What the research says about weight-loss supplements
Most weight-loss supplements combine a handful of familiar ingredients. Here is what independent research says about them, so you can judge any product's label for yourself.
The short answer
According to the U.S. National Institutes of Health's Office of Dietary Supplements (ODS), there is little scientific evidence that weight-loss supplements work, and the proven methods remain healthier eating, eating fewer calories and being more active. Some ingredients may help a small amount; many show little or no effect. Makers rarely run studies on their own products in people.
In the United States, supplement makers do not have to prove to the FDA that a product is safe or effective before selling it. That makes reading the label, and knowing what each ingredient can realistically do, important.
Common ingredients at a glance
| Ingredient | What it is claimed to do | What the evidence shows |
|---|---|---|
| Caffeine | Boost energy and fat burning | May help a little or reduce weight gain over time, but the body builds tolerance. Safe for most adults up to about 400–500 mg a day, but can cause jitters. |
| Green coffee bean extract | Reduce fat build-up | Might help with a small amount of weight loss. Also contains caffeine. |
| Green tea extract | Increase calorie burning | Effects appear small. Drinking green tea is safe, but concentrated extract pills have been linked to liver problems in some people. |
| Chromium | Reduce appetite and cravings | Might help with a very small amount of weight and fat loss. |
| Glucomannan | Fiber that helps you feel full | Little to no effect on weight, though it may help cholesterol and blood sugar. Can cause digestive discomfort. |
| Garcinia cambogia | Block fat and curb appetite | Little to no effect on weight loss. |
| Conjugated linoleic acid (CLA) | Reduce body fat | May help with a very small amount of weight and fat loss. |
| Bitter orange | Stimulant to burn calories | Unclear whether it helps. May not be safe: linked to raised heart rate and blood pressure. |
| Forskolin | Break down fat | So far, no clear effect on weight or appetite. Not well studied. |
Source: NIH Office of Dietary Supplements, Dietary Supplements for Weight Loss.
Why blends are hard to judge
Most products mix several ingredients, often in amounts that differ from the doses used in studies. Ingredients can also behave differently in combination. A product containing an ingredient that showed a small effect in one study does not mean the product itself has been shown to work.
Safety first
- Stimulant-heavy products can raise heart rate and blood pressure. Check total caffeine across everything you take.
- Supplements can interact with prescription and over-the-counter medicines.
- Speak to a doctor or pharmacist first if you are pregnant, breastfeeding, taking medication, or have heart, liver or blood pressure problems, or diabetes.