Supplements & Herbs
Vitamins that may be helpful
Multiple vitamin minerals
Diets that are low in total calories may not contain adequate amounts of various vitamins and minerals. For that reason, taking a multiple vitamin-mineral supplement is advocated by proponents of many types of weight-loss programs, and is essential when calorie intake will be less than 1,100 calories per day.61
Pyruvate, a compound that occurs naturally in the body, might aid weight-loss efforts.62 A controlled trial found that pyruvate supplements (22 to 44 grams per day) enhanced weight loss and resulted in a greater reduction of body fat in overweight adults consuming a low-fat diet.63 Three controlled trials combining 6 to 10 grams per day of pyruvate with an exercise program reported greater effects on weight loss and body fat than that seen with a placebo plus the exercise program.64, 65, 66 Animal studies suggest that pyruvate supplementation leads to weight loss by increasing theresting metabolic rate.67
5-HTP (5-hydroxytryptophan), the precursor to the chemical messenger (neurotransmitter) serotonin, has been shown in three short-term controlled trials to reduce appetite and to promote weight loss.68, 69, 70 In one of these trials (a 12-week double-blind trial), overweight women who took 600 to 900 mg of 5-HTP per day lost significantly more weight than did women who received a placebo.71 In a double-blind trial with no dietary restrictions, obese people with type 2(non-insulin-dependent) diabetes who took 750 mg per dayof 5-HTP for two weeks significantly reduced their carbohydrate and fat intake. Average weight loss in two weeks was 4.6 pounds, compared with 0.2 pounds in the placebo group.72
The ability of 7-KETO (3-acetyl-7-oxo-dehydroepiandrosterone), a substance related to DHEA, to promote weight loss in overweight people has been investigated in one double-blind trial.73 Participants in the trial were advised to exercise three times per week for 45 minutes and to eat an 1,800-calorie-per-day diet. Each person was given either a placebo or 100 mg of 7-KETO twice daily. After eight weeks, those receiving 7-KETO had lost more weight and lowered their percentage of body fat further compared to those taking a placebo. These results may have been due to increases in levels of a thyroid hormone (T3) that plays a major role in determining a person's metabolic rate, although the levels of T3 did not exceed the normal range.
Biochemical and animal research show that HMB has a role in protein synthesis and might, therefore, improve muscle growth and overall body composition when given as a supplement. However, double-blind human research suggests that HMB may only be effective when combined with an exercise program in people who are not already highly trained athletes. Double-blind trials found no effect of 3 to 6 grams per day of HMB on body weight, body fat, or overall body composition in weight-training football players or other trained athletes.74, 75, 76, 77, 78 However, one double-blind study found that 3 grams per day of HMB increased the amount of body fat lost by 70-year old adults who were participating in a strength-training program for the first time.79 A double-blind study of young men with no strength-training experience reported greater improvements in muscle mass (but not in percentage body fat) when HMB was used in the amount of 17 mg per pound of body weight per day.80 However, another group of men in the same study given twice as much HMB did not experience any changes in body composition.
In a study of obese people consuming a low-calorie diet for 24weeks, those receiving a calcium supplement (800 mg per day) lost significantlymore weight than those given a placebo.81 Calcium waseffective when provided either as a supplement, or in the form of dairyproducts. In a second study, however, the amount of weight loss resultingfrom calcium supplementation (1,000 mg per day) was small and not statisticallysignificant.82 In that study, participants' typical diet containedmore calcium than in the study in which calcium supplementation was moreeffective. Thus, it is possible that calcium supplementation enhances weightloss only when the diet is low in calcium.
A double-blind trial found that exercising individuals taking 1,800 mg per day of conjugated linoleic acid (CLA) lost more body fat after 12 weeks than did a similar group taking a placebo.83 However, two other studies found that amounts of CLA from 0.7 to 3.0 grams per day did not affect body composition.84, 85 Most double-blind trials have found that larger amounts of CLA, 3.2 to 4.2 grams per day, do reduce body fat;86, 87, 88, 89 however, one double-blind study of experienced strength-training athletes reported no effect of 6 grams per day of CLA on body fat, muscle mass, or strength improvement.90
Fiber supplements are one way to add fiber to a weight-loss diet. Several trials have shown that supplementation with fiber from a variety of sources accelerated weight loss in people who were following a low-calorie diet.91, 92, 93, 94 Other researchers found, however, that fiber supplements had no effect on body weight, even though it resulted in a reduction in food intake.95
Supplementation with 3 to 4 grams per day of a bulking agent called glucomannan, with or without a low-calorie diet, has promoted weight loss in overweight adults,96, 97, 98 while 2 to 3 grams per day was effective in a group of obese adolescents in another controlled trial.99
(-)-Hydroxycitric acid (HCA), extracted from the rind of the Garcinia cambogia fruit grown in Southeast Asia, has a chemicalcomposition similar to that of citric acid (the primary acid in oranges and other citrus fruits). Preliminary studies in animals suggest that HCA may be a useful weight-loss aid.100, 101 HCA has been demonstrated in the laboratory (but not yet in clinical trials with people) to reduce the conversion of carbohydrates into stored fat by inhibiting certain enzyme processes.102, 103 Animal research indicates that HCA suppresses appetite and induces weight loss.104, 105, 106, 107 However, a double-blind trial found that people who took 1,500 mg per day of HCA while eating a low-calorie diet for 12 weeks lost no more weight than those taking a placebo.108 A double-blind trial of Garcinia cambogia (2.4 grams of dry extract, containing 50% hydroxycitric acid) found that the extract did not increase energy expenditure; it was therefore concluded that this extract showed little potential for the treatment of obesity at this amount.109 Nonetheless, another double-blind trial found that using the same amount of Garciniacambogia extract significantly improved the results of a weight-loss diet, even though the amount of food intake was not affected.110
Amylase inhibitors are also known as starch blockers because they contain substances that prevent dietary starches from being absorbed by the body. Starches are complex carbohydrates that cannot be absorbed unless they are first broken down by the digestive enzyme amylase and other, secondary, enzymes.111, 112 When starch blockers were first developed years ago, they were found not to be potent enough to prevent the absorption of a significant amount of carbohydrate.113, 114, 115, 116 Recently, highly concentrated starch blockers have been shown to be more effective,117, 118, 119 but no published human studies exist investigating their usefulness for weight loss.
Blue-green algae, or spirulina, is a rich source of protein, vitamins, minerals, and essential fatty acids. In one double-blind trial, overweight people who took 2.8 grams of spirulina three times per day for four weeks experienced only small and statistically nonsignificant weight loss.120 Thus, although spirulina has been promoted as a weight-loss aid, the scientific evidence supporting its use for this purpose is weak.
Chitosan is a fiber-like substance extracted from the shells of crustaceans such as shrimp and crab. Animal studies suggested that chitosan supplementation reduces fat absorption, but controlled human trials have found no impairment of fat absorption from supplementation with 2,700 mg of chitosan per day for seven days or 5,250 mg per day for four days.121, 122 A double-blind study found that people taking 1,500 mg of chitosan three times per day during a weight-loss program lost significantly more weight than did people taking a placebo with the same program.123 Similar benefits were seen in another double-blind study that used 3,000 mg of chitosan per day.124 Other studies using smaller amounts of chitosan have reported no effects on weight loss.125, 126, 127
The mineral chromium plays an essential role in the metabolism of carbohydrates and fats and in the action of insulin. Chromium, usually in a form called chromium picolinate, has been studied for its potential role in altering body composition. Chromium has primarily been studied in body builders, with conflicting results.128 In people trying to lose weight, a double-blind study found that 600 mcg per day of niacin-bound chromium helped some participants lose more fat and less muscle.129 However, three other double-blind trials have found no effect of chromium picolinate on weight loss,130, 131, 132 though in one of these trials lean body mass that was lost during a weight-loss diet was restored by continuing to supplement chromium after the diet. A recent comprehensive review combining the results of ten published and unpublished double-blind studies concluded that chromium picolinate supplementation may have a small beneficial effect on weight loss.133
One double-blind trial found 100 mg per day of DHEA was effective for decreasing body fat in older men,134 and another double-blind trial found 1,600 mg per day decreased body fat and increased muscle mass in younger men,135. However, DHEA has not been effective for improving body composition in women or in other studies of men.136, 137, 138, 139, 140, 141, 142, 143
Guar gum, another type of fiber supplement, has not been effective in controlled studies for weight loss or weight maintenance.144, 145, 146
The amino acid L-carnitine is thought to be potentially helpful for weight loss because of its role in fat metabolism. In a preliminary study of overweight adolescents participating in a diet and exercise program, those who took 1,000mg of L-carnitine per day for three months lost significantly more weight than those who took a placebo.147 A weakness of this trial, however, was the fact that the average starting body weight differed considerably between the two groups. A double-blind trial found that adding 4,000 mg of L-carnitine per day to an exercise program did not result in weight loss in overweight women.148
Sesamin is substance present in sesame oil that manufacturers claim may enhance fat burning by increasing the activity of several liver enzymes that break down fatty acids. It is believed that optimizing the liver's fat-burning capacity may promote fat loss; however, Healthnotes has not seen published research to support the claims.
Animal and human studies have suggested that when soy is used as a source of dietary protein, it may have several biological effects on the body that might help with weight loss.149 A preliminary study found that people trying to lose weight using a meal-replacement formula containing soy protein lost more weight than a group not using any formula.150 However, controlled studies comparing soy protein with other protein sources in weight-loss diets have not found any advantage of soy.151, 152, 153 When soy protein is used for other health benefits, typical daily intake is 20 grams per day or more.
Whey protein may aid weight loss due to its effect on appetite. In a preliminary study, people were given 48 grams of either whey protein or milk protein (casein). Whey consumption resulted in more hunger satisfaction and reduced the amount of food eaten 90 minutes later compared with casein consumption.154 However, a double-blind study found that men taking 1.5 grams per 2.2 lbs body weight per day of whey protein for 12 weeks along with a low-calorie diet and a strength training exercise program lost the same amount of weight and body fat as did a control group that followed a similar program, but took a casein supplement instead of whey protein.155
Herbs that may be helpful
Research has suggested that incorporating cayenne pepper into the diet may help people lose weight. Controlled studies report that adding 6 to 10 grams of cayenne to a meal or 28 grams to an entire day's diet reduces hunger after meals and reduces calories consumed during subsequent meals.156, 157 Other controlled studies have reported that calorie burning by the body increases slightly when 10 grams of cayenne is added to a meal or 28 grams is added to an entire day's diet 158, 159, 160 However, no studies have been done to see if regularly adding cayenne to the diet has any effect on weight loss.
Green tea extract rich in polyphenols (epigallocatechin gallate, or EGCG) may support a weight-loss program by increasing energy expenditure or by inhibiting the digestion of fat in the intestine.161, 162 Healthy young men who took two green tea capsules (containing a total of 50 mg of caffeine and 90 mg of EGCG) three times a day had a significantly greater energy expenditure and fat oxidation than those who took caffeine alone or placebo.163 In a preliminary study of moderately obese individuals, administration of a specific green tea extract (AR25) resulted in a 4.6% reduction in average body weight after 12 weeks.164 The amount of green tea extract used in this study supplied daily 270 mg of EGCG and 150 mg of caffeine. While caffeine is known to stimulate metabolism, it appears that other substances besides caffeine were responsible for at least part of the weight loss. Although the extract produced few side effects, one individual developed abnormal liver function tests during the study. In another study, consuming approximately 12 ounces of oolong tea (a semifermented version of green tea) daily for 12 weeks reduced waist circumference and the amount of body fat in a group of normal-weight to overweight men.165 Additional studies are needed to confirm the safety and effectiveness of green tea extracts for promoting weight loss.
One small, double-blind clinical study in humans found that hoodia latex and inner plant can significantly reduce food intake. Available products are of unknown quality and much more work remains to be done to determine if hoodia will be a sustainable, safe way to reduce appetite.166
The ability of yohimbine, a chemical found in yohimbe bark, to stimulate the nervous system, 167, 168 and to promote the release of fat from fat cells,169, 170 has led to claims that it might help weight loss by raising metabolic rate, reducing appetite, or increase fat burning. Although a preliminary trial found yohimbine ineffective for weight loss, a double-blind study found that women taking 5 mg of yohimbine four times per day along with a weight-loss diet lost significantly more weight than those taking a placebo with the same diet after three weeks.171 However, a similar study using 18 mg per day of yohimbine for eight weeks reported no benefit to weight loss compared with a placebo.172 A double-blind study of men who were not dieting reported no effect of up to 43 mg per day of yohimbine on weight or body composition after six months.173 All of these studies used pure yohimbine; no study has tested the effects of yohimbe herb on weight loss.
Although historically used to stimulate appetite, bitter orange is frequently found in modern weight-loss formulas because synephrine is similar to the compound ephedrine, which is known to promote weight loss. In one study of 23 overweight adults, participants taking a daily intake of bitter orange (975 mg) combined with caffeine (525 mg) and St. John's wort (Hypericum perforatum, 900 mg) for six weeks lost significantly more body weight and fat than the control group.174 No adverse effects on heart rate or blood pressure were found. Bitter orange standardized to contain 4 to 6% synephrine had an anti-obesity effect in rats. However, the amount used to achieve this effect was accompanied by cardiovascular toxicity and mortality.175
Although no clinical trials have been done, there are modern references to use of the herb coleus for weight loss.176 Coleus extracts standardized to 18% forskolin are available, and 50 to 100 mg can be taken two to three times per day. Fluid extract can be taken in the amount of 2 to 4 ml three times per day.
The herb guaraná contains caffeine and the closely related alkaloids theobromine and theophylline; these compounds may curb appetite and increase weight loss. Caffeine's effects are well known and include central nervous system stimulation, increased metabolic rate, and a mild diuretic effect.177 In a double-blind trial, 200 mg per day of caffeine was, however, no more effective than a placebo in promoting weight loss.178 Because of concerns about potential adverse effects, many doctors do not advocate using caffeine or caffeine-like substances to reduce weight.
Coupled with exercise in a double-blind trial, a combination of guggul, phosphate salts, hydroxycitrate, and tyrosine has been shown to improve mood with a slight tendency to improve weight loss in overweight adults.179 Daily recommendations for guggul are typically based on the amount of guggulsterones in the extract. A common intake of guggulsterones is 25 mg three times per day. Most guggul extracts contain 5 to 10% guggulsterones and can be taken daily for 12 to 24 weeks.
Manufacturers of relora, a product derived from Magnolia officinalis and Phellodendron amurense bark, claim that the extract helps balance hormones such as cortisol, which are associated with weight gain. Healthnotes has not seen published research demonstrating that relora promotes weight loss.