I bought this serum because I really like fermenet stuff. This serum is very light and has a yellow color. You have to apply it with a cotton pad (which is sad, because much of the product is then soaked up). However it does seem to be a good serum that calms skin. When you apply it on your skin, it pricles a bit and I like that feeling. It seems to be doing something to my skin :) Unfortunatelly it didn't do yet much for my acne prone skin. But this could also be because I haven't used it so long yet. I do imagine that it shows effect after 2-3 month...