From thinnest to thickest , I also love to mix different serum's together as well as my creams. I do this by putting a small amount of each( serum or cream )then rub my hands together to combine before applying to my face and neck. For example.....my serum's , I'll put a small amount of snail serum , vitamin C serum and a hyaluronic acid serum in my palms and rub them together then apply. I do this twice a day and each time I use different products. I always check my ingredients so I don't accidentally mix the wrong Actives together , it works great and I actually have fun experimenting with my skincare. Of course everyone's skin is different and reacts differently to certain products. My skin isn't sensitive , it's mature , oily with moderate breakouts (hormonal acne)