Dude I have suffered with this shit since I was 16. I have been on many different diets and have tried many different supplements. The only thing i have gathered from reading plastic surgery messageboards and getting involved in dark circles clubs online, is that the cause of these circles (not the puffyness if you have that) is what that hylexia product you mentioned says the cause is, which is something to do with the blood vessels under the eyes, that hylexia supposedly fixes, however I've read posts from people who have tried it, and many aresaying after 3 weeks they are getting no results.
If you notice, look in the mirror, and kind of like stretch the fat from your cheeks up under your eyes, like youre giving yourself a facelift. You will notice the circles disappear. I firmly believe the only way to get rid of this shit is go see a GOOD plastic surgeon a board certified one, and ask about a lower lid blepharoplasty. Honestly nothing I have excluded from, or included into my diet over many many years has caused these things to go away even the least bit. Save up 5 grand and have the surgery done.