As for the closure: it had experienced many good shakers that the content will expire if and when you want to prepare the shake too fast and can not waste time. The trick is in fact, put on the lid without pressure and to turn it in the direction of opening until it snaps easily. Only then rotates in the closing direction, slowly and without pressure. Then, towards the end, it closes tightly.
The only times when fluid leaked, were when I was in a hurry and have tilted the lid fault of their own. You have to master this technique and be patient, then does not happen a something with this product here.