I've had a very deep single horizontal forehead line since young age. What's the best treatment? (Photo)

I would recommend injecting a thin filler such as belotero or restylane silk into the crease and do it 2-3 times over 1 -2 weeks since one time won't do it justice. Put some in, and see how much stretch it makes then add some more a few days later etc...

I feel the best treatment for these deep forehead lines are to start first with Botox. I typically ask my patients to wait 2 to 4 weeks for the Botox to start to work. I follow that treatment with an HA filler such as Restylane to soften the line further. I find this combination works best to both soften and support those deep lines. I always tell my patients that lines that have been etched in so deeply will never be gone completely, but they can be greatly improved with the above treatment.