I use this in the daytime under my sunscreen and it works great. Doesn't irritate my skin at all. I will continue to purchase and use this.
I wanted to replace a product that I relied on for years, but is discontinued. This seemed to be the closest match. It is a bit stronger on my skin, so I use it less often, but it is a very good product to add to a skincare regimen. If you are not sure of what level/strength to get, it is likely better to choose the lower level.
I have been using this product for years. I bought two of my daughters this product for Christmas. Oldest daughter has been using level one and loves it.