| African mango (Irvingia gabonensis) |
Inhibits adipogenesis and reduces leptin levels |
Few clinical trials, all with small sample sizes
Research findings: Possible modest reduction in body weight and waist circumference |
No safety concerns reported for up to 3,150 mg/day for 10 weeks
Reported adverse effects: Headache, difficulty sleeping, flatulence, and gas |
| Beta-glucans |
Increase satiety and gastrointestinal transit time, and slow glucose absorption |
Several clinical trials with weight loss as a secondary outcome
Research findings: No effect on body weight |
No safety concerns reported for up to 10 g/day for 12 weeks
Reported adverse effects: Flatulence |
| Bitter orange (Citrus aurantium L.) |
Increases energy expenditure and lipolysis, acts as a mild appetite suppressant. Synephrine is the proposed active constituent. |
Small clinical trials of poor methodological quality
Research findings: Possible increase in resting metabolic rate and energy expenditure; inconclusive effects on weight loss |
Some safety concerns reported, especially for combinations with other stimulants
Reported adverse effects: Chest pain, anxiety, headache, musculoskeletal complaints, and increased blood pressure and heart rate |
| Caffeine (as added caffeine or from guarana, kola nut, yerba maté, or other herbs) |
Stimulates central nervous system, increases thermogenesis and fat oxidation |
Short-term clinical trials of combination products
Research findings: Possible modest effect on body weight or decreased weight gain over time |
Safety concerns not usually reported at intakes less than 400–500 mg/day for adults, significant safety concerns at higher doses
Reported adverse effects: Nervousness, jitteriness, vomiting, and tachycardia |
| Calcium |
Increases lipolysis and fat accumulation, decreases fat absorption |
Several large clinical trials
Research findings: No effect on body weight, weight loss, or prevention of weight gain based on clinical trials |
No safety concerns reported at recommended intakes (1,000–1,200 mg/day for adults)
Reported adverse effects: Constipation, kidney stones, and interference with zinc and iron absorption at intakes above 2,000–2,500 mg for adults |
| Capsaicin and other capsaicinoids |
Increase energy expenditure and lipid oxidation, increase satiety, and reduce energy intake |
Several clinical trials, mostly focused on energy intake and appetite
Research findings: Might reduce energy intake but no effect on body weight |
Few safety concerns reported for up to 33 mg/day for 4 weeks or 4 mg/day for 12 weeks
Reported adverse effects: Gastrointestinal distress, increased insulin levels, and decreased high-density lipoprotein (HDL) levels |
| Carnitine |
Increases fatty acid oxidation |
Several clinical trials with weight loss as a secondary outcome
Research findings: Possible modest reduction in body weight |
No safety concerns reported for up to 2 g/day for 1 year or 4 g/day for 56 days
Reported adverse effects: Nausea, vomiting, diarrhea, abdominal cramps, and a “fishy” body odor; might increase trimethylamine N-oxide (TMAO) levels, which are linked to greater cardiovascular disease risk |
| Chitosan |
Binds dietary fat in the digestive tract |
Small clinical trials, mostly of poor methodological quality
Research findings: Minimal effect on body weight |
Few safety concerns reported for 0.24–15 g/day for up to 6 months; could cause allergic reactions
Reported adverse effects: Flatulence, bloating, constipation, indigestion, nausea, and heartburn |
| Chromium |
Increases lean muscle mass; promotes fat loss; and reduces food intake, hunger levels, and fat cravings |
Several clinical trials of varying methodological quality
Research findings: Minimal effect on body weight and body fat |
No safety concerns reported for recommended intakes (20–45 mcg/day for adults)
Reported adverse effects: Headache, watery stools, constipation, weakness, vertigo, nausea, vomiting, and urticaria (hives) |
| Coleus forskohlii |
Enhances lipolysis and reduces appetite. Forskolin is the proposed active constituent. |
Few short-term clinical trials
Research findings: No effect on body weight |
No safety concerns reported at typical doses of 500 mg/day for 12 weeks
Reported adverse effects: More frequent bowel movements, loose stools |
| Conjugated linoleic acid (CLA) |
Increases lipolysis, reduces lipogenesis, and promotes apoptosis in adipose tissue |
Several clinical trials
Research findings: Minimal effect on body weight and body fat |
Few safety concerns reported for 2.4–6 g/day for up to 12 months
Reported adverse effects: Abdominal discomfort and pain, constipation, diarrhea, loose stools, dyspepsia, and (possibly) adverse effects on blood lipids and glucose homeostasis |
| Fucoxanthin |
Increases energy expenditure and fatty acid oxidation, suppresses adipocyte differentiation and lipid accumulation |
Studied only in combination with pomegranate-seed oil in one trial in humans
Research findings: Insufficient research to draw firm conclusions |
No safety concerns reported from one clinical trial that used 2.4 mg/day for 16 weeks, but not rigorously studied
Reported adverse effects: None known |
| Garcinia cambogia (hydroxycitric acid) |
Inhibits lipogenesis, suppresses food intake. Hydroxycitric acid is the proposed active constituent. |
Several short-term clinical trials of varying methodological quality
Research findings: Little to no effect on body weight |
Some safety concerns reported
Reported adverse effects: Headache, nausea, upper respiratory tract symptoms, gastrointestinal symptoms, mania, and liver damage |
| Glucomannan |
Increases feelings of satiety and fullness, prolongs gastric emptying time |
Several clinical trials of varying methodological quality, mostly focused on effects on lipid and blood glucose levels
Research findings: Little to no effect on body weight |
Significant safety concerns reported for tablet forms, which might cause esophageal obstructions, but few safety concerns with up to 15.1 g/day of other forms for several weeks
Reported adverse effects: Loose stools, flatulence, diarrhea, constipation, and abdominal discomfort |
| Green coffee bean extract (Coffea arabica, Coffea canephora, Coffea robusta) |
Inhibits fat accumulation, modulates glucose metabolism |
Few clinical trials, all of poor methodological quality
Research findings: Possible modest effect on body weight |
Few safety concerns reported for up to 200 mg/day for as long as 12 weeks, but not rigorously studied; contains caffeine
Reported adverse effects: Headache and urinary tract infections |
| Green tea (Camellia sinensis) and green tea extract |
Increases energy expenditure and fat oxidation, reduces lipogenesis and fat absorption |
Several clinical trials of good methodological quality on green tea catechins with and without caffeine
Research findings: Possible modest effect on body weight |
No safety concerns reported for use as a beverage, contains caffeine; some safety concerns reported for green tea extract
Reported adverse effects (for green tea extract): Constipation, abdominal discomfort, nausea, increased blood pressure, and liver damage |
| Guar gum |
Acts as bulking agent in gut, delays gastric emptying, increases feelings of satiety |
Several clinical trials of good methodological quality
Research findings: No effect on body weight |
Few safety concerns reported with currently available formulations containing up to 30 g/day for as long as 6 months
Reported adverse effects: Abdominal pain, flatulence, diarrhea, nausea, and cramps |
| Hoodia (Hoodia gordonii) |
Suppresses appetite, reduces food intake |
Very little published research in humans
Research findings: No effect on energy intake or body weight based on one study |
Some safety concerns reported, increases heart rate and blood pressure
Reported adverse effects: Headache, dizziness, nausea, and vomiting |
| Probiotics |
Alter gut microbiota, affecting nutrient and energy extraction from food and altering energy expenditure |
Several clinical trials
Research findings: Inconsistent effects on body fat, waist and hip circumference, and body weight |
No safety concerns reported for healthy individuals
Reported adverse effects: Gastrointestinal symptoms, such as gas |
| Pyruvate |
Increases lipolysis and energy expenditure |
Few clinical trials, all of weak methodological quality
Research findings: Possible minimal effect on body weight and body fat |
Few safety concerns reported for up to 30 g/day for as long as 6 weeks, but not well studied
Reported adverse effects: Diarrhea, gas, bloating, and (possibly) decreased HDL levels |
| Raspberry ketone |
Alters lipid metabolism |
Studied only in combination with other ingredients
Research findings: Insufficient research to draw firm conclusions |
No safety concerns reported in one 8-week study, but not well studied
Reported adverse effects: None known |
| Vitamin D |
None proposed; associations exist between low vitamin D status and obesity |
Several clinical trials
Research findings: No effect on body weight |
No safety concerns reported at recommended intakes (600–800 IU/day for adults); toxic at very high intakes; tolerable upper intake level of 4,000 IU/day for adults
Reported adverse effects: Anorexia, weight loss, polyuria, heart arrhythmias, and increased calcium levels leading to vascular and tissue calcification |
| White kidney bean (Phaseolus vulgaris) |
Interferes with breakdown and absorption of carbohydrates by acting as a “starch blocker” |
Several clinical trials of varying methodological quality
Research findings: Possible modest effect on body weight and body fat |
Few safety concerns reported for up to 3,000 mg/day for as long as 12 weeks
Reported adverse effects: Headache, soft stools, flatulence, and constipation |
| Yohimbe (Pausinystalia yohimbe) |
Has hyperadrenergic effects. Yohimbine is the proposed active constituent. |
Very little research on yohimbe for weight loss
Research findings: No effect on body weight; insufficient research to draw firm conclusions |
Significant safety concerns reported, especially for yohimbine doses of 20 mg or higher
Reported adverse effects: Headache, anxiety, agitation, hypertension, and tachycardia, myocardial infarction, cardiac failure, and death |
