On Sephora.com it states that a rain drop amount of product will cover the whole lid, trust me you'll need a lot less than that for both eyes. This product is great, applies extremely smoothly. I also like the tube vs a pump or a wand.
It does improve the wear and look of my shadows. The ones that used to crease, crease no more. Totally worth the purchase.
UPDATE : It does hold my shadows in place, but the product keeps splitting on me. Sometimes all that comes out is some oil type stuff, even when I shake it up. I'm loosing the love I had for this little tube.