You know the drill: you need to eat cleaner and move more if you want to lose weight.
That’s a given.
But what about that extra “boost”?
Enter: natural weight loss supplements.
The three most common ways diet aids work:
- Revving up the metabolism, so you burn more calories
- Decreasing nutrient absorption, especially fat, so total calorie intake drops
- Triggering appetite reduction that results in more feelings of satiation while eating less
The following are 15 of the most popular weight loss aids, along with the available evidence on how well they work:
Three separate studies found subjects taking green coffee bean extract lost an average of 5.4 pounds more than those who took the placebo. (3)
Added benefits include high levels of antioxidants, as well as the potential for lowering both blood sugar levels and blood pressure. (4, 5, 6, 7) Some of the potential side effects are nausea, diarrhea, insomnia and anxiety. (8)
Extracted from a plant in the mint family, forskolin raises cellular levels of a compound called cAMP, which is believed to cause increased fat burning. (9)
When 30 men overweight or obese men took forskolin, their weight didn’t change, but body composition did: they increased muscle mass and decreased fat mass. (10)
There’s no information on side effects or safety factors for forskolin.
A natural and harmless trans fat occurring in full-fat dairy products like butter and cheese, conjugated linoleic acid (CLA) is believed to cover all three bases: increase the body’s efficiency at breaking down fat, reduce the appetite, and kick up metabolic processes. (13, 14)
When 18 separate studies were reviewed, the average weight loss for subjects taking CLA amounted to 0.2 pounds weekly over a six-month period. (15)
A similar review conducted in 2012 reported participants lost an average of 3 pounds. (16)
CLA can cause digestive problems, and may contribute to the development of fatty liver disease, inflammation, and insulin resistance.
This pharmaceutical drug is designed to inhibit the breakdown of fat in the gut, leading to fewer calories absorbed from fatty foods eaten.
When data was correlated from 11 studies, subjects taking Alli lost up to 6 more pounds than those taking placebo pills. (17)
Digestive side effects can be intense, including flatulence and loose stools, as well as trouble controlling bowel movements.
The two plant extracts in Meratrim are supposed to cut back on the amount of fat snagged from the blood, assist in fat-burning processes, and make it more difficult for fat cells to multiply.
Since the product is relatively new, only one 8-week study has been done, but the results are promising. Meratrim users lost 11 pounds, and more than 4 inches of waist circumference, while following a 2000 calorie diet. (20)
The test group also dropped triglycerides, blood sugar and cholesterol with no side effects reported.
Several types of this weight loss supplement have been popular for more than a decade, with the most common one called simply “Hydroxycut.”
Plant extracts and caffeine in the product are credited with helping the trial group lose 21 pounds over three months. (21)
Anyone who is sensitive to caffeine is likely to experience irritability, nausea, diarrhea, and insomnia. No information on the long term effectiveness is available.
This substance imparts the distinctive smell to raspberries, and a synthetic version is reputed to help with weight loss.
Laboratory studies on fat cells taken from rats indicate the supplement can increase fat breakdown and jack up production of adiponectin, which researchers believe is linked to weight loss. (22)
No studies on the effectiveness of raspberry ketones have been done with human subjects.
This fiber comes from the roots of the elephant yam, and may help with weight loss through turning into a gel that lingers in the stomach, making you feel full. (23)
In three studies, the average weight loss over a 5-week period with subjects eating a healthy diet amounted to between 8 and 10 pounds. (24)
Glucomannan can also improve colon health through nourishing friendly bacteria in the gut (25), but may cause bloating and soft stools.
Included in many weight loss supplements, green tea extract contains EGCG, an antioxidant believed to help in burning fat. It may also increase norepinephrine, a fat-burning hormone. (26)
Supplements are usually tolerated well unless the user has a caffeine sensitivity, although levels are fairly low.
Found in coffee, dark chocolate and green tea, caffeine is a popular ingredient in supplements for weight loss because it boosts the metabolism by as much as 11% and causes up to 29% more fat to be burned. (29, 30, 31)
Studies show caffeine can contribute to weight loss, though the amounts are not dramatic. (32)
It’s important to keep in mind caffeine is addictive and can negatively impact quality of sleep. Some people experience other side effects as well, including diarrhea, nausea, anxiety and tremors.
The skin of this small, green fruit shaped like a pumpkin contains hydroxycitric acid, which is the active ingredient of diet pills sold as garcinia cambogia extract.
While animal studies indicate the substance inhibits enzymes that produce fat (33), a human study with 130 participants showed no difference in body weight between the group using the extract and the group taking a placebo. (34)
A review of 11 studies indicated average weight loss over several weeks for subjects taking garcinia cambogia extract was about 2 pounds. (35)
A few people reported mild digestive issues, but no serious side effects have been noted.
Extracted from the roots of the yacon plant, which is native to South America, yacon syrup contains fructooligosaccharides (FOS), which the body can’t digest. It imparts a sweet flavor with about a third of the calories you’d get in sugar.
While only one small study has been done with yacon syrup, the 40 women who used the supplement experienced excellent results.
The 15 women taking a placebo packed on about 3.5 pounds over four months, and the women using yacon syrup dropped 33 pounds. (38)
Since yacon syrup is a relative newcomer to the diet supplement scene, more research is likely to be done in the near future.
A bioactive compound originating in several types of plants, including the berberis shrub, berberine is an alkaloid that impacts the body at a molecular level.
It appears berberine can help drop blood sugar levels, lower cholesterol, and facilitate weight loss. Obese participants in a 12-week study lost an average of 5 pounds and 3.6% of body fat. (41)
In another study of the same duration, 37 obese men and women diagnosed with metabolic syndrome reduced body mass index (BMI) readings from 31.5 to 27.4 while improving other important health markers. (42)
Some digestive disturbances were reported, including stomach pain, diarrhea and flatulence.
Bitter Orange or Synephrine
This fruit contains a compound similar to ephedrine, which was commonly used in weight loss supplements in the past, most notably Ephedra, which was banned by the FDA due to serious side effects.
Synephrine is less potent than ephedrine, and can stimulate fat-burning activity as well as causing a reduction of appetite. (43)
Little study has been done with synephrine, but ephedrine proved effective for weight loss in the short term. (44)
Caution is advised, since it may be addictive and could have harmful effects on the heart.
Other pharmaceutical weight loss drugs
Among the most-prescribed medications for weight loss are Belviq, Qsymia, Contrave and Phentermine.
While these won’t make much difference unless used in combination with a sensible diet, studies show weight loss runs between 3% and 9% of body weight. (45)
Side effects vary with each drug.
Which Supplements are most effective?
Leaving out supplements with the most unpleasant or dangerous side effects, it appears that the best bet may be green tea extract.
Summary: Once you’ve made the decision to take off excess weight, boosting your metabolism and suppressing your appetite through weight loss supplements can help, but should only be a small part of your plan. Sticking to clean foods (avoid these) and a healthy lifestyle (see the best weight loss tips here) should be at the core of your weight loss.