1,000 mg — The most heavily studied joint-support compound, a natural component of cartilage.
Glucosamine Sulfate is dosed at 1,000mg per serving -- roughly 72% of the formula's entire 1,383mg total by weight. It's the most heavily studied joint-support compound generally, and is frequently researched in combination with chondroitin for knee osteoarthritis specifically -- though that research usually uses more chondroitin than this formula contains (see the Chondroitin entry below).