The form and the source of the supplements you use are keys to the benefits you reap. You have to go the extra mile to distinguish the highest quality from the pale imitations. Quality appears rare in today's rapidly growing health supplement industry. You can make a point of using well-established brands, though off brands might be perfectly fine, and a well-known name isn't by itself a guarantee of quality. Studies have shown that many of the leading brands available may not be performing as expected. It is now harder than ever to know which brand to trust your health to.
Quoted from the book "No More Knee Pain" by George J. Kessler :
"When Canadian researchers checked the amount of active ingredient in fourteen different glucosamine products, they found an actual content ranging from 300 mg to 150 mg - though eleven of them were labeled as containing 500 mg. Without knowing how reliable a product is, it is hard to ensure not only that you get the appropriate dose, but also the activity of the product is good."
Hopefully, the Health Sciences Authority in Singapore will one day step in to provide some regulations and guidance of supplements that will allow consumers to be informed and confident about exactly what they are buying. Until the day comes, you can look for companies making pharmaceutical grade supplements in GMP registered or FDA registered facilities. You can also rely on ConsumerLab.com for independent review.