Applied each morning after cleansing, was very impressed with the manner in which the product penetrated my skin. It is a very high-quality serum and my skin absorbed it well.
Can't really say it made any real difference in my acne-prone skin. I was also on the look out for whatever benefit an increased "moisture barrier" would have, as the product boasts it would.
Once the sample was exhausted, I wasn't impressed enough to purchase a full size. As the quality was great, I would consider using other products in the line.