According to the 2019 data, the U.S. weight loss market is worth a record $72 billion.

Those seeking weight loss embrace various approaches, from meal replacement and over-the-counter products and supplements to commercial diet chains and medically supervised programs. The big question is: do these weight loss supplements really work? If so, which ones are the best?

Acetyl-L-Carnitine (ALCAR)

Carnitine is an amino acid produced in the body and one of its main roles is to generate energy. Food sources of carnitine include animal proteins, particularly red meats. Carnitine is also available in supplement form as L-carnitine or Acetyl L carnitine (ALCAR).

Both L-carnitine and ALCAR show the ability to increase the fat-burning process, support muscle health, and enhance exercise performance, thus supporting weight loss. ALCAR may be a better choice than L carnitine because it crosses the blood-brain barrier, boosting brain function and reducing sugar cravings as well.

Grilled striploin steak karandaev / Getty Images



Omega-3 fatty acids are well known for their ability to improve blood lipid levels and heart and brain health. Researchers also evaluated their anti-obesity effects. In animal studies, omega-3s were found to promote weight loss. In human trials, there is less evidence for this.

However, research shows that they can be very helpful in the diet or as a supplement to maintain weight loss, offering benefits for some people who lose weight but have difficulty maintaining it long term.

Bottle of yellow fish oil pills on table Photo by Cathy Scola / Getty Images


Green Tea

Green tea extract is one of the most popular weight loss supplements. Older studies found that green tea and its active compounds — catechins like epigallocatechin-3-gallate (EGCG) and caffeine — support weight loss.

However, a 2012 review of multiple studies concluded that green tea preparations may only induce small, “statistically non-significant” weight loss in overweight or obese adults. Furthermore, green tea does not have significant benefits to maintain weight loss, though it does have some other health benefits.

Pouring green tea into a cup taa22 / Getty Images



Caffeine has been believed to promote weight loss for a long time. Coffee increases energy expenditure and fat oxidation. However, health experts believe that the extent to which these effects influence weight loss is not quite clear and more research is needed.

The American Medical Association recommends a limit of 500 mg/day caffeine. An 8-ounce cup of coffee contains roughly up to 100 mg caffeine. Guarana, Kola Nut, Yerba Maté, green tea, black tea also contain caffeine.

Cup of coffee and roasted coffee beans simarik / Getty Images



Capsaicin is a key active ingredient in chili peppers and is also responsible for their pungent flavor. Some studies suggest that this and other capsaicinoids may have anti-obesity effects because they increase energy expenditure, fat oxidation, and decrease appetite.

However, these products don't seem to cause significant weight loss, despite reducing the appetite, according to research.

Mix of chili peppers NatashaPhoto / Getty Images


Conjugated Linoleic Acid (CLA)

CLA is a mixture of natural molecules in beef dairy products. Research found that CLA promotes weight loss by increasing the breakdown of fats in the muscles and reducing the formation of fat from sugar molecules. A review of multiple studies concluded that a daily dose of 2.4–6 g/day of this supplement for 6 to 12 months helps reduce body fat by a mean of about 3 lbs, compared to the control group.

omega 6: conjugated linoleic acid (CLA) in capsules Bulgnn / Getty Images


Vitamin D

Vitamin D deficiency is common worldwide, and being overweight or obese further increases the risk of this deficiency. Some research found vitamin D supplements beneficial to losing weight, while others didn’t. Regardless of the effects on weight loss, health experts believe that correcting vitamin D deficiency is important for the heart, immune system, bones, and overall health.

Vitamin D supplements and food Jane Vershinin / Getty Images


Garcinia Cambogia

Garcinia cambogia is a tree native to Asia, Africa, and Polynesia. Its key active ingredient, hydroxycitric acid or HCA, is found in high amounts in the fruit, particularly in the pulp and rind. HCA may inhibit the conversion of sugars to fat, suppress appetite, and decrease weight gain.

However, this herbal supplement was associated with acute liver failure in some studies, and some individuals required a liver transplant.

Garcinia cambogia anoopkrishnan / Getty Images


Multi-Herbal Supplements

Many weight loss supplements contain numerous herbs combined, sometimes more than 10 ingredients. While the labels make the consumer think these supplements are better, this is often not true.

These multiple ingredients are often in tiny amounts, way below their therapeutic benefits. There is also a risk of interaction between the herbs, and many of the combinations have not been suitably researched.

Herbal medicine and herbs Elenathewise / Getty Images


Your Best “Weight Loss Supplement”

It is important to seek medical advice before using weight-loss supplements, to better understand their benefits, risks, and potential interactions with prescription medication.

Even so, the best weight loss "supplement" does not come in a bottle, but from making lifestyle changes. A healthy, balanced diet, regular exercise, a good night's sleep, and stress management are powerful tools to lose those extra pounds and maintain them long-term.

Nutritionist showing nutrition plan bymuratdeniz / Getty Images


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