I purchased this product (full sized) and the companion product after first trying them out in the Help Me kit. I knew I wanted something to smooth up and 'youthen' my skin, so I perused the Birch Box reviews and decided to take the plunge on the Dr. Jart combo kit - Am I ever pleased! I didn't wait to run out of the smaller sizes before ordering the full size products.
The Skin Saver (ceramidin liquid) is the thinnner if the two, more of a serum than a lotion or cream. My skin absorbs it really quickly. I guess you don't HAVE to use the companion product, but I do. They are worth every penny! My skin is smooth, clear and feels (to me) more elastic. Mind you, my skin is nearly 47 years old and I spend quite a bit of time out of doors, so maybe I need a mini facial every day.
Caveat: DO NOT apply and then go out in the sun. Wear sunscreen or a product with SPF - your 'new skin' will be irratated. It only took me once to learn my lesson.