Every Single E.L.F. Beauty Product in the New "Mean Girls" Movie, Ranked

E.L.F. Skin Youth Boosting Advanced Retinol Serum ($22)

Spot it: In Regina's room

Finding a decent retinol serum can be confusing, but trust me when I say that this one from E.L.F. is good — really good. Instead of retinol (the most commonly used type of retinoid and the one you've probably heard of before), it uses a mix of retinal and Granactive retinoid, which work much faster than retinol and are far less likely to irritate your skin. These ingredients are normally only used by more expensive skin-care brands, making this a total bargain. The only catch is the yellow tinge, which is down to the color of the raw ingredients, but the silky texture and fine-line-busting results make it worth marking your pillowcase a little (don't worry — it washes out easy).