 We lose it either due to wear and tear or age, and so we start getting problems. The more that we find pain relief, the more pain relievers we use, the more we're going to use these joints, and then we're going to wear out more bone. And they've noticed this. People who chronically use pain relievers are going to have more bone wear. So what you need is the actual cushioning back there to lubricate the joint, and that's what HA does. That's what HA is. The doctors call it synovial fluid.