15 Best Hyaluronic Acid Serums to Hydrate All Skin Types. Best Hyaluronic Acid Serum For Sensitive Skin: Ghost Democracy Floodgate Hyaluronic Acid Serum. This Ghost Democracy hyaluronic acid serum is a favorite of Wizemann, who has sensitive skin. "It has 2.1% HA, one of the highest concentrations I've seen, and 4% niacinamide to strengthen the skin's barrier," she says. "I found it to be an excellent base for a moisturizer and noticed my skin looking a little plumper."