Works

This is quite an expensive product but it smells great and lasts a while. I use it for my hyper pigmentation after my hormonal period spots. They seem to fade quicker with use. I use twice a day. I have used many bottles.

I used a whole bottle of this dark spot solution and the little bottle last very long. a little goes a long way(i needed about 3-4 drops for my face though.it's almost like an oil, but a little like gelee(slippery/sticky but in a good way) can't describe.i didn;t see results right away, it took me about a month(but that's normal,it's with everything that you can buy out there that it doesn't work overnight). i had acne scars and some dark spots in my face. let me say this,it made my scars less visible and dark spots were not this dark anymore.so it worked.but i expected to see more,i knew it couldn't "erase" everything. it didn't irritate my face.it's a nice feeling when i applied it. i applied this serum in the morning(before my daily moisturizer-a kiehl's product for sure) and in the evening(before my daily evening care product-an kiehl's product as well). so i applied it as the direction said, 2 times daily.the price is a little expensive, but that's with all kiehl's products. but i love them, because they are gentle to my skin and work! this product works really great and i recommend it. when my first bottle was empty i won one of the new L'oreal Youth Code Corrector Serum.so i changed from kiehls to this from L'oreal/(i still have another full kiehl's dark spot solution at home, and will use it again right after my youth code corrector is empty. but let me say that,i'm almost through my youth code corrector as well, and my skin looks like new,sure there are still some very light acne scars...but i can go out without make up now!!!i don;t know if the kiehl's gave me a great start for that, or if L'oreal corrector gave me the end results. i like the L'oreal a little more, it's 1. cheaper and 2. it's a crem and you need also only a small pump of it and it goes a long long way. i would say i finish my kiehl's spot corrector i still have here and after that i stay with l'oreal (saves me money and i think it will help to maintain where i am now and i like more that it is a creme).but kiehl's works and i'm a lover of kiehl's.

I also received a sample of this from there facebook promotion.You dont need much of this a little goes a long way and it lasted me a little over a week as well.I do not have dark spots on my face but the serum is lovely it glides on nicely and your face feels so silky.I love Kiehls products they are pricey however but worth it.If I had a problem with spots or discoloration I would probably buy this.I love the ingredients which are as follows from there website:

Activated C
A potent next-generation active, works faster than the leading dark spot ingredient. Penetrates rapidly to attack deep-set dark spots while preventing the formation of new discolorations for visibly more uniform skin tone and clarity.

White Birch Extract
A sugar derived ingredient known for its ability to restore hydration and nutrients to the dermis and epidermis layers of skin . This potent active increases skin elasticity levels and collagen production resulting in restored skin density, volume and thickness. Works synergistically with Activated C to facilitate discoloration correction for skin clarity

Peony Extract
Works synergistically with Activated C to facilitate the reversal of discoloration for skin clarity.

As always there are No Silicones. No Parabens. No Fragrance.
No Colorants. No Optical Diffusers.Big thumbs up for that!