If you haven't had any irritation, I would give it a shot. Why not? Use it every other day, at first, then if you still don't experience any bad side effects, use it nightly.

I am 46 years old as well. You could switch to 1.0 now if you'd like. However, when I tried switching to the 1.0 strength, my skin peeled and peeled. My skin never got used to the extra strength so I have stayed with .5 and it works very well for me.

I am 52.
I have used 0.5 for about 8 months and bought 1.0 . I use both now. I use one, one nite and the other the next nite.
If you find its to strong at first only use it 2 times a week while still using the .5. You will get used to it.
My sking does look good for my age and its because of skinceuticals. I use pigment regulator(twice a week) and phlortein cf everyday.
My spots are faded, but I think its a combo of all products.
Dont forget sunscreen.

The directions are right here on the site. Just type in the product u have.