There are plenty different weight loss solutions in the market (e.g. pills, drugs, and natural supplements among others). They tend to work via one or more of these mechanisms:
- Reduce appetite, making you feel more full so that you eat fewer calories.
- Reduce absorption of nutrients like fat, making you take in fewer calories.
- Increase fat burning, making you burn more calories.
Here are the 12 most popular weight loss pills and supplements, reviewed by science.
1. Garcinia Cambogia Extract
Garcinia cambogia1 is a small, green fruit, shaped like a pumpkin. It contains hydroxycitric acid (HCA). It is the active ingredient in garcinia cambogia extract – a diet pill.
Hydroxycut2 is one of the most popular weight loss solution in the market. There are several types of hydroxycut, but the most common one is simply called “Hydroxycut.”
How it works: It contains several ingredients that are claimed to help with weight loss, including caffeine and a few plant extracts.
Effectiveness: A study showed that it caused 21 lbs (9.5 kg) of weight loss over a 3 month period.
Caffeine is the most commonly consumed psychoactive substance and is naturally found in coffee, green tea, and dark chocolate. It is a metabolism booster.
4. Orlistat (Alli)
Orlistat is a pharmaceutical drug, sold over-the-counter under the name Alli, and under prescription as Xenical.
How it works: It works by inhibiting the breakdown of fat in the gut to make you take fewer calories.
Effectiveness: According to a review of 11 studies, orlistat can increase weight loss by 6 pounds (2.7 kg) compared to a dummy pill.
5. Raspberry Ketones
Raspberry ketone is a substance found in raspberries. A synthetic version of raspberry ketones is sold as a weight loss supplement.
How it works: According to studies conducted in animals, raspberry ketones increase breakdown of fat and increase levels of a hormone called adiponectin, believed to be related to weight loss.
Effectiveness: There is not a single study on raspberry ketones in humans. However, a rat study using massive doses showed that they reduced weight gain.
6. Green Coffee Bean Extract
Green coffee beans are normal coffee beans that haven’t been roasted. They contain two substances believed to help with weight loss, caffeine and chlorogenic acid3.
How it works: Caffeine can increase fat burning, and chlorogenic acid slows the breakdown of carbohydrates in the gut.
Effectiveness: Several human studies have shown that green coffee bean extract can help people lose weight. Furthermore, a review of 3 studies found that the supplement made people lose 5.4 more pounds (2.5 kg) than placebo, a dummy pill.
Glucomannan4 is a type of fiber found in the roots of konjac5.
How it works: Glucomannan absorbs water and becomes gel-like. It “sits” in your gut and promotes a feeling of fullness, helping you eat fewer calories.
Effectiveness: Three human studies showed that glucomannan, combined with a healthy diet, can help people lose 8-10 pounds (3.6-4.5 kg) of weight in 5 weeks.
Meratrim6 is a combination of two plant extracts that may change the metabolism of fat cells.
How it works: Meratrim makes it harder for fat cells to multiply, and decrease the amount of fat that they pick up from the bloodstream, and help them burn stored fat.
Effectiveness: Only one study has been done on Meratrim so far. A total of 100 obese people were placed on a strict 2000 calorie diet, with either Meratrim or a dummy pill.
After 8 weeks, the Meratrim group had lost 11 pounds (5.2 kg) of weight and 4.7 inches (11.9 cm) off their waistlines. They also had improved quality of life and reduced blood sugar, cholesterol and triglycerides.
9. Green Tea Extract
How it works: Green tea extract is believed to increase the activity of norepinephrine, a hormone that helps you burn fat.
10. Conjugated Linoleic Acid (CLA)
Conjugated linoleic acid7, or CLA, is one of the “healthier” trans fats, and is found naturally in some fatty animal foods like cheese and butter.
Effectiveness: A review of 18 different studies shows that CLA caused weight loss of about 0.2 pounds (0.1 kg) per week, for up to 6 months. Moreover, in another review study from 2012, CLA was shown to have caused a loss of 3 lbs (1.3 kg) of weight compares to a dummy pill.
According to another review study from 2012, CLA can make you lose about 3 lbs (1.3 kg) of weight, compared to a dummy pill.
Forskolin8 is an extract from a plant in the mint family, claimed to be effective for losing weight.
How it works: It is believed to raise levels of a compound inside cells called cAMP, which may stimulate fat burning.
Effectiveness: A study conducted in 30 overweight and obese men showed that forskolin reduced body fat and increased muscle mass, while having no effect on body weight. Another study in 23 overweight women found no effects.
12. Synephrine or “Bitter Orange”
Bitter orange is a type of orange that contains the compound synephrine. Synephrine9 is related to ephedrine, which used to be a popular ingredient in various weight loss pill formulations. Ephedrine10, however, has since been banned as a weight loss ingredient due to its adverse side effects.
How it works: Synephrine shares similar mechanisms with ephedrine, but is less potent. It can reduce appetite and significantly increase fat burning.
Effectiveness: Very few studies have been done on synephrine, but ephedrine has been shown to cause significant short-term weight loss in many studies.
A Word to the Wise
Out of the 12, the following are widely supported by scientific ecidence:
- Weight loss: Glucomannan, CLA and Orlistat (Alli); and
- Increased fat burning: Caffeine and green tea extract.
They may give your metabolism a bit of a nudge and help you lose a few pounds, but that’s where it ends, unfortunately. Cutting carbs and eating more protein are still the best ways to lose weight, and work better than all the diet pills combined.
1“Garcinia Cambogia: Safe for Weight Loss? – WebMD.” 2014. 13 Mar. 2016 <http://www.webmd.com/vitamins-and-supplements/garcinia-cambogia-weight-loss>
2“Hydroxycut | Weight Loss Supplements | Lose Weight Your …” 2002. 13 Mar. 2016 <http://www.hydroxycut.com/>
3“Chlorogenic Acid – Scientific Review on Usage, Dosage …” 2015. 13 Mar. 2016 <https://examine.com/supplements/chlorogenic-acid/>
4“GLUCOMANNAN: Uses, Side Effects, Interactions and …” 2012. 13 Mar. 2016 <http://www.webmd.com/vitamins-supplements/ingredientmono-205-glucomannan.aspx?activeingredientid=205&activeingredientname=glucomannan>
6“VITAL Facts About Meratrim: Reviews, Ingredients and …” 2014. 13 Mar. 2016 <http://skinnywithfiber.org/vital-facts-about-meratrim-reviews-ingredients-and-possible-side-effects/>
7“CONJUGATED LINOLEIC ACID: Uses, Side Effects …” 2014. 13 Mar. 2016 <http://www.webmd.com/vitamins-supplements/ingredientmono-826-conjugated%20linoleic%20acid.aspx?activeingredientid=826&>
8“COLEUS: Uses, Side Effects, Interactions and Warnings …” 2016. 13 Mar. 2016 <http://www.webmd.com/vitamins-supplements/ingredientmono-1044-coleus.aspx?activeingredientid=1044&>
9“Synephrine – Scientific Review on Usage, Dosage, Side …” 2015. 13 Mar. 2016 <https://examine.com/supplements/synephrine/>
10“Ephedrine: Uses, Dosage & Side Effects – Drugs.com.” 2008. 13 Mar. 2016 <http://www.drugs.com/ephedrine.html>