I have sensitive skin, and most vitamin c serums irritate my skin. The Medik8 C-Tetra Lip Vitamin C Radiance Serum felt very nice and hydrating. I actually did my morning skincare and applied it on top of my moisturizer. It has light oil consistency, and a natural citrus scent (smelled like fresh orange slices). I let my moisturizer dry down a bit, and applied this on top. I don't know if it plays well under makeup. I think it would work well in a nighttime skincare routine as well.