I am 21 with oily skin.
I can say it gave me a more youthful look and a wrinkle that I get between my eyebrows when I am in the sun, disappeared faster than usual.
The smell is lovely. It reminds me of high-end products I used to have.
What impressed me the most was how well it sat under makeup. It worked like a primer. While I usually get oily after half an hour of applying tinted sunscreen, with this I stayed matte for hours. Indeed, it makes an ideal makeup base.
Now for the application, I applied it after toner and before moisturizer. Like you would apply any serum. It creates a sticky texture all over the skin, you wait for it to dry (it won't be sticky when dry) and then apply your moisturizer.
I remove one star because I don't like the product's packaging. I consider it tacky and kitschy, like all the company's, unfortunately.
I would buy it again for spot application on wrinkles, not on the whole face.

I have only had it for a week, but I am impressed. It absorbs immediately without leaving any greasiness, it is lightweight, and I feel that it "tightens" my skin and gives me a more refreshed appearance almost instantly. Also, even though I have sensitive skin prone to breakouts, especially now in the summer, it has not bothered me at all. Great value for money, I will definitely buy it again and try the rest of the products in the line.

After 6 months of use, I have to say that it is indeed an amazing serum. It fills in wrinkles and gives a nice natural look without shine. A must-have product!