So here is my evening skin care routine! I am using Tretinoin (Retin-A) for about 1.5 years now and I am starting to see some really good changes- especially on my forehead wrinkles: they are getting smoother and less pronounced. I started using Tretinoin every 2-3 nights and slowly worked my way up. Today I can use it every night. I will shed every couple of weeks, but overall I rarely get irritated anymore- sometimes my neck gets irritated. I will then take a little break. Overall I think it is the most powerful ingredient to actually do something against wrinkles. I am using currently 0.05% and I will probably soon switch to 0.1%. LTKOver40 LTKBeauty