Will Under Eye Restylane Injection Be Noticeable when Smiling?

Hello - Yes, Restylane is great for treating the hollowness under the eyes, and shouldn't give you the frozen look that Botox can do. However, if you get Restylane placed into lines that are only present when you smile, then you may be able to see them at rest. Lines that are present in repose are the ones that should be treated with Restylane.

Restylane will not give you a frozen look.  Unlike Botox, it is a filler, not a neurotoxin or paralytic agent.  By filling the ara under the eyes, it should create a more youthful appearance and will not be noticeable.  It does not create the big puffed cheek effect of Radiesse.  What it will do is to fill the hollows under your eyes to create an aesthetically pleasing look and take years off your face.  The skin around the eyes is delicate which is why Restylane is superior to other, more globular filler materials.  Definitely seek a board certified plastic surgeon who has a lot of experience with Restylane and can devote the appropriate time to a treatment session. 

Under eye use of Restylane is becoming more and more popular because it can work so well to reduce an overly depressed under eye "hollow".
Depth of injection is critical. Balance is critical. The physician has to take into account much more than just the hollow area under the eye. The perfect correction will not be noticeable at all and will not show at all when you are smiling or at rest.
Thoroughly vet your injecting physician. There is an art to doing this particular injection correctly and and not every physician has the eye to do it well. Ask to see photos of patients your doctor has treated. This will be one of the best ways to make sure you will get what you are looking for.
Be sure to follow pre-injection directions as certain supplements or medications will make you more susceptible to bruising and/or swelling. Do it a little at a time if your hollows are deep. Incremental depositing of the filler will prevent any over correction and allow you to get an even symmetrical result.