1,000mg — the cartilage building block at the center of the formula.
Glucosamine Sulfate is the largest ingredient in JointBrex by weight, an amino sugar the body uses to build glycosaminoglycans, the water-holding molecules that give cartilage its cushioning.
The sulfate salt is the form used in most of the European trials that reported a benefit, and 1,000mg sits at the dose scale those studies used.
It's worth noting the wider glucosamine and chondroitin evidence is genuinely mixed, with some large trials, such as GAIT, reporting no overall benefit against placebo.