Like an artist’s beloved box of colored pencils, lip liners provide precision, pigment, and creative possibility: You can define lip edges, color outside the lines for the illusion of fullness, sketch a bit to subtly contour, or fill in your lips as a primer for lipstick, gloss, or balm.And pulling off such artistry with finesse demands a great formula. The best lip liners glide on smoothly, deliver even, saturated color, and don’t settle into fine lines or disappear with your morning coffee.For this guide, we interviewed makeup artists, consulted a cosmetic chemist and dermatologist, and reviewed a range of formulas to arrive at a group of 33 lip liners for initial consideration. We then sent 18 brand-concealed contenders to 11 panelists, and after two weeks of testing, these three options drew the most praise: a high-impact precision liner, a long-wearing, budge-proof favorite, and a creamy, smoothing standout.