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Do Weight Loss Pills Work?

Written by Jim LaValle, R.Ph., CCN

A recent headline from a study on hoodia (an African plant often used in weight loss pills) once again has people asking me about weight loss supplements.  Sales of the “weight loss in a bottle-type supplements” sure don’t seem to be slowing down.  Do they work?  Can they help, at least?  Here’s what you need to know.

What is hoodia?   Does it work?

The story of hoodia is somewhat of a cautionary tale when it comes to weight loss products.   Hoodia is a succulent plant that is used by the people of the Kalahari Desert to lower appetite and thirst when food and water are scarce.  This unique plant and its action of helping to reduce appetite caused some industry players to spend millions of dollars evaluating the herb to see if it was effective for weight loss.   An early study looked promising.  It was a fairly small, unpublished study which found that when people were given hoodia, they consumed 30% fewer calories than people given placebos.   This led to further study by Pfizer, who found that the active ingredients in the plant were very difficult to isolate and, much to their dismay, that hoodia could cause liver damage. Because many weight loss supplements include hoodia as an ingredient, I was very glad to see that another human trial was finally completed recently. 

The trial gave clinical dosages of a purified hoodia extract to 25 women with high body fat percentages, and compared their calorie intake and weight loss to 25 women given a placebo product.  The study found that the hoodia group had reduced their calorie intake by 24% over baseline while the placebo group had decreased their calorie intake by 18%. Interestingly, these reduced calorie intakes did not lead to any loss of body weight or body fat.  In addition, while the placebo group had no side effects, the group taking the hoodia supplement had increases in blood pressure and heart rate as well as increased bilirubin and the liver enzyme called ALP.  Also, the group taking hoodia had many other side effects including headaches, nausea and vomiting.  The side effects combined with the lack of efficacy for weight loss obviously led the researchers to conclude that hoodia would not be a good candidate for a weight loss product.[i]

Now, what is so amazing to me is that the studies finding potentially damaging side effects have not stopped the manufacturers from using hoodia as an ingredient in their weight loss supplements, or at least saying the products contain hoodia.  A lab analysis found that of 13 products tested, only 6 actually contained hoodia,[ii] which, in this case, is probably a good thing. 

Are there any weight loss supplements that work?

Let me put it this way. There may be some that are somewhat effective for some people depending upon whether the ingredients in the product happen to address your physiological needs, e.g., insulin resistance, which is a culprit in a lot of weight gain. 

Most weight loss supplements are a mixture of active ingredients, and there is usually a good rationale for the ingredients.  Some of the most common ingredients have a decent amount of research, but there is still a big BUT.  Most products do not contain enough of the active ingredients to get the same results seen in studies.  In addition, it can be hard to tell exactly how much of an active ingredient a product contains because the manufacturers will use several ingredients together as a part of a patented blend of ingredients, which they lump into a name they make up.   Here are some examples:

Blood sugar-regulating ingredients

Many of the ingredients in weight loss supplements are supposed to act on blood sugar and insulin regulation.  This is a good mechanism of action because insulin resistance truly is a factor in weight gain.

Chromium – Helps insulin work better for reduced insulin output.  Typical dosages I’ve seen are 10 to 120 mcg.  Studies have used up to 2000 mcg in severely insulin-resistant diabetics.  A study showing some efficacy for reducing food intake and slight weight loss (about 1 lb. in 8 weeks) was 1000 mcg.[iii]

Vanadium – This has insulin-like action and improves blood sugar and cholesterol profiles.  Studies have used anywhere from 250 mcg to 150 mg,[iv] a much larger “research only” dosage.  The safe upper limit is 1.8 mg.  Weight loss products I’ve seen have contained anything from 10 to 500 mcg, dosages that are much lower than the studies.

Alpha lipoic acid – Has been studied extensively in diabetics for insulin resistance.  The effective dosage is 600 mg two or three times a day.  This is one where the usual dosages in weight loss supplements are woefully lacking, containing anything from only 10 to 100 mg.

Magnesium – May contain anywhere from 20 to 100 mg.  Effective dosages are 250 to 500 mg per day minimum.

Gymnema sylvestre – This is an herb, which actually has a good bit of research showing efficacy for blood sugar regulation with human studies.  Studies showing that it may reduce cravings for sweets and help weight loss have been rat studies.[v], [vi]  Dosages in studies are from 250 mg to 600 mg one to three times a day.  Dosages in weight loss products are sometimes not clearly identified, but they typically aren’t over 200 mg.

Increased metabolic rate

Other ingredients are substances that have been shown in studies to increase metabolic rates slightly, like green tea, caffeine and garcinia cambogia.

Green tea – This is an ingredient with some of the most impressive studies for weight loss.  One of the highest quality green tea products is a green tea phytosome; a study of this particular product showed that when taken along with a low-calorie diet, it led to a 14 kg weight loss in 90 days compared 5 kg weight loss in the diet-only group.[vii]  The dosage in this study was 250 mg twice a day.  Again the key here is quality and quantity.  Green tea products should contain 90% polyphenols and at least half of the polyphenols should be the active compound known as EGCG.

Caffeine – This is an ingredient that is sometimes way overdone, with some products containing the equivalent of 30 cups of coffee per day.  Needless to say, if a product contains caffeine it can cause a person to feel very jittery and unable to sleep. Effective dosages have ranged from 80 to 200 mg per day.  I’ve seen products containing anywhere from 40 to 1400 mg.

Stress reduction/craving reduction

Rhodiola – Rhodiola is a great ingredient that really has been shown to help reduce the effects of stress on the body.[viii]  The effective dosage range is 150 to 300 mg, one to three times a day, and these should be standardized extracts that contain at least 3% to 5% rosavins.  I have seen products that contain only 50 mg and do not state that they are standardized.

These are just a few examples.  I have seen many diet products with a mixture of these and other ingredients, such as cinnamon, or antioxidant ingredients such as resveratrol and curcumin.  For good ingredients like these, the bottom line is that the dosages have to be high enough.  Then there are the unproven ingredients like acai.  It is an antioxidant,[ix] but it’s just not proven for weight loss, no matter how many claims you see.  Then there are ingredients that may have some study like the thermogenic products bitter orange (citrus aurantium) and garcinia cambogia, but they do cause jitteriness, which means they are stimulants and over time can be hard on the body.  Side effects can include increased heart rate and blood pressure.

The bottom line: Use caution and look for high quality.

When it comes to products available in over-the-counter retail outlets, I would be very cautious. The unfortunate truth is there is no easy weight loss miracle pill, and there have been many instances of adulteration in products off of retail store shelves and Internet products.  Are you willing to sacrifice adrenal effects, burnout, sleep problems and even high blood pressure in exchange for hope of a few lost pounds?

However, some high-quality products are available that can give you an edge if they contain adequate dosages of good ingredients.  For example, I know several professional practices that carry products with blends of some of the better-proven ingredients.  (Not to get in a cheap plug, but Life Time’s Lean Source is one such product.  It contains one of the best proven ingredients, green tea, along with blood sugar-supporting chromium, muscle-building CLA and thyroid-supportive 7 Keto DHEA.)  But these professionals also take the time to evaluate and address metabolic issues that may be contributing to weight gain. 

As you have hopefully read in many articles from Life Time, the reasons for weight gain are many and varied; therefore, the solutions to weight loss will be multifactorial.  Your best hope for long-lasting weight loss is identifying underlying metabolic disruptions and taking steps to address them.

This article is not intended for the treatment or prevention of disease, nor as a substitute for medical treatment, nor as an alternative to medical advice. Use of recommendations in this and other articles is at the choice and risk of the reader.

[i] Blom WAM, et al.  Effects of a 15-d repeated consumption of Hoodia gordonii purified extract on safety, ad libitum energy intake, and body weight in healthy, overweight women:a randomized controlled trial. Am J Clin Nutr Oct 12, 2011.


[iii] Anton SD, et al. Effects of chromium picolinate on food intake and satiety. Diabetes Technol Ther. 2008 Oct;10(5):405-12.

[iv] Cusi K, Cukier S, DeFronzo RA, Torres M, Puchulu FM, Redondo JC. Vanadyl sulfate improves hepatic and muscle insulin sensitivity in type 2 diabetes. J Clin Endocrinol Metab. Mar2001;86(3):1410-1417.

[v] Imoto T, Miyasaka A, Ishima R, et al. A novel peptide isolated from the leaves of Gymnema sylvestre - I. Characterization and its suppressive effect on the neural responses to sweet taste stimuli in the rat. Comp Biochem Physiol A 1991;100(2):309-314.

[vi] Luo H, et al. Luo H, Kashiwagi A, Shibahara T, Yamada K. Decreased bodyweight without rebound and regulated lipoprotein metabolism by gymnemate in genetic multifactor syndrome animal. Mol Cell Biochem. 2007 May;299(1-2):93-8.

[vii] Di Pierro F, et al. Greenselect Phytosome as an adjunct to a low-calorie diet for treatment of obesity: a clinical trial. Altern Med Rev. 2009 Jun;14(2):154-60.

[viii] Hung SK, Perry R, Ernst E. The effectiveness and efficacy of Rhodiola rosea L.: a systematic review of randomized clinical trials. Phytomedicine. 2011;18(4):235-44.

[ix] Mertens-Talcott SU, et al.  J Agric Food Chem. 2008 Sep 10;56(17):7796-802. Epub 2008 Aug 12.

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Reader Comments (7)

How one can know which diet pills having Great quality and does't having any side effect . Can you explain ?
I mean can tell what are the checklist to buy diet pills online

April 23, 2012 | Unregistered Commenterrohni

This post is very interesting and it also helpful for us. liking stuff like this blog as well as this has now given me Some inspiration To succeed, ever so Appreciate it.

April 25, 2012 | Unregistered Commenterjon smith

I am a 48 year old woman who is easily 20 pounds overweight. I am exercising 3-5 times a week (30-60 minutes of varied activities usually in zones 3 & 4) and eating mostly proteins, fruits, and veggies. I'm taking supplements that include CoQ10, LTF Omega 3 fish oil, calcium and others as well as drink mostly water and unsweetened tea, but still only lose 1/2 to 1 pound a week. Any ideas as to why my weight loss is SO SLOW? What else can I do?

April 25, 2012 | Unregistered CommenterEASC

@EASC: First, there's no standardized rate of weight loss. Many weight loss sites will tell you if you create a calorie deficit of 1000 calories a day, 7000 calories a week, you'll lose an average of 2 pounds of fat per week, but in reality, it rarely works out that way, even in clinical research settings. If you're consistently losing 1/2 to a pound each week, it's certainly progress. That said, the answers to a few more questions could be helpful.

When you say 30-60 minutes of varied activities, what are you doing? What is the total time each week and does that vary? If so, it could influence your results.

How much time are you spending in zone 4. The more time you spend working above anaerobic threshold, the more you train your body to burn sugar rather than fat. You may be working at a higher intensity level, but that's not always best for some people's weight loss efforts.

When you say "mostly protein, fruits and veggies," what else do you eat in a typical day? Often, people don't realize how much sugar they end up eating with little handfuls of snacks during the day. I'm not suggesting that's the case, but the term "mostly" made me think there could be some other foods mixed in. How much protein, vegetables and fruit? What about a multivitamin?

For beverages, you also mention "mostly" water and unsweetened tea. Are there other beverages?

One last question, at 48 years old, have you had your hormones and other metabolic markers checked?

Sorry for more questions than answers, but everyone is different and without more detail, it can be hard to find an answer.

April 26, 2012 | Unregistered CommenterTom Nikkola

In answer to "How can you tell quality?" - this is a really hard issue to address in a short answer. But here are some pointers. I will speak to weight loss supplements specifically and supplements in general. There have been a few incidences of weight loss supplements and supplements for cholesterol contaminated with drugs. Most of the problem products were internet sales. There are sites that make big claims for supplements and then lead you to a link to order. They are not known brands, and they provide no manufacturing info and even label/ ingredients info is often not there. DO NOT ORDER anything of that nature, ever, a weight loss pill or any dietary supplement. Internet sales of this type have been fraught with problems. There have been a couple of problems with diet pills sold in big-box retail nutrition stores.

For a "Weight Loss" pill, to avoid the problems of low ineffective dosages or possible quality issues, I would shy away from a retail experience. I would also not buy one with Hoodia as an ingredient. However a professional product designed to aid weight loss may help. For these supplements to work, they have to have adequate dosages of the active ingredients and the ingredients have to match your body's needs. If one emphasizes, blood sugar support but your issue is stress and appetite control, it may not help that much. That's why I outlined the types of ingredients and what they address.

Now to speak to dietary supplements in general, there is a hierarchy of quality. The highest quality dietary supplements are those manufactured by companies that sell only through practicing doctors or facilities with other licensed health professionals. The manufacturers of professional product lines make a commitment to very high quality control and effective dosing.

As for dietary supplements in general sold in different retail venues, ie pharmacies, health food stores, etc there is a tremendous record of safety. However, if a product is real inexpensive, they are cheaper for a reason. Generally the raw ingredients are lower quality. I know people who have bought brands from health food stores, which they have gotten results from and that is the bottom line. Do you feel better and notice results? Cheaper multivitamins often contain cheap ingredients like synthetic vitamin E (seen on a label as dl-alpha tocopherol versus just d-alpha tocopherol for natural vitamin E). It's useless and may even slightly raise some health risks. Beta carotene is not particularly valuable and may raise health risks in smokers. Any product that wants to use carotenoids, should use mixed carotenoids. These are just a couple of examples. These are issues that higher end retail and professional products know and address.

Also, look for well-known manufacturers - names that have been around for years. If you never heard of the company try to find out about them. The key is to look for name brands with manufacturers that give all their contact info, so they can be reached in case of any problems. Manufacturers that go to lengths to let you know their quality control, what is in their products, what they are for, what studies are on the product ingredients, where they manufacture, how they test their raw ingredients for purity, how often they have independent lab analysis done to ensure purity and accuracy of label dosing info etc.

In answer to SLOW weight loss - Tom steered you in the right direction. In most cases when I see really slow weight loss there is an underlying metabolic issue. The most common are insulin resistance, thyroid, sex hormones and food allergies. The signs of insulin resistance are waist bigger than hips and blood sugars that trending high with high cholesterol. The blood sugar supporting nutrients are usually very helpful: they include chromium, magnesium, zinc and alpha lipoic acid as well as some herbs like bitter melon and gymnema. Thyroid function can also sometimes be the issue. Good thorough thyroid testing is necessary and then if thyroid medication is needed, I recommend working with a doctor who will be willing to let you try different medications until you find one that works for you. If a med is started and symptoms like cold hands and feet are not improved or you don't see some weight loss with improved energy, try another med. The other issue can be hormones. See if you can find a hormone doctor in your area. One question to ask is if they take other metabolic issues like stress hormones and insulin resistance into account. Both of these issues can affect and disrupt sex hormones. If you don't address them, you can't be as effective in correcting sex hormones. Thankfully you are losing some weight, but it is probably worth doing more exploration into some of these issues if you haven't already. Sometimes, it is a simple matter of increasing exercise effectiveness. Interval training is very effective for weight loss. Diet may also need a bit more refinement and experimentation to find what works for you - increasing protein helps appetite and holds glycemic response down. It sounds like you are trying to do that. Be careful, with red meat. I have seen intake of too much conventionally raised red meat stop weight loss in some people. Also make sure to load up on vegetables, salads and greens at lunch and dinner, but be careful on fruit; it is easy to overdo. I prefer 1 or 2 servings per day as a limit. And a little starch at dinner may be helpful. While, grain free paleo is effective for some people, a recent study found that people who ate a small serving of potatoes or rice or other whole grain like quinoa lost more weight than those on starch-free plans. Also make sure you are eating healthy fats, like olive oil, coconut oil and or a little butter. They help mood, satiety and gut health. Finally, you may have food allergies, so some testing for that may be helpful. Here are a couple of examples. Some people get going on a certain nut for a snack, like almonds for example, and then become allergic to them. I had a woman who changed her diet to a protein, fruits, and veggies diet and couldn't lose much weight. So we tested and found that she was allergic to eggs. She got rid of them and more weight started coming off. Start with simplest and easiest changes first and go from there. Like diet and exercise tweeks. If that doesn't help, evaluate your symptoms. For example, if you have signs of insulin resistance, a blood sugar support supplement may help. If you have signs of low thyroid, see about getting tested for that first. I hope that helps.

Thanks for all comments and posts.

April 30, 2012 | Unregistered CommenterJames LaValle, R.Ph.

The title of this post is misleading, as the post goes on to discuss over the counter supplements. "Weight loss pills" implies medications.

Over the counter supplements are not regulated by the FDA as they are sold as "food." Sorry, but there are no foods that we eat that cause weight loss, certainly not in a safe way.

However, there are several prescription and 1 OTC medications that DO help very dramatically with weight loss. Phentermine has been used safely for 56 years, helping individuals with weight loss. Patients statistically lose about 5.5% of their body weight with Phentermine, but when combined with more aggressive medical diets, I frequently see patients losing 20-30% (20% of weight is the average weight loss with a lap-band surgery). So, with medical treatment, prescription "weight loss pills" are extremely effective. There are several other choices, including: Tenuate (similar to Phentermine), Phendimetrizine, and Xenical. Over the counter, Alli (OTC Xenical) helps individuals lose about 2.5% of their total body weight, and can improve weight loss with a properly structured diet.

Although Phentermine, Phendimetrizine, and Tenuate are only approved by the FDA for "short term use" (12 weeks in 12 months), most weight loss physicians will consider longer treatments for appropriately low-risk individuals. Current clinical trials being conducted by the Pharmaceutical Companies Vivus, Orexigen, and Arena promise better options with long-term approval. Qnexa, a combination of Phentermine and Topiramate, helps individuals lose an average of 10% of their body weight, and safety trials have been carried out for a full 2 years (double the typical length of time to qualify a drug for 'long-term'). With a recent vote of 20 to 2 in favor to approve it, it is highly like that Obesity Medicine physicians such as myself will be able to offer this to patients after the FDA's ruling later this year, currently scheduled for July 17th.

Having recently attended the most current medical education courses at The Obesity Society, The American Society of Bariatric Physicians, and even the Harvard Practical Approaches to the Treatment of Obesity, none of the 'foods' has good evidence that it is helpful for weight loss, including the ones mentioned in this article.

So "Do weight loss pills work?" Absolutely - just don't consider OTC supplements "pills."

Anyway, sorry to get on a pedestal, but I think it is crucial to differentiate between prescription "pills," OTC FDA-regulated "pills" and food.

May 6, 2012 | Unregistered CommenterEthan Lazarus

My friend has a belly issue as well. He's been through a lot of diet and work out plans. None of those methods actually worked for him. So, I decided to help him get through his struggles. I gave him diet pills from Bangkok. Along with that diet pills, I also taught him how to get a six pack in a month. Within a month of exercise and diet, he gained a tremendous development. Up to this time, he's doing the exercises I taught me. He also discontinued taking the diet pills I gave him.

June 4, 2012 | Unregistered CommenterGeorge

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