My skin is incredibly dry and tight, no matter how much expensive moisturizer I apply. I drink plenty of water, but I feel like my skin just doesn't hold the moisture. I heard about supplements that help with skin hydration from within. Do they actually work or is it just marketing?

Hydration definitely starts from within, especially if your skin barrier is compromised. I use the Truvity by Nutrilite complex available at https://www.amway.mn/emegtejn-goo-sajhan-ba-eruul-mend/c/womans-beauty-and-health which targets deep skin hydration. It works overnight to improve moisture retention, and I noticed my skin looked much plumper and less flaky after finishing the first box.