The substance may be transparent, but its effect is clear to see: Our Lip Line Definer allows you to draw invisible protective lines around the contours of your lips. This prevents your lipstick or lip gloss from bleeding or smudging. This transparent Lip Line Definer can also be used in combination with our range of coloured Lip Liners: Please apply the Lip Line Definer outside the lip contours and then apply the Lip Liner inside the contour lines.