According to Kassajikian, they’re safe because the effects are only temporary. However, he does give one warning: “If overused, they can potentially cause dry and chapped lips.” So be sure not to overdo it. Each product was awarded a score from one to five for feel, plumping ability, and hydration, and those with the highest overall scores were featured in this roundup. All assessments were performed in The Lab, our in-house product testing facility in Manhattan. A key ingredient Kassajikian recommends looking out for is hyaluronic acid. As you may already know, hyaluronic acid draws moisture into the skin and holds it there, lending a plumping effect to find lines and wrinkles. It'll have the same effect on your lips—helping them look fuller, plumper, and healthier overall. Our favorite hyaluronic acid-infused option on this list is the PMD Kiss Lip Plumping System.