Those sunken areas under the eyes that leave us looking weathered? “Low estrogen–triggered laxity in the skin causes the fat pads that once sat there to droop, leaving a hollowed-out spot behind,” says dermatologist Tsippora Shainhouse, M.D. Hyaluronic acid to the rescue! It can hold up to 1,000 times its weight in water, bringing moisture into the skin to help fill in deflated areas. Plus, hyaluronic acid has been shown to boost skin elasticity by 55 percent in eight weeks. TO DO: Massage a hyaluronic acid–infused eye cream (we like Neutrogena Hydro Boost Eye Gel-Cream, Walmart.com) onto the skin around the eyes twice a day for results in 30 days.