This product has been talked about a lot in the beauty community and I see why. It is an excellent vitamin C serum. My advice is to use this right away. I bought a back up of this and left it stored for a while, when I opened it sadly it has gone bad so you have to be careful and follow the storage instructions.

I've been using this for more than a month now, and I did notice a bit of lightening. Maybe if I will continue it, (or if I try the C.21 one?) I'd see more visible results. I was afraid it'd be harsh on my skin, but other than some heat, I didn't feel any stinging at all.

i love this serum, but not good smell i dont like the smell

It is a  good product. Does its job :)