S. and other ingredients have taken ephedra’s place on the shelves.

Here are some commonly found ingredients in weight-loss supplements and what you should know about them. 

Bitter Orange

This ingredient contains synephrine. Because it is similar to ephedra both in chemical make-up and possible side effects, bitter orange should be taken with caution.


Processed from a protein found in the shells of insects and shellfish, chitosan packagers claim it keeps fat from being absorbed in the intestine. However, there is little research to demonstrate its effectiveness for weight loss. In one analysis of 15 studies with a total of 1,219 participants, researchers concluded that “chitosan may have a small effect on body weight but results from high quality trials indicate that this effect is likely to be minimal.”


A mineral claimed by some manufacturers to decrease blood sugar and help with weight loss, chromium has not been proven to have any positive effects. In one clinical trial comparing 1,000 micrograms of chromium picolinate daily to placebo in 80 overweight adults, there were no differences in weight loss between the two groups after 24 weeks.

Cider Vinegar

Thought to interfere with the digestion of carbohydrates, vinegar held down after-meal sugar spikes and was associated with moderate weight loss in two separate studies. But don’t run out for vinegar pills or capsules; it’s the active acetic acid in fresh vinegar that’s thought to have an effect on metabolism. Instead, have vinaigrette dressing or pickles with your lunch or dinner.


This tropical berry is loaded with caffeine – about 30 percent more than coffee. Some studies show caffeine increases metabolism, but not necessarily fat burning, and it tends to raise blood pressure. The safety of guarana is not well known.

Gymnema sylvestre

An extract from the leaves of this woody tropical plant from India is supposed to work as a “sugar destroyer.” But for weight loss, the evidence isn’t clear. In one study, people lost weight after eight weeks of taking a product containing Gymnema sylvestre, but the product also contained chromium and hydroxycitric acid. In addition, the subjects’ diets were limited to 2,000 calories per day and they participated in a walking program, so it’s not possible to say what caused their weight loss.

Hoodia gordonii Cactus

The flesh of this cactus-like plant is thought to suppress appetite. Interest in Hoodia skyrocketed following a 2004 “60 Minutes” report on the plant’s effects and continues to be a popular weight-loss ingredient. However, there is no reliable scientific evidence to support Hoodia’s use; and its potential risks, side effects, and interactions with medicines and other supplements have not been studied, according to the National Institutes of Health’s National Center for Complementary and Integrative Health (NCCIH). Furthermore, the quality of hoodia products varies widely, NCCIH reports.

Updated November 2015

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