Do Weight Loss Supplements Work?

Learn whether weight loss supplements actually work, and learn other ways you can maximize fat loss with diet.

Ben Greenfield,
August 30, 2010
Episode #018

From green tea to bitter orange, and from hoodia to heartleaf, herbal formulations and over-the-counter weight loss supplements are constantly being featured in advertisements online, on TV,  and on the radio, and also at your local gym, grocery store, and pharmacy. So do these calorie-burning cocktails actually work, or are they a waste of your money? In this article, you’ll find out what the research has to say about weight loss supplements and fat burning pills, and you’ll also learn how to maximize fat loss by choosing the right food.

What Are Weight Loss Supplements?

As you’ll learn later in this article, some foods can be considered weight loss supplements. But for the purpose of this discussion, a weight loss supplement is any pill, capsule, or tablet that includes herbal or chemical ingredients formulated specifically for the purpose of increasing your metabolism (allowing you to burn more calories) or decreasing your appetite (helping you take in fewer calories). In scientific literature, weight loss supplements are commonly referred to as thermogenic aids.

The poor performance of weight loss supplements when they aren’t paired with exercise, combined with the fact that I am the Get-Fit Guy and am supposed to be teaching you how to effectively enhance exercise, dictates that the remainder of this article will focus on giving you instructions for properly using weight loss supplements for workouts, and not for lounging on the couch while feasting on fat loss pills.

Do Weight Loss Supplements Work?

There have been many studies performed on weight loss supplements, although most of them were funded by the weight loss supplement industry. But the basic premise of these studies is fairly consistent: give a group of people a weight loss supplement, then measure the change in resting energy expenditure, or calories burned while sitting or lying down. The good studies go a step further and also measure the change in exercise energy expenditure, or calories burned during physical activity.

An Important Weight Loss Supplement Study

One of the most recent and comprehensive weight loss supplement studies to date was titled “Acute Effects of a Thermogenic Nutritional Supplement on Energy Expenditure and Cardiovascular Function at Rest, During Low-Intensity Exercise, and Recovery from Exercise.” In this study, researchers examined the effect of a weight loss supplement containing some of the most popular ingredients you’ll find in most weight loss supplements today:

  • caffeine,

  • capsaicin (a component of hot peppers),

  • bioperine (an extract of black pepper), and

  • big doses of niacin (vitamin B12).

The researchers gave men and women of average fitness this weight loss supplement and then measured their metabolism, blood pressure, heart rate, and their carbohydrate and fat burning for 50 minutes. They then measured all of these same variables during an hour of treadmill walking, and then measured them again during 50 minutes of post-exercise recovery.

Compared to a group that only took a placebo, the weight loss supplement group experienced a resting energy expenditure that was 6% higher, and a post-exercise energy expenditure that was 4-8% higher. Their maximum oxygen consumption during the exercise protocol was slightly higher, with a small but significant increase in lipid metabolism (fat burning) during exercise. But that’s not all--heart rate and blood pressure were also significantly higher during and after exercise in the weight loss supplement group.

Are Weight Loss Supplements Dangerous?

In a fantastic article on the Mayo Clinic web site, you can see a breakdown of popular weight loss supplements, including their ingredients, their claims, their effectiveness, and their safety. Unfortunately, based on clinical research, many of the supplements are reported as unsafe or banned by the FDA. In most cases, the reason for that is because of the same effects observed by the researchers in the study mentioned above: many weight loss supplements cause an increase in heart rate and blood pressure that can put the user at risk for dizziness, headaches, seizures, heart attacks, strokes, and even death.

That’s not meant to scare you away from taking any weight loss supplement. For example, green tea extract, chromium, and conjugated linoleic acid are all on the safer side of the Mayo Clinic’s spectrum. But any weight loss supplement that contains ingredients such as ephedra, high doses of caffeine, country mallow, or even orlistat (an ingredient in the weight loss supplement Alli) may put you at cardiovascular risk, damage your liver, cause gastrointestinal upset, or just make you feel downright jittery.

How to Take Weight Loss Supplements

Weight loss supplements are going to give the most benefit to a bodybuilder who wants to shed an extra 1% body fat, or to someone who needs just a little extra fat burning and already has a perfect exercise or diet routine.

It is important for you to understand that in the absence of exercise, most studies agree with the study described above, and show close to that figure of a 6% increase in resting energy expenditure after the use of a weight loss supplement, (and usually that effect only lasts for a few hours after taking the supplement). That means that if you’re burning 80 calories per hour at rest, which is pretty normal for the average person, and you’re not exercising after you take your weight loss supplements, you’re only going to increase your metabolism by about 4 or 5 calories per hour. To put this in context, in the absence of exercise, you would need to take a weight loss supplement for 35 consecutive days to lose 1 pound of fat. Without a weight loss supplement, you can achieve those same effects with just a few days of exercise!

In addition, the added calorie burn of 4-8% after exercise and the slight increase in fat burning during exercise would result in an extra fat burn for each hour of moderate exercise of around 30-50 calories, which is about half as much as the extra calories you can burn by doing 3-5 30 second bike or treadmill sprints after your workout. Considering that most weight loss supplements require an investment of a few dozen dollars a month, and in some cases hundred of dollars, the prospect of tacking on a bit of extra exercise instead of turning to weight loss supplements becomes quite attractive.

So if you are going to take a weight loss supplement, you need to not only realize that many of these supplements are dangerous, but also that the effects are significantly miniscule compared to exercise and eating healthy. And in most cases, you’ll see a very slight calorie burn when you take a weight loss supplement 60 minutes prior to exercise. That very slight calorie burn doesn’t hold a candle to the added calorie burn you’ll get when you follow a workout routine similar to the one I outline in the article “Which Workout Burns The Most Fat”.

What Should You Eat to Burn More Fat?

What about other weight loss supplements that I haven’t mentioned? You simply need to follow the rule of placing any weight loss supplement fat burning effect in proper context. Take fish oil, for example. In the most recent fish oil study, in which individuals exercised for 45 minutes per day while supplementing with 6g of fish oil for 12 weeks, the fish oil group lost 1.1% more body fat. But it turns out that they also consumed an average of 143 fewer calories per day, which means that over 12 weeks, they only lost 0.7 pounds more than the non-fish oil group.

In contrast, studies have shown that eating an extra 14 grams of fiber per day, which is the equivalent of a bowl of oatmeal with diced apples, may help you to lose an extra 4 pounds of fat in that same time frame! In her article, High-Fiber Foods, fellow Quick and Dirty Tips expert, Nutrition Diva, tells you about other good sources of fiber.


Aside from fiber, what are some other fat-burning foods that contain similar ingredients to supplements but won’t cost nearly as much? Look into jalapenos and chiles, which are a natural source of capsaicin; coffee, a natural source of caffeine; and regular green tea, full of epigallocatechin-3-gallate (EGCG), which the Nutrition Diva talks more about in her article on green tea. Also consider eating chicken, turkey, fish, and other lean sources of protein.

How Else Can You Easily Burn More Fat

In addition, standing rather than sitting can burn 50 extra calories per hour, pacing and twitching can burn 35-40 extra calories per hour, and laughing for 10 minutes can burn 40 extra calories per hour. Considering that standing to talk on your phone, tapping your feet, and watching a funny movie are far less expensive than weight loss supplements, you may want to think about this before forking over money for them (for more metabolism-boosting tips like this, you may also want to check out my book: “100 Ways to Boost Your Metabolism”).

So ultimately, weight loss supplements are going to give the most benefit to a bodybuilder who wants to shed an extra 1% body fat, or to someone who needs just a little extra fat burning and already has a perfect exercise or diet routine. But for the average person who needs to shed a few pounds, money would be better spent on a gym membership, running shoes, or a bicycle--and not on the overpriced weight loss supplement aisle of your local grocery store.

Pill image from shutterstock