Serum or Moisturizer: Do You Really Need Both?

Yes, in most routines, you need both. Serum and moisturizer may both hydrate the skin, but they serve different purposes. A serum delivers targeted ingredients in a lightweight formula. Moisturizer helps support the skin barrier, soften the skin, and reduce water loss.

Think of it simply: serum targets. Moisturizer supports. SPF protects.

Used together, they create a routine that helps skin stay hydrated, comfortable, resilient, and beautifully balanced.

The confusion makes sense. If your serum contains hyaluronic acid and your moisturizer contains hydrating ingredients too, the two steps can seem redundant. They aren't. Understanding what each product is designed to do can help you build a better routine without simply adding more products.

What Does Serum Actually Do?

Serum is where your skincare routine can become more specific.

Serums are generally lightweight formulas designed to deliver targeted ingredients based on what your skin needs, whether that's hydration, antioxidants, brightness, texture support, or renewal.

A hydrating serum, for example, can help replenish moisture. An antioxidant serum can help defend against environmental stressors. Other serums may be formulated to address the appearance of uneven tone, fine lines, or changes in texture.

When you apply a serum like The Daily Serum, the lightweight texture absorbs easily and layers beautifully beneath moisturizer. The goal isn't to make your routine heavier. It's to give your skin targeted support before you seal everything in with the next step.

This is also why choosing the right serum matters more than simply using more of them. Your skin doesn't need every ingredient. It needs the right ingredients for what it is doing now.

What Does Moisturizer Actually Do?

Moisturizer plays a different role.

While serum can deliver targeted ingredients, moisturizer helps support the skin's protective barrier and reduce transepidermal water loss, the water that naturally escapes from the skin throughout the day.

A moisturizer like Daily Hydrating Cream provides hydration while helping skin feel soft, smooth, and comfortable. Applied after serum, it helps create the environment skin needs to maintain hydration.

Moisturizers can also contain their own beneficial ingredients, including humectants, emollients, antioxidants, peptides, or barrier-supporting lipids depending on the formula.

The important distinction isn't that serum works while moisturizer simply sits on top. Both can contribute to healthy-looking skin. They are simply formulated to do different jobs.

Serum targets. Moisturizer supports.

Why the Skin Barrier Matters

Hydration isn't only about adding water. It's also about helping skin hold onto it.

Your skin barrier is the outermost layer of the skin and plays an essential role in keeping moisture in while helping protect skin from the outside environment.

When that barrier is functioning well, skin tends to feel smoother, softer, and more comfortable. When it becomes compromised, skin may feel dry, tight, sensitive, or irritated, even if you're already using hydrating products.

That's where the relationship between serum and moisturizer becomes important. A hydrating serum can help increase hydration, while moisturizer supports the barrier that helps maintain it.

Sometimes the answer to dehydrated-looking skin isn't another active ingredient. It's helping the skin make better use of the hydration you're already giving it.

Do You Use Moisturizer After Hyaluronic Acid?

In most routines, yes.

Hyaluronic acid is a humectant, meaning it helps attract and retain water. That's one reason it appears in so many hydrating skincare formulas.

If you're using a hyaluronic acid serum, applying moisturizer afterward can help support the skin barrier and reduce water loss, allowing skin to remain hydrated and comfortable for longer.

You can also apply a hydrating serum to slightly damp skin. This can be especially helpful when using humectant-rich formulas. Follow with moisturizer and, during the day, sunscreen.

If you want to understand the ingredient more deeply, read why hyaluronic acid serums work better than you think.

Do You Really Need More Than One Serum?

Not necessarily.

More skincare doesn't automatically mean better skin.

Start with the concern you most want to address, then add another serum only when it has a clear purpose in your routine. Layering too many formulas can duplicate ingredients, increase the possibility of irritation, or cause products to pill beneath moisturizer and sunscreen.

You may also find that different serums make sense at different times of day.

For example, Rescue Vitamin C + Squalane Serum can be incorporated into a routine focused on antioxidant support and brightness, while Supernova Retinol Serum can be used as part of an evening routine focused on renewal.

For skin that could benefit from antioxidant and nourishing support, Rejuvenating Antioxidant Oil Serum offers another option and can be incorporated according to how your skin responds to richer formulas.

The goal isn't to collect serums. It's to choose intentionally.

How Do You Know What Your Skin Needs?

Your skin changes.

Weather changes it. Stress can change it. Travel, hormones, age, sleep, treatments, and your environment can all influence how your skin looks and feels.

Dryness, dehydration, dullness, and a compromised skin barrier can also look similar even though they aren't necessarily the same concern.

The serum that works beautifully for you in summer may not be what your skin wants in January. Your moisturizer may need to change too.

That's why Joanna's approach has never been about building the longest possible skincare routine. It's about paying attention to your skin and adjusting your routine as your skin changes.

Consistency matters. Complexity doesn't.

You can see that philosophy in Joanna's four-step daily skincare routine: cleanser, serum, moisturizer, and sunscreen, with the products within those categories adjusted according to what her skin needs.

What Is the Correct Order for Serum and Moisturizer?

A useful rule is to move from lighter formulas to richer ones.

Start with freshly cleansed skin. Apply your serum according to its directions, then follow with moisturizer. You don't need to wait until every trace of serum has disappeared before applying your next step. Give the formula a moment to settle, then continue.

For most morning routines, the order is:

Cleanser → Serum → Moisturizer → SPF

For most evening routines:

Cleanser → Serum → Moisturizer

If you're using an oil serum, placement can depend on the formulation. Some oil-based serums layer beautifully beneath cream, while richer facial oils may work better as a final step. Follow the directions for the specific product and pay attention to how the formulas layer on your skin.

What Happens If You Skip Serum?

You can absolutely have a skincare routine without serum.

A well-formulated moisturizer can hydrate and support the skin barrier on its own. What you may miss are the more targeted ingredients a serum can provide for specific concerns.

If your routine is intentionally minimal and your skin feels healthy and comfortable, you don't need to add a serum simply because you think you're supposed to.

But if you're trying to address a particular concern, such as dehydration, dullness, uneven-looking tone, or visible signs of aging, a thoughtfully chosen serum can make your routine more targeted.

What Happens If You Skip Moisturizer?

This depends on your skin type, environment, and the other products in your routine.

For many people, particularly those with dry or dehydrated skin, serum alone may not provide enough barrier support to keep skin feeling comfortable throughout the day.

A moisturizer adds emollient and barrier-supporting ingredients that many lightweight serums aren't designed to provide.

If your skin routinely feels tight shortly after completing your skincare routine, that's useful information. You may need more barrier support rather than another active ingredient.

When Should You Adjust Your Serum and Moisturizer?

There isn't one combination that works perfectly every day of the year.

During warm, humid weather, you may prefer a lightweight serum followed by a lighter moisturizer. In colder or drier conditions, skin may feel better with a richer moisturizer that provides additional barrier support.

If your skin feels dry or tight even when you're using both serum and moisturizer, consider whether your routine has become too aggressive. Over-exfoliation, frequent use of strong actives, environmental changes, and cleansing habits can all affect how comfortable your skin feels.

You can also introduce additional hydration periodically with a treatment such as the Twilight Face Mask when your skin needs extra care.

If your skin feels oily or congested, that doesn't necessarily mean you should eliminate hydration. A lighter serum and moisturizer may simply be more appropriate than rich, highly occlusive formulas.

What About Serum and Moisturizer After a Professional Treatment?

After professional treatments, the rules can change temporarily.

Procedures such as RF microneedling can require specific post-treatment skincare. Rather than automatically adding extra serum or applying your usual active ingredients, follow the instructions provided by your medical provider or esthetician.

During recovery, the emphasis may shift toward gentle cleansing, hydration, barrier support, and sun protection before certain active ingredients are gradually reintroduced.

Your regular routine can be powerful precisely because it is consistent. After a professional treatment, however, knowing when to simplify it is just as important.

So, Do You Need Both Serum and Moisturizer?

For most people, using both makes sense because they serve different purposes.

Serum allows you to target what your skin needs. Moisturizer helps support hydration and the skin barrier. During the day, sunscreen completes the routine by helping protect skin from UV exposure.

Serum targets.
Moisturizer supports.
SPF protects.

Beautiful skin rarely comes from adding more and more products. It comes from understanding what each step is supposed to do, choosing formulas that make sense for your skin, and using them consistently.

Consistency matters. Complexity doesn't.

And if you're not sure what your skin needs right now, that's exactly where professional guidance can help. Visit Joanna Vargas in New York, Los Angeles, or Brooklyn, or take the Skin Code Quiz to discover the serum and moisturizer combination that makes sense for your skin right now.

Frequently asked questions

Can I use just serum without moisturizer if my skin is oily?

If your skin is oily, you may still benefit from moisturizer, but the texture matters. Look for a lightweight moisturizer that hydrates without feeling heavy. Oily skin can still become dehydrated, and a serum alone may not provide the same barrier support as a moisturizer. If your skin feels comfortable with a very lightweight routine, pay attention to what it is telling you rather than adding products simply because you think you should.

Should I wait between applying serum and moisturizer?

You don't need to wait a specific amount of time between serum and moisturizer. Give your serum a moment to settle, then apply moisturizer. If you're using a hydrating serum, it can often be applied to slightly damp skin before following with moisturizer. The goal is comfortable, even layering, not waiting for each product to dry completely.

Can I layer two serums before moisturizer?

Yes, you can layer two serums if the formulas and active ingredients are compatible, but more isn't necessarily better. Apply lighter formulas before richer ones and give each serum a clear purpose in your routine. Too many active ingredients can increase the risk of irritation or cause products to pill beneath moisturizer and sunscreen. In many cases, choosing one targeted serum is all your skin needs.

Does moisturizer block serum from absorbing?

No. Applying moisturizer after serum doesn't prevent the serum from doing its job. Serums are generally formulated as lightweight treatments, while moisturizers help hydrate, soften, and support the skin barrier. Applying lighter formulas before richer ones is a useful layering principle because it helps products spread evenly and comfortably. Think of the two steps as complementary: serum targets; moisturizer supports.

Which goes first, serum or moisturizer?

Serum usually goes before moisturizer. A simple rule is to layer from lighter formulas to richer ones: cleanse, apply serum, follow with moisturizer, and finish with SPF in the morning. At night, the basic order is cleanser, serum, then moisturizer. Always follow the directions for individual treatment products when they differ.