Weight Loss Drugs: Are They Really Effective?

Seems at least once a week one of my patients asks me about the safety and effectiveness of some new diet formula they saw advertised on TV or the internet.  The answer is a mixed bag of yes, no and maybe, depending on the ingredients in the formula and how they’re being used.  If you’ve got a few pounds to lose, it’s only natural that you might be intrigued and tempted to try one of these formulas.  So, allow me to share with you some information about a few common weight loss formulas out there, my recommendations, and let you to decide for yourself if you would like to try any.

Prescription Formulas

There are many prescription weight loss pills available, some control hunger, others rev up your metabolism, and still others play around with your insulin level to encourage weight loss. I feel that prescription weight loss formulas have health risks associated with using them. I would say, just leave the prescription formulas alone.

Over-The Counter Formulas

There are dozens of weight loss formulas out there.  Most of them are herbal based. Here are some of the most common ingredients in these weight loss formulas, their function, and their health risks:

Metabolism boosters/Fat Burners:

  • Green tea extract – helps you burn fat by ramping up your metabolism. A downside is that green tea extract contains a lot of caffeine and could cause some negative effects such as diarrhea, dehydration, heart palpitations, and nausea.
  • White willow bark – an herbal derivative that aids in raising metabolism levels. It is also the herb that aspirin is derived from as it contains salicin, a natural pain killer. Often found in “stack” formulas, it doesn’t do much on its own.  If you are allergic, or have reactions to aspirin, you will want to avoid white willow bark as well.  Like aspirin, it can decrease blood clotting and may interact poorly with prescription medications you may be taking.
  • Bitter orange – used in TCM (traditional Chinese medicine) for centuries for many conditions including weight loss. It contains the chemical synephrine which is similar to ephedrine in action, i.e., it revs up your metabolism like drinking caffeine.
  • Caffeine – boosts metabolism and can help you sustain exercise so you burn more fat and calories. Too much can dehydrate you, cause heart palpitations, jitteriness and insomnia.
  • Ephedra – the ban on this supplement was lifted not long ago but it has too many problems associated with it to use safely.
  • CLA (conjugated linoleic acid) – clinical studies have proven this formula effective in burning fat and preserving muscle.  A little over 3 grams of CLA a day (3,400 mg) is needed to produce these beneficial effects. Possible side effects may be loose stools and nausea in some people but can be prevented if taken with food.
  • Garcinia cambogia – contains HCA, hydroxycitric acid, which inhibits the body’s ability to store fat. No real known side effects, unless taken in very high does, but may have a laxative effect or cause  stomach upset if too much is used at once.

Appetite controllers:

  • Hoodia – discovered in Africa, it was used by Bushmen to stop hunger pangs on long journeys. The real thing used in Africa may be a lot stronger than the manufactured type sold as a weight loss aid and depends on the integrity of the brand you buy and how they process the Hoodia. Some can be very expensive.
  • Irvingia gabonensis – from the West African dika nut, initial studies showed weight loss in the group studied.  However, may have been due to decreased food intake, and may take as long as 90 days to kick in.

Carbohydrate/Sugar/Fat Blockers:

  • Phase 2 (white kidney bean extract) blocks carbohydrates from starches, i.e., pasta, potatoes, bread, corn from being absorbed.
  • Alli – (Orlistat/Xenical). You may have seen TV ads. Weight loss occurs as it blocks a percentage of the food you eat from being stored as fat and moves it quickly out of the intestines. In 2009 FDA received reports of liver injury, and investigations are underway.
  • 5-HTP – increases “feel good” serotonin levels in the brain so you can stay on a carb-restricted diet longer to help lose weight.  Also helps you sleep. As an adjunct to a healthy, lower carb diet, it can have some value in limited amounts.

Insulin Stabilizers:

  • Cinnamon – recent clinical studies were very promising in cinnamon by decreasing blood sugar levels and stabilizing insulin levels. Helps decrease belly fat by decreasing insulin. There is conflicting information, however, that common cinnamon, made from cassia bark, may be toxic to your liver in doses higher than 1 gram as it contains Coumarin. Ceylon or Sri Lankan cinnamon does not contain Coumarin.  Best to stay in the 1 gram (or two 500 mg capsule) limit.  Diabetics should use with a doctor’s supervision.
  • Chromium – a mineral, helps utilize insulin better, decrease belly fat deposits.
  • Gymnema sylvestre – an herb used in India for decades as a weight loss aid to lower blood sugar levels in diabetics, it is usually one of the ingredients in weight loss formulas along with chromium and cambogia gordonii. The American National Institute of Health deemed it helpful in controlling blood sugar levels in diabetics.  However, diabetics should use under a doctor’s supervision.


  • Herbal slimming teas, or “Dieter’s Tea” – contain rhubarb and senna which are powerful laxatives.  These can be used sparingly/diluted as a pre-diet colon cleanse, but do not use these types of teas regularly. They can cause diarrhea and deplete your electrolytes which make your heart fire incorrectly with palpitations, etc.
  • Bowel cleansers – contain a lot of herbal ingredients like rhubarb, senna, cascara sagrada, and others. These work to clean the bowel of build up waste and can result in a few pounds of weight loss on the scale, but this is mostly water and waste loss and not fat.  Useful as a pre-diet colon cleanse but not as a real fat loss solution.
  • Acai berry – another detoxing agent, ads for it are all over the internet touting huge amounts of belly fat loss and almost always by people who are selling it.  The benefit of acai berry is in its vitamin, mineral, antioxidant content. The downside; it’s not a magic bullet for weight loss.

Hormone/Sensory Formulas:

  • HCG (human chorionic gonadotropin) – HCG is a hormone produced during pregnancy present in urine.  It is touted to ramp up metabolism so that you burn a lot of fat quickly. The downside to this routine is that you have to go on a very low calorie diet to accompany it, which may be impossible to tolerate, and is not cheap. Best used under a doctor’s supervision.
  • Sensa – works on your sense of smell to decrease the amount of food you eat.  If you’ve ever had a bad cold and couldn’t smell you know how much your taste and desire to eat was also affected. Basically same principle. If you eat less, you lose weight.

My Recommendation

Weight loss is not all that complicated. It’s basically a matter of eating less, but nutritionally dense, low sugar, amounts of food, and moving more, i.e., getting more exercise.  I feel the best, natural supplements to aid weight loss are vitamins and minerals that support healthy fat and sugar metabolism like the array of B vitamins, L-carnitine, Vitamins C, E, D, and Omega-3’s.


Mark Rosenberg, M.D.

Dr. Mark Rosenberg, MD is a Phlebologist in Boca Raton, FL. He is affiliated with Boca Raton Regional Hospital.

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