From lotions to oils, serums and creams, many promise the same elusive skin destination- the fountain of youth (or something that looks like it).  And what does it look like?  One thing is certain, youthful skin, at any age, starts with a healthy skin barrier, also known as a lipid barrier.  The lipid barrier is actually made up, in part, of your skin's own natural fats.  This is the same skin barrier that, unfortunately, is also subject to harsh, drying soaps, exfoliation and product overload, as well as weather extremes.  So, how exactly can you maintain or even repair your skin's lipid barrier?  A healthy, aka "youthful," barrier, after all,…