Question: I heard that one of your chondroitin products failed ConsumerLab.com’s recent tests. What kind of testing do you use?
According to ConsumerLab.com, a Swanson glucosamine and chondroitin product (SW889) allegedly failed their testing; ConsumerLab.com claims the product contained only 8% of the label-claimed chondoitin.
We guarantee that this product contains the label-claimed amount of chondroitin as proven by third-party testing using the size-exclusion chromatography method. Independent testing with the SEC method shows the amount of chondroitin in this product actually exceeds label claim:
Label claim: 250 mg per capsule
Test result: 279 mg per capsule
For many years, there has been extensive scientific debate about the appropriate method to test chondroitin due to its unique nature. Chondroitin is not a uniform, defined molecule but rather a polymer that exists in many polymer sizes. There are several methods available, and each looks at a different aspect of the molecule to determine the assay value. Our products are tested by an independent laboratory using the size-exclusion chromatography (SEC) method. This is a published method (in peer-reviewed journals) for testing chondroitin and similar polymers, and we feel it is the most appropriate testing method for the chondroitin used in our products. You may hear this method is non-specific for chondroitin and similar materials can “fool” the test. We would agree with that statement if a derivatization step were not included. The independent lab that we had test this product used a derivatization step [with 1,9 dimethylenemethyl blue (DMB)], which assures that the method is selective for chondroitin. Specifically, one molecule of DMB reacts with each of the chondrosine repeating units of chondroitin, and so the observed absorption at 525nm is directly proportional to the quantity of chondroitin that is present regardless of the polymeric molecular weight. Other sulfated polymers will react but will give yet different metachromatic shifts; thus if only observing the desired channel (eg 525nm) a signal is seen only if chondroitin elutes from the column and is derivatized with DMB.
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(Note: as per industry regulations, we cannot and will not answer medical questions, make treatment or diagnosis recommendations or comment on disease inquiries. Such questions must be answered by your doctor or professional health care provider.)
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