I have been using Mario Badescu products for years, but just tried this Herbal Hydrating Serum.  Other reviewers have mentioned that this serum is thicker than most serums.  Though the Herbal Hydrating Serum feels thick it doesn't feel greasy or oily.  It let my skin feeling a little tacky, but not uncomfortable.  I've been using this serum in NYC in August when it is hot and humid, I expect that this will work really well while traveling and in colder, drier weather.