Do Weight Loss Supplements Really Work? Here's the Truth

Uncover the facts about common weight loss supplements, including which ones might actually work and which ones have little effect.

Published November 17, 2022
Handful of Vitamins

Let's talk about weight loss supplements. You've probably seen those appealing ads as you scroll through your Instagram feed or shop online. You know the ones: they tell you that weight loss is no problem at all as long as you buy the right product. All you have to do is take this pill or chug that drink and the pounds will magically slide off. Presto!

If you're in the market for a weight loss supplement, there is no shortage of options. In 2020 alone, weight loss supplement makers in the United States made $33.4 billion and the numbers continue to rise. So how do you sort through all of the ads, the claims, the pills, and the powders to find a weight loss supplement that works? To make your research a bit easier, we've listed some of the most common weight loss supplements along with expert guidance about effectiveness and potential side effects.

What Are Weight Loss Supplements?

Weight loss supplements are tablets, pills, or powders that are consumed in addition to your regular diet. Companies that sell these products say that they can help you shed pounds faster and easier than diet and exercise alone. Sounds amazing, right? There are different ways that the products purport to make weight loss happen.

Types of Supplements

According to the National Institutes of Health (NIH), weight loss supplements claim to work in one of these three ways:

  • Appetite stoppers: These products claim they will help you feel less hungry so that you eat less and lose weight faster.
  • Fat blockers: This type claims to stop your body from absorbing fat - so you can eat as much bacon and ice cream as you want and it will go right through your system.
  • Fat burners: These say they work by helping you burn through your calories faster.

Supplements vs. Medications

Supplements are not medications. You can buy them without a doctor's prescription online or at your local pharmacy or grocery store. Supplements are also regulated differently than medications. While the U.S. Food and Drug Administration (FDA) requires pharmaceutical companies prove that medications are safe and effective before they can be sold, supplement companies do not have to provide this evidence. Instead, it is up to the supplement company itself to ensure that their products are safe.

Common Weight Loss Supplements

Supplement makers use many different ingredients to create their weight-loss products. A mix of minerals, vitamins, herbs, and sometimes fiber are blended and usually processed into powder or tablets. The NIH provides guidance to consumers about how different supplements work, about the potential side effects, and about how effective they are likely to be.

This comparison chart can help you to understand how each supplement might affect your weight loss journey. We chose to include a medication called orlistat in this list because it is available over the counter and some people might consider it when deciding to take a weight loss supplement.

Common Weight Loss Supplements Chart

Orlistat (alli)

Orlistat is a pharmaceutical drug that is sold under the brand name alli and regulated by the FDA as a medication. Orlistat works as a fat blocker and fat burner. According to the NIH, alli can help you lose weight in conjunction with diet and exercise. But side effects can include fatty stools, diarrhea, abdominal pain, and anal fissures.

Garcinia Cambogia

Garcinia cambogia is a fruit that is grown in warm climates. It contains hydroxycitric acid (HCA), a chemical that may have an effect on appetite. Garcinia cambogia supplements may act as an appetite regulator and may slow weight gain, but the NIH found it has little to no effect. It can also cause headaches, nausea, and digestive and respiratory symptoms.

Hydroxycut (Robusta Coffee Extract)

Hydroxycut is a combination supplement that works as a fat blocker. Its primary ingredient is robusta coffee extract (C. canephora robusta), but it also includes apple cider vinegar, plum, baobab extract, cardamom, and caffeine. According to the Hydroxycut website, it can help you lose weight. No reliable research has been done to measure how well Hydroxycut works, but many studies and case reviews have found that it may injure your liver if you take too much.


Glucomannan is a type of fiber. Supplements that contain this fiber often claim to absorb water in the gut to help you feel full, and thus work as an appetite blocker. The NIH reports it has little to no effect and can cause diarrhea, constipation, and excess gas.


Caffeine, commonly found in coffee, soda, and many types of tea, can help you to burn a few extra calories. So the NIH concluded that it may help you lose a little bit of weight or reduce weight gain slightly, but your body adjusts to it quickly, so its effect lessens over time. It can also cause shakiness and nervousness. At higher doses, you may experience nausea, vomiting, a fast heartbeat, or seizures.

Conjugated Linoleic Acid (CLA)

Conjugated linoleic acid is a type of fat found in some dairy and meat products. Supplements that contain CLA often claim to work as a fat burner. CLA may help you lose a "very small amount of weight" says the NIH, but it can also cause stomach upset, indigestion, constipation, and diarrhea.

Raspberry Ketones

Raspberry ketones are a chemical found in some types of fruit, including red raspberries. Raspberry ketone supplements often claim to act as a fat burner, but the NIH says its effects are largely unknown. More studies are needed to know what exactly this supplement does in the body.


Forskolin is a compound that comes from the root of a plant that grows in tropical climates. Supplements that contain it often claim to work as an appetite stopper and a fat burner. Studies through the NIH found it has no effect on weight loss, but that it can cause increased bowel movements and loose stools.

Green Tea

Green tea and green tea extract products often claim to work as a fat-burner, fat blocker, and some say it can cause your body to make less fat. The NIH says it can help you lose small amounts of weight, but can also cause constipation, abdominal discomfort, nausea, liver damage, and high blood pressure.

Green Coffee Bean Extract

Supplements that contain green coffee bean extracts often claim that they work by decreasing fat accumulation. The NIH reports it can help you lose small amounts of weight but that there are very few high quality studies supporting this benefit. The most commonly reported side effects include headaches and urinary tract infections.

Bitter Orange (Synephrine)

Makers of bitter orange supplements claim that it is an appetite stopper that also burns calories and fat. The NIH says that it may increase calories burned, but carries some substantial risks. After taking bitter orange, people have reported severe side effects including chest pain, anxiety, headaches, muscle and bone pain, and high heart rate and blood pressure.

Do Weight Loss Supplements Work?

The promises made by some weight loss supplement companies sound appealing. But the science supporting these claims is often inconsistent (in terms of methodology and results) and limited in scope. So while it may be tempting to take a pill for weight loss rather than using traditional methods such as diet and exercise, there are some good reasons to be skeptical.

One large-scale, peer-reviewed study provided insight into weight loss supplements as a whole. In 2021, the journal Obesity published a research report where study authors combed over 1,743 studies looking for study size, study quality, risk of bias, and (of course) results. Only 315 of these studies were high-quality trials. Of these, 16 studies showed weight loss after taking a dietary supplement. The amount lost ranged from under one pound to 11 pounds.

Study authors concluded that there is only weak evidence to support the use of supplements for weight loss. Furthermore, many health experts have concerns that some supplements may compromise your health. One 2013 study found 36 cases of severe liver damage in a group of people in Hawaii after taking a supplement called OxyELITE Pro. The product was taken off the market later that year.

Also, since supplements are not considered medications by the Food and Drug Administration (FDA) they do not oversee them the same way. This means that if you buy a bottle of weight-loss tablets with A, B, and C ingredients, one pill may have a ton of A and B, while another pill from the same bottle might have more C than anything else. If you don't know the ingredients in a pill you are taking, it can be hard to understand how it might interact with your health or with other medications or supplements you might be taking.

Should You Try a Weight Loss Supplement?

Only you and your healthcare provider can answer this question. Your health journey is your own. Speak with your provider and come up with a plan for your health. If part of your journey includes losing weight, you may want to try weight loss supplements.

Remember to double-check your supplement choice with your provider before you take it. Also, make sure to eat a healthy diet and add exercise to your routine alongside your supplement. Adjust your plan as needed, and try to enjoy the journey!

Do Weight Loss Supplements Really Work? Here's the Truth