Not everything works for everyone, and that's because everyone's dark circles/puffiness is caused by something else. I just found out that allergies can cause dark circles! :(
For me, I've been using this stuff:
It takes a long time to work to full potential, but it actually has been working miracles for me. I'd say give it at least 2 months, maybe longer depending on how bad the dark circles are, before you see real results. The small bottle lasts about a month using it twice a day. :3
Before I used that, I used a argan/jojoba oil and body lotion combination under my eyes twice a day to kick start results. It actually worked much faster than this stuff, but I wouldn't use it long term because I'm not sure what it could do to your skin under your eyes or even your eyes themselves.
I used ULTA's beauty smoothie body creme and Proclaim's natural 7 oil argan oil. Mix it in your hand and smooth in under your eyes twice a day. WILL burn like hell if you get it in your eyes. Like I said, I'm not saying if it will or will not damage your eyes any, so use at your own risk. I just mixed those two based on the ingredients listed because I knew they would hydrate without breaking me out. I used for two weeks and my dark circles were about half gone by that point. Freeman's Vita K has gotten them almost completely gone after that in a month and a half.