I have deep,dark circles under my eyes and have used undereye cover cream for more years than I'd like to count. One day, I realized the cover cream wasn't working. I would apply and reapply several times a day to no avail.
Received Restylane injections under my eyes and was amazed! No more dark circles. The treatment lasted about 12 months and I went and did it again. I still use a tad of cover cream in the morning, but don't worry about it (or obsess!) for the rest of the day.
I highly recommend Restylane. Make sure you go to someone who is well recommended. I had my injections by a plastic surgeon. Also, make sure you stop taking ibuprofen and/or aspirin two weeks before your injections to prevent bleeding. There is no down time, although you may bruise. I had a small black-eye type bruise under one eye the first time, and the second time a slightly larger bruise under the other eye (I wasn't reminded and had forgotten about the ibuprofen. The doctor used a lot of pressure to stop the bleeding, thus the bruising.)
The small amount of pain (during the injections only) is more than worth the excellent results. I will do it again, when this batch wears off in the next month or two.