Good skin health requires a balance of hydration / moisture in the form of Hyaluronic acid and a healthy lipid barrier to trap water and moisture in. As we age, Hyaluronic acid levels start to fall as so does a thinning of our lipid barrier. Serum TEWL is a great face oil that is non-oily but intensely comforting. Importantly, it replenishes lipid depletion whilst eliminating that skin tightness that accompanies dehydrated skin. When your HA serums or moisturizers don't seem to work anymore, it may be because whilst you are replenishing the loss HA, you are not doing anything to restore the weak lipid barrier and hence, any water from the dermis is just evaporated at the skin's surface. The other one to consider is Skinceuticals's Triple Lipid Restore. Its texture is more a cream base but not as hydrating as Serum TEWL.