It caused a serious stir and when you snap up The Ordinary Serum Foundation (if you're fast enough!) you'll soon see why. Formulated from a unique combination of colour pigments suspended in the brand proprietary spreadability system this lusciously lightweight serum glides on for a smooth, subtly perfected, semi-matte finish that lasts all day without settling into fine lines. For an ultra-natural result, it available in 21 versatile shades, ranging from very fair to very deep and each classified according to its undertone.shades stand for pink undertones, R for red, N for neutral and Y for yellow, so you can suit your skin tone to a tee. As if you needed further convincing, the formula also offers SPF 15 sun protection without the use of chemical sunscreens.