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OTC medications and supplements

Last updated October 25, 2007. The Obesity-news over-the-counter (OTC) medications and supplements FAQ gives a brief description of each OTC compound that has been tested in clinical weight loss trials and provides hyperlinks to relevant articles on the Obesity-news site. None of the medications or supplements reviewed below is FDA approved for weight loss. The only over-the-counter FDA approved weight loss medication, phenylpropanolamine, was withdrawn from the US market in November 2000. Ephedra supplements were removed from the US market by the FDA in 2004, but ephedrine is still available in drug stores. Ephedra and ephedrine products are not FDA approved for weight loss.

OTC supplements and weight loss

There are many medications and supplements available over-the-counter (OTC) which have been shown to be safe and effective for weight loss in clinical studies. However, this does not mean that the products being sold in your local health food store or vitamin shop will help you lose weight.

Clinical studies use pharmaceutical grade compounds, many times in higher doses, in different combinations, or manufactured in a different manner than commercially available products.

It is important to get your information about over-the-counter products from reliable sources. Never accept the word of a company that sells weight loss products. Read the studies yourself, or summaries from publications which have no affiliations with supplement companies and do not sell weight loss products. Study summaries in credible newsletters will also contain the citation(s) of the article(s) reviewed.

When deciding whether or not to take a supplement, you should consider a number of factors:

  • Do any clinical studies support the use of this product for weight loss?
    If a product has been shown to produce weight loss, you will find the results of positive clinical trials on it in medical journals and reviews of those studies in reliable magazines and newsletters. The National Institutes of Health maintains a medline database of most journals in Pub Med, where you can get the citation, abstract, and occasionally the full-text journal article of such studies. For example, if you do a medline for the popular supplement calorad, you will find that no research has been conducted on it.

  • Were the studies conducted on human subjects?
    A favorite ploy of supplement hucksters is to reference animal studies as proof that their product will help you lose weight. If no studies have been conducted on human subjects, there is no proof that it works. Rodents are good, but not perfect models for people, and often compounds that work well on rodents are not effective on humans or they produce adverse reactions. This is part of the reason why few compounds advance from preclinical research to FDA approval in the drug development process.

  • Does the product contain the same ingredients and dose as used in studies?
    Increasingly supplement companies are developing products containing dozens of ingredients. In general, these types of supplements contain lower doses and combinations of ingredients which have never been tested on people. Companies producing "fat burners" are particularly guilty of putting everything but the kitchen sink into weight loss products. Adding additional ingredients, even ingredients that have tested well in separate studies, is no guarantee that you'll have better weight loss results with one of these products. The results could be worse, or you could get an adverse reaction. When buying supplements it is very important to check the label to make sure that the dosage and ingredients are correct. In addition, the manufacturing process of the supplement may be important.

  • What effect will the product have on me over the long term?
    Most studies on supplements and compounds were conducted over relatively short periods of time, so safety and or efficacy may not be assured over the long term. Make sure you know the details of the studies, including dose, length of study, and possible side effects of the compound(s) tested.

  • Will the product interact with a medication I am already taking, or cause an adverse reaction?
    If you are taking medication or have a health condition which may interfere with your taking OTC products, speak with your doctor first. Know the possible side effects of supplements before you take them so you can determine if they are right for you. Patients using supplements on a chronic basis should inform their health care provider. OTC products can interact with prescription medications and cause conditions like high blood pressure.

Be an informed consumer, which means reading the studies or reliable summaries on the products you use and buying products from reliable, well-known companies. Do not buy a product if you cannot determine that the proper ingredients are present in the proper dosage. As a rule, stay away from multi-level-marketing (MLM) supplement companies, or those that produce just a single product.


Tryptophan is an essential amino acid and a precursor to the brain neurotransmitter serotonin. In 1989 over-the-counter sales of tryptophan were banned in the US after a contaminated batch caused an outbreak of eosinophilia-myalgia syndrome in around 1,500 individuals. However, a metabolite of tryptophan, 5-hydroxy tryptophan (5-HTP), has been found to be just as effective and is available in most health food stores and vitamin shops.

Several short-term studies have been conducted on 5-HTP, carbohydrate cravings and appetite. In the studies, subjects given 5-HTP reduced their food intake, carbohydrate consumption, and lost weight. But the dosage used in these studies was substantially higher than what is contained in commercial preparations.

Obesity-news has covered the studies that look at the role of tryptophan and 5-HTP in weight loss. See the following articles and resources from our site:


Calcium/vitamin D

Several studies indicate that dieting patients who get adequate calcium and vitamin D lose more weight than those who do not. Research has found that calcium and vitamin D play an important role in lipid metabolism and triglyceride storage. When the body has too little calcium and vitamin D, it is sequestered in fat cells. This condition results in weight gain and eventually metabolic diseases like high blood pressure, diabetes and high cholesterol.

Calcium stored in fat cells (intracellular calcium) causes the metabolic derangements associated with obesity by stimulating receptors or voltage mediated calcium channels and activating an enzyme involved in fat storage known as fatty acid synthase (FAS). This process results in triglyceride accumulation, increased fat storage (lipogenesis) and decreased fat metabolism (lipolysis). When the body receives adequate calcium, either through the diet or supplementation, the storage of calcium in adipocytes is suppressed and weight loss occurs. Animal studies indicate that this may occur through activation of UCP2 and an increase in thermogenesis.

Our publicly available review article from the June 2000 issue will give you more details on the studies.



Cimetidine, an H-2 histamine blocker sold over-the-counter as Tagamet, is used to treat gastric acid and peptic ulcers. It is not currently FDA approved for weight loss. Several studies have reported that cimetidine reduces weight in healthy overweight subjects. Although the method of action is not completely understood, a prevailing theory is that the satiety peptide cholecystokinin plays a role in cimetidine induced appetite suppression.

The last known studies on cimetidine for weight loss were published in the year 2000. Obesity-news reviews of the literature are listed below:


Conjugated linoleic acid

Conjugated linoleic acid (CLA) is a type of fat found in milk and meat products that has a potent effect on body weight in rodents and protects against the loss of lean body mass caused by dieting. However, the effects found in laboratory animals have not been replicated in human subjects. In humans CLA has been shown to reduce fat mass and increase lean body mass, but does not have much effect on overall body weight nor on plasma lipids.

Obesity-news wrote an extensive review article on CLA and bodyweight in September 2001 (listed below). A more recent review of the literature is available to the public in the March 2004 issue of the American Journal of Clinical Nutrition. Later studies have not made any new findings on CLA and weight loss, but more recent animal data indicate that CLA may be associated with insulin resistance.



Ephedrine is an over-the-counter stimulant used to treat asthma, and is used "off-label" alone or in combination with caffeine and/or aspirin for weight loss. More than 100 weight loss studies have been conducted on ephedrine, ephedrine/caffeine, and ephedrine/caffeine/aspirin (ECA stack), most of which have had positive results. More recently, several herbal ephedra products have been tested in controlled clinical trials and were shown to be effective.

Ephedrine increases fat burning functions and limits fat storage by stimulating the sympathetic nervous system and elevating circulating catecholamine levels. Catecholamines in turn stimulate beta-1 (-1), beta-2 (-2), and at high levels beta-3 (-3) receptors in adipocytes (fat cells). This results in increased lipolysis and decreased lipogenesis (fat storage) in fat cells and increased thermogenesis in brown adipose tissue and skeletal muscle.

Caffeine and aspirin are often combined with ephedrine to inhibit "negative feedback" or drug tolerance which can occur when stimulants are taken on a long-term basis. Human studies up to 26 weeks seem to show that caffeine has an additive effect, but there are few studies showing that aspirin increases the effectiveness of ephedrine.

2005 update. A number of ephedra supplements were on the market until February 2004, when the Food And Drug Administration (FDA) removed them citing health risks. However, it is still possible to make EC or ECA stacks using the over-the-counter drug ephedrine.

Obesity-news has covered the subject of ephedrine and weight loss extensively, and our site contains a host of review articles, study summaries and resource pages:



Hoodia is a South African succulent that has been eaten by the South African San Bushmen for thousands of years to stave off thirst and hunger during long hunting trips. After the pharmaceutical company Phytopharm became interested in this plant for the treatment of obesity, hoodia began appearing in a number of diet products. In a phase IIa clinical trial, Phytopharm's hoodia extract, named P57, reduced feeding in obese volunteers by 1,000 calories per day by the end of two weeks, and significantly decreased body fat.

Who owns the rights to hoodia? Phytopharm licensed the P57 patent from South Africa's Council for Scientific and Industrial Research (CSIR) in 1997, and partnered with Pfizer to fund development of a botanical based pharmaceutical appetite suppressant from the compound. However, Pfizer pulled out of the agreement in 2003 leaving Phytopharm without funds for further development. With the future of the program in question, Phytopharm changed tactics and took steps to develop P57 as a diet food additive. By the end of 2004, the company signed a new agreement with Unilever, the manufacturer of Slim-Fast, for inclusion of hoodia in diet foods. The CSIR position is that it and Phytopharm own the rights to the active ingredient and to market hoodia as an appetite suppressant. All other products infringe on the patent. Hoodia supplement manufacturers take the position that while others might own the patent to the active ingredient, the plant itself cannot be patented.

Supply. Regardless of the legality of either position, obtaining South African Hoodia is difficult. There is a limited supply available through "licensed South African farmers", but a drought and the recent inclusion of hoodia in the Annex II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in October 2004, has made it much harder, and more expensive to obtain. Hoodia from other countries, like China and Israel, has not been proven to be effective.

How much hoodia is enough? That's hard to say. In the first place, being that hoodia is a plant, the actual active ingredient can vary from crop to crop. This means a dose 400 mg of powdered hoodia from one crop may not have the same potency as 400 mg from another crop. Extraction processes, other than Phytopharm's, have proven unreliable, and many products using 20:1 extracts have been shown to have little active ingredient in them when subjected to laboratory analysis. No supplement company can tell you exactly how much is enough, but most recommend doses above 2,400 mg (2.4 g) per day; individual capsule size ranges from 400 mg to 750 mg. Many web-based supplement companies are publishing their certificate of analysis which shows the country of origin and potency of the source material. Some even show farming licenses and individual CITES export certificates indicating that the product has been legally obtained and exported. However, hoodia supplement companies are largely unknown, upstart entities, leaving the question as to whether the material in the bottle is the same what is on the certificate.

What to buy. Buy products that contain capsules of 100 percent hoodia in dosages of 400 mg or above. Certificates are a plus. Buying from a US based company is also a plus; it can take a month or more to get your product directly from South Africa. If the company makes it difficult to determine what's in the bottle or the product contains "everything-but-the-kitchen-sink" stay away.

Over the past 5 years, Obesity-news has covered the development of P57 extensively. Our most recent monograph, from February 2005, contains a more complete analysis on the development of P57 as a dietary food product. Below is a list of our P57 coverage:



The effect of tea on body weight is generally attributed to its caffeine content. But more recent studies indicate that a class of antioxidant polyphenols, known as catechins, may act synergistically with caffeine to cause increased energy expenditure in both obese and lean individuals. Other studies have suggested possible action on pancreatic lipase. Numerous experiments have shown positive effects of tea and tea supplements on energy expenditure, thermogenesis and body weight, although data from carefully controlled studies are lacking.

There are 3 categories of tea -- black, green, and oolong, with black tea accounting for 80 percent of total tea intake world wide. Black tea leaves are fermented and contain mostly theaflavins and thearubigins, catchetin polymers formed during the fermentation process. Green tea is a nonoxidized, nonfermented tea, which contains polyphenol compounds like epicatechin, epicatechin gallate, epigallocatechin, and epigallocatechin gallate (EGCG). Oolong tea is partially oxidized and contains a considerable amount of polyphenols. Tea polyphenols have been found to be powerful antioxidants that may reduce low-density lipoprotein ("bad cholesterol") oxidation and the formation of oxidized DNA metabolites (i.e., free radicals), contributing to lower risks of cardiovascular disease and cancer, as well as decreasing body weight.

Obesity-news has provided extensive coverage of weight loss studies on green tea, oolong tea and other tea products. See the following articles and resource pages on our site:


There are literally dozens of weight loss supplements that do not work. Generally Obesity-news does not write about products which are completely ineffective. The articles below discuss products that have questionable results in humans, or results that so far have only been shown in animals. The only exception is in the case of the product chitosan, which was the subject of several studies comparing it to the prescription medication Xenical.

If a supplement or OTC medication has shown positive results in either a published study or presentation given at a major medical conference, you will find coverage of it in Obesity-news, and it will be referenced in the section above.


Chitosan is marketed as a "fat binder" by supplement companies. It is made from the shells of shrimp and other marine exoskeletons. These companies say that "Chitosan affects fat in the stomach before it has a chance to become metabolized. It dissolves in the stomach and converts to a gel which "traps" fat, thereby preventing its absorption and subsequent storage." The proof for this claim? A study conduced at Ars Medicina in 1994, referred to at the "Helsinki study", in which individuals in the chitosan group lost "8 percent of body weight in 4 weeks".

However, no published study indicates that Chitosan reduces weight in humans. A Japanese study showed that chitosan decreased weight gain in mice fed a high-fat diet, but a recent human study indicates that chitosan does not reduce body weight. In the double-blind placebo controlled study, thirty-four overweight volunteers given either chitosan and placebo capsules for 28 days while maintaining their normal diet. Neither group lost any weight. Medications which block fat absorption, like Xenical, cause greater weight loss in the active medication versus the placebo group when all subjects are maintained on the same diet.



Chromium is an essential trace mineral which maintains normal blood sugar balance. It is the most widely sold supplement outside of calcium. Supplement companies claim that chromium promotes weight loss, increases muscle mass, protects against heart disease, osteoporosis and may even increase your life span. Detractors say that chromium has no proven benefits except to a small population of individuals on parenteral nutrition.

The basis for the assertion that chromium produces weight loss are two studies conducted in the 1980s on college football players in a weight training program. The group supplemented with 200 mcg chromium picolinate over a 6-week period had a significantly higher increase in muscle mass and a greater loss of body fat than the placebo group. However, these study results could not be reproduced in later trials using more sensitive methods of determining body fat. Other studies indicate that chromium may be useful in enhancing insulin action in type-2 diabetics, but no weight loss was reported.


Garcinia cambogia

Several studies show that hydroxycitric acid (HCA) derived from garcinia cambogia decreases appetite, reduces food intake, and inhibits fat synthesis in animals but there is not much evidence to support that it is effective in humans save for one 1995 study in a Spanish language non peer-reviewed journal. A 1999 study found that a commercial brand of HCA was no more effective in reducing weight in humans than diet and exercise alone. Several rebuttal letters questioned the methods used in this study, including the administration of a high-fiber diet which may have interfered with the efficacy of the product. Detractors of the study claimed that bioavailability of the product may also have been reduced, as many commercial products contain high levels of calcium. But despite the protests, there is no credible evidence showing that HCA produces weight loss in humans, and a second controlled study published last year found no difference in appetite or weight loss in subjects given HCA or placebo.



Hypericum, also known as St. John's Wort, is a serotonin reuptake inhibitor (SRI) that has been found useful in controlling mild cases of depression. There are no studies showing that it has an effect on weight loss. Nonetheless, the manufacturers of a product called "Herbal Phen/fen" combined ephedra with hypericum in an effort to come up with an OTC product as effective as the prescription combination of phentermine and fenfluramine. (Fenfluramine was withdrawn in 1997).

Several physicians who gave Herbal Phen/fen to patients in their weight loss practice reported positive results, but no controlled clinical trial has tested the efficacy of hypericum alone, or compared an ephedra product without hypericum to one containing St. John's Wort.



Leptoprin is a brand name for a weight loss supplement produced by AG Waterhouse that carries a hefty price tag, $153.00 a month. The name leads consumers to believe that the product contains leptin, which it does not. So what does Leptoprin have in it? If you link to the company web site, or to the numerous sites selling this product, you're not going to find out.

However, the 3 fat chicks got the labels for both the leptoprin and leptoprin stimulant free products, and reported the ingredients on their web site. The stimulant variety of leptoprin is basically an overpriced version of ECA stack with numerous additional ingredients thrown in, including green tea, l-tyrosine and calcium. The 3-fat chicks conclude that the calcium is what leads to weight loss in this product, but it's most likely the caffeine, ephedrine, acetylsalicylic acid (replacing aspirin), and the green tea. Without any vitamin D in this supplement, the calcium is unlikely to be properly absorbed. Leptoprin stimulant free contains a variety of supplements that have no studies clearly linking them to weight loss, including garcinia cambogia, scutellaria root, bupleurum, and epimedium. Clearly, neither of these products is worth $153.00 a month.


Melatonin is a hormone produced by the pineal gland that mediates circadian rhythms and other physiological functions. Melatonin synthesis and secretion decrease significantly by middle age and this decline is associated with the increase in visceral adiposity that occur with aging, especially in men.

In a 12-week rodent study, rats given melatonin experienced reductions in body weight, visceral fat, plasma leptin and plasma insulin levels. However, the effects of daily melatonin administration on energy balance in humans have not been determined.



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IMPORTANT: All information in this publication is believed to be accurate and true. Publisher is not liable for omissions or inaccuracies. Information in this newsletter is for educational purposes only and should not be construed as medical advice, or be used in lieu of consultation with a health care provider.