The word “hybrid” might be the word of 2020.

If you know a student or a teacher, you’ve heard all about hybrid learning, which means a mix of virtual and in-person classes. Hybrid products are just like that — combining two things into one for hopefully optimal results.

This year, we saw a few hybrid skin care products, mostly serum hybrids. I long promised an explanation on what a serum was and the order of skin care products to use, so this is the perfect time to do it.

First, a serum is a skin care product that contains a high concentration of ingredients and is intended to deliver a direct shot of these ingredients into the skin. The consistency of a serum is almost syrupy, somewhere between a liquid and a cream. It contains smaller molecules than the latter, so serums can penetrate deeper into the skin to yield better, faster and stronger results. Thanks to this, a serum is a good idea if you’re looking to target specific skin concerns. For instance, a retinol cream is good to help soften and prevent lines, wrinkles and sagging, but a retinol serum is even better.

Next up, the elusive order. You have no idea how many messages, comments and emails I get about the order of skin care products. Like most skin care concerns, there are no hard-and-fast rules. It depends on your skin, the product and its ingredients. However, the general rule is that, after cleansing, products be applied from thinnest to thickest consistency, which means serums should be applied to the skin after cleansing and toning and before moisturizing. Serums can contain moisturizing ingredients such as hyaluronic acid, but serums need a thicker barrier on top to keep all of its goodness in.

This means: toner, eye cream, essence, serum, moisturizer and then oil. In the morning, sunscreen should be your final step.

So where do serum hybrids fit in? It depends on what the serum is combined with.

First, let’s talk toner-serum hybrids. If you remember the column on toners a few weeks ago, a good toner should serve a few basic functions to facilitate the rest of your skin care routine. Toners should help balance pH for optimum oil levels; toners should hydrate skin or help to exfoliate, depending on its ingredients; and toners should help the following skin care products penetrate deeper. Mix these toners with serums, and you get the best of both worlds.

For instance, something like Fenty Skin Fat Water is a super-hydrating mix of ingredients to plump and brighten skin, such as skin care juggernaut niacinamide, Barbados cherry aka acerola (a form of vitamin C), antioxidant-rich green tea and more. On the flip side, Bliss Clear Genius Clarifying Toner + Serum is made with salicylic acid, a beta hydroxy acid, as well as witch hazel and zinc PCA, which help to gently exfoliate, minimize the appearance of pores, and smooth and clear skin.

Next up are oil-serum hybrids, which in some cases, have been around long before we were calling things “hybrid” products. An oil is meant to help lock in moisture and typically consists of a blend of oils, each with their own skin care benefits. Serum-oil hybrids will deliver those active ingredients into your skin and add a layer of extra moisture and barrier protection. Oils are typically reserved for the end of your skin care routine since oil can penetrate moisturizer. However, ingredients are king. If your serum oil is chock-full of good ingredients, like cult-favorite Kiehl’s Midnight Recovery Concentrate, you can absolutely use it before moisturizer. Don’t forget to include the price in that equation as well. Vintner’s Daughter Active Botanical Serum is extremely pricey, but according to every beauty editor, absolutely worth it. At $65 for 5 milliliters, you better put that right down on your skin like it was a serum and soak up all of its botanical goodness.

If it’s something like Glossier FutureDew, which is to be used as a super-hydrator to give your skin a dewy finish, use it after your moisturizer.

The best part about these hybrid products is that they save time. You’re absolutely allowed to use additional skin care products, but these hybrids can hit two steps at once to streamline your routine and help de-clutter your shelves. I am a total skin care fanatic and love to line up all of my pretty bottles and apply multiple products to my skin, but sometimes it’s about using optimal products to get us out the door. Thanks to these multi-use products, your skin will still be glowy and fresh.