Dr Covington answers your questions.

This question comes from a patient who came for a new weight loss visit. She picked up PGX from a local retail pharmacy and started taking it after a friend tried it for weight loss. At the time, I was not familiar with PGX but promised her that I would look into it and give her my opinion.

What is PGX?

PGX is available in powder or pill form. When searching for supplements, always look at the ingredient list. The drawback of this of course is that not all companies list the full ingredients or worse, some companies may falsify ingredients to mislead consumers of ingredients that are not truly in the product. When checking the ingredient list for PGX (which is PolyGlycopleX) the listed ingredients are: konjac root, xanthan gum and sodium alginate.

Konjac Root – is the root of the Konjac plant – a Asian (found in China, Japan, and Indonesia) plant that contains a soluble fiber glucomannan.

Xanthan gum – Commonly used “stabilizer” that keeps food or supplements from separating

Sodium Alginate – Natural substance extracted from brown seaweed forms a gel, used in substances to produce a gelatin or gelatinous structure.

The active ingredient in PGX is glucomannan, which is fiber. Glucomannan is also the active ingredient of Lipozene, a non-FDA approved weight loss medication whose parent company was fined 1.5 million dollars by the Federal Trade Commission for making false weight loss claims.

So, although I don’t know a lot about PGX, I know quite a bit about fiber. Fiber comes in two forms, insoluble or soluble, and glucomannan is a soluble fiber. The difference between soluble and insoluble fiber is that soluble fiber absorbs water or dissolves and turns to gel whereas insoluble fiber does not dissolve and moves through the digestive tract.

Soluble fiber is found in fruits, vegetables, lentils, peas, grains (such as oat bran and barley), nuts, seeds, and psyllium.

PGX (active ingredient: glucomannan) boasts the following weight loss claims:

  • Reduces hunger
  • Increases satiety and fullness
  • Reduces glucose and insulin spikes
  • Aids in diabetes control
  • Lowers cholesterol
  • Aids in weight loss

The instructions for PGX include taking 3 times a day before each meal with at least 4-8 ounces of water.

Benefits of Fiber

benefits of fiber for weight loss

Fiber aids in satiety and fullness by slowing food transit in the stomach and intestines and stretching the stomach lining. Soluble fiber slows the absorption of glucose which improves glucose levels and reduces the spike of insulin. The latter is beneficial in diabetes and insulin resistance. Improving insulin resistance and blood glucose improves cholesterol and fiber has been proven to reduce cholesterol in many scientific studies, the British Journal of Nutrition demonstrated that addition of psyllium in the diet was enough to reduce cholesterol levels. One of the major cautions with soluble fiber is that it can get expand in the digestive tract so substances like glucomannan or psyllium husk are not recommended for bariatric surgery patients, patients with GI motility disorders such as achalasia, esophageal disorders, or gastroparesis. It is important to ingest fiber with plenty of water to reduce the chances of it getting stuck in the wrong part of the digestive system.

The health benefits are true for fiber in general, PGX or glucomannan likely has no more benefit from any other commercial fiber product; however, the clinical studies with glucomannan and weight loss are mixed. Several studies showed no impact on weight loss or body composition. In terms of weight loss, a high fiber diet was shown in a study by the Annals of Internal Medicine to yield an average of 6 lbs in 1 year – when 30 grams of fiber was ingested daily (however 7 individuals in this group also unfortunately developed Type II diabetes).

The problem, however, with recommending a product like PGX is that it is not regulated or approved by the FDA. This means that any manufacturer can list glucomannan as an ingredient but there is not proof that it exists in the product and no studies to determine if the product is legitimate, effective, or safe for consumption.

This substance used in candy (konjac candy) was banned in the US and Canada due to choking reports and several deaths in young children and elderly.

As an alternative, increase fiber in the diet and supplement with well known fiber supplements such as psyllium husk or wheat dextrin. If looking to add a FDA approved weight loss medication to your diet and exercise regimen, I recommend consulted an expert in weight  loss, like a bariatrician or schedule a new patient visit in our office.

Dr Covington

My Top Recommendations for Fiber Supplements are listed below:

Tropical Fruit Fiber Drink and Lemon Fiber Drink in the Online Store

Click here for Tropical Fruit Fiber Drink 

Click here for Lemon Fiber Drink



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