While serums act as supplements to a well-rounded skincare routine, moisturizers are always non-negotiable — even for oily skin. The Daily Beast explains that moisturizers obviously lock hydration into your skin cells while protecting its external barrier. Adding your lotion to cleansed skin is a must for a healthy glow that doesn't look patchy or dry. Dr. Robinson tells Byrdie, "Additionally, [moisturizers] can enhance the functioning of the stratum corneum (the uppermost layer of skin that's made up of fat and oil skin cells) to help retain moisture."

If you have oily skin, find a product that's lightweight and oil-free to reap the hydrating benefits without the breakouts, The Daily Beast suggests. The same goes for your serum — opt for a lighter product to make sure it doesn't lay on your skin and create blemishes. 

While they both serve different purposes, serums and moisturizers can add different benefits to your routine. Byrdie also notes that, for intense skin issues such as spots or fine lines, you'll likely need to combine the beneficial properties of your lotion with a serum for a powerful healing elixir. Think of your serum as your boost of nutrients while your lotion provides the nourishing main course — knowing that you can use one to enhance the healing properties of the other.