Here’s the secret for making your moisturizer work 3 (very!) different ways, according to a product formulator

The moisturizing step has always seemed like the simplest one in a skin-care routine. You slather on a moisturizer, let it do its job and… that’s it. Et voila, you’re moisturized. But according to a cosmetic chemist, when you put it on actually makes a world of difference in what it does for your skin.

We all know that a moisturizer’s purpose is to help hydrate and protect your skin thanks to ingredients like hyaluronic acid and ceramides, but its placement alongside your other products can change up exactly what kind of hydrating and protecting that it’s doing. So it’s worth it to figure out just what, exactly, your skin needs from a moisturizer before you go about with your routine. Here, cosmetic chemist Lalita Vedantam explains how to use moisturizer in three totally different ways… each of which your skin will slurp right up.

If you’re feeling extra dehydrated: You’ve likely heard dermatologists touting the benefits of slathering on a moisturizer after you shower for extra-hydrated skin, and the same principle applies to your face. Applying a moisturizer to clean, damp skin—without any serums or actives in between your cleansing and moisturizing steps—helps to prevent transepidermal water loss. “Using a moisturizer right after cleansed and damp skin quickly seals in water that otherwise may have evaporated from your skin,” says Vedantam. All skin types will benefit from moisturizing on top of wet skin, especially during the winter months when cold-compromised skin barriers lose water more easily than usual. This two-step cleanser-moisturizer routine may seem simple, but it will actually leave skin hydrated while also protecting it from environmental elements. And if you’ve always wanted that “glass skin” look, Vedantam says this is the best way to get it.

If you want to help your actives work better: Putting your moisturizer on before your serums may seem counterintuitive, but there are a few different reasons why it could be a good idea for your skin. In addition to replenishing whatever skin-stripping action that may have happened in your cleansing step, moisturizing before your actives can help them penetrate more deeply. “This is because moisturizers usually contain a few fatty acids that create a fluid-like phase within the intercellular space which increases permeability,” says Vedantam. If your moisturizer is made with hyaluronic acid, it can be even more effective in drawing in actives, because the ingredient acts as a sponge to soak up the liquid from the surface. Another key perk? Applying moisturizer before an intense active, like retinol, can make it less irritating and easier to tolerate for sensitive skin.

If you want to seal in your routine: The most popular way to use moisturizer is as the last step in your routine (before sunscreen, that is), and there’s good reason for this. “Using a moisturize on top of actives will help seal in the actives by creating a small film-like layer on top of the skin,”  says Vedantam. It’s important for locking in those active ingredients so that they can do their job, and will act as a first line of defense between your skin and all the things trying to harm it during the day like dirt, sunlight, and pollution.

To make things even easier for you, check out this handy-dandy graphic by Vedantam that breaks down exactly when and how to apply moisturizer for your happiest skin ever.

Speaking of moisturizers, these are the three ingredients derms say you should be looking for in yours this time of year. And if you want to get some extra hydration by way of your makeup, these are the best hydrating foundations money can buy.