text:  The vitamin C and D combo, again, we call it our essential immunity. And most people probably take it for supporting their immune system. But you're right. Vitamin C is absolutely critical for collagen generation. And if you are low on vitamin C, that's not optimal when it comes to making cartilage. And the idea behind Joint Shell is to do just that, to make cartilage, to grow cartilage. And as we're about to get into, to maintain cartilage.