The difference between face serum and moisturizer

You may have heard that facial serums and moisturizers are key ingredients of any skincare routine, but what do they actually do? And which one should you apply first? Does it matter? Read on as we answer these important questions. 

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Face serums generally address specific skin concerns, such as aging changes, hyperpigmentation, or sun damage. They’re made with a base of oil, gel, or water and often come in a bottle with a dropper so that you can deliver a more targeted dose.

Depending on the formulation, facial serums may improve your skin’s overall appearance by (McCall-Perez, 2011):

• Reducing fine lines and wrinkles

• Brightening and smoothening skin

• Evening out skin tone

• Boosting elasticity

• Minimizing pores 

The ingredients in a serum depend on the product’s goal. For example, anti-aging serums may contain ingredients such as apple cell extract, urea, or vitamin C (Sanz, 2016). Vitamin C can also help with skin brightening and hyperpigmentation (Al-Niaimi, 2017). 

Hyaluronic acid is another common ingredient in serums. Its ability to attract moisture may help with reducing fine lines and plumping the skin. Other common serum ingredients include peptides, plant extracts, and vitamins (Juncan, 2021).

Face serums are best applied when your face is clean and damp, like after you’ve washed your face or taken a shower (Werschler, 2011; Purnamawati, 2017). Given their potency, some serums may cause irritation for people who are sensitive to the active ingredients, so always review the ingredient list and start with a small spot test first.

While face serums can address a number of skin concerns, moisturizers share one common goal: moisturization (Sethi, 2016). 

Hydrated skin looks healthier, plumper, and younger (Purnamawati, 2017). It also feels smoother. That’s because the extra hydration plumps out your skin, reducing the appearance of fine lines and wrinkles, and making your skin more soft and pliable for hours after application (Sethi, 2016). 

Moisturizers may contain several ingredients that help with hydration, such as (Sethi, 2016; Purnamawati, 2017; Harwood, 2021):

• Water: Surprise, surprise: water helps hydrate your skin, so it’s a main ingredient in many moisturizers. The top layer of your skin—the stratum corneum—contains dead skin cells that absorb water. To avoid dryness, the stratum corneum should contain at least 10% water.

• Occlusives: Occlusives are oily substances such as petrolatum, beeswax, lanolin, silicones, and mineral oil. While the stratum corneum wants to absorb water, it needs a little help holding it. That’s where occlusives come in. They help trap moisture in your skin and prevent transepidermal water loss (when water evaporates from the surface of your skin into the air around you).

• Humectants: Humectants like glycerin, propylene glycol, honey, panthenol sorbitol, glycolic acid, and hyaluronic acid attract more water to your stratum corneum. They can actually attract water from both sides—humid outside air, as well as the deeper skin layers—to further hydrate the stratum corneum.

• Emollients: Emollients round out the list of moisturizer ingredients. These include squalenes and fatty acids like palm oil, coconut oil, or jojoba oil that help bolster your skin’s barrier function and help your skin feel and look better. Emollients often give the moisturizer its fragrance as well.

In addition to their main benefit of hydration, moisturizers may contain other ingredients that address other skin needs, such as aloe for inflammation, retinol for anti-aging, or zinc oxide for sunscreen (Purnamawati, 2017; Sethi, 2016).

Like face serums, moisturizers are best used when your face is clean and damp, such as after you’ve washed your face (Purnamawati, 2017). You can apply them after your serum (more on that later) (Werschler, 2011). 

Serums and moisturizers are both facial skincare products, and they’re best applied when the face is clean and damp (Sethi, 2016). Where they differ are in their formulations and the skin concerns they target. 

Moisturizers are primarily designed to hydrate the skin, while serums can target various skin concerns, from aging to acne. Serums are also highly potent and concentrated, with just a few drops needed for formulation. Moisturizers, on the other hand, contain a lot of water along with other ingredients, and a more liberal application is recommended (AAD, n.d.). 

Finally, moisturizers have a thicker formulation in order to create that water barrier and prevent moisture loss (Harwood, 2021). 

Depending on your skincare goals, you may want to include both serum and moisturizer in your daily routine. 

One small two-week study found that women who applied hydrating serum in addition to moisturizer, as opposed to moisturizer alone, had less dryness and softer skin (Werschler, 2011). And many of the studies touting the benefits of serum also had the participants apply moisturizer (McCall-Perez, 2011; Werschler, 2011). 

However, that does not mean that serum can’t sufficiently moisturize your skin. Ultimately, it may depend on your skin type, skin concern, and the serum ingredients. For example, a study of women with sun damage suggests that a serum containing l-ascorbic acid, hyaluronic acid, and other ingredients may improve skin moisture, with participants reporting brighter skin, more hydration, and fewer wrinkles (Garre, 2018). 

Another study found that serums containing hyaluronic acid may benefit the skin’s natural ability to retain moisture. After four weeks of using the serum, participants experienced an increase in their natural levels of hyaluronic acid, along with a boost in collagen, which led to improved skin quality and hydration (Raab, 2017).

The bottom line: Because serums and moisturizers target different skincare concerns, consider using both, not one or the other. If you’re choosing only one, go with moisturizer—but know that a serum can help you better address specific skincare concerns. 

Yes, you can use serum and moisturizer together. The general rule of thumb for skincare products is to go from thin to thick. Start with your thinnest formulas and finish with thicker ones. In other words, you want to apply serum before moisturizer. 

Here’s how to layer serum and moisturizer (McCall-Perez, 2011; AAD, n.d.):

• Wash and clean your face, then pat your skin dry. 

• Apply the serum to your face and neck, patting or rubbing it into the skin.

• Wait about a minute to allow your skin to absorb the serum.

• Then, apply your moisturizer (you can apply it up to three times daily, depending on how dry your skin is) (Sethi, 2016). 

• Finally, if your moisturizer doesn’t have SPF, apply sunscreen on top.

Be sure to always follow the instructions on the product label, and check the product’s list of ingredients. Some moisturizers and serums contain active ingredients that don’t mix well together. And there are a lot of products out there, some of which may be more or less suited to helping you with your skincare concerns (Draelos, 2013). 

If you have a skin condition or specific concern you’d like addressed or want to ensure that the ingredients in your serum and moisturizer pair well together, reach out to a dermatologist.

It’s totally up to you. A routine that includes cleansing and moisturizing is a good and effective baseline that drives real benefits. 

However, some research suggests that a multi-step routine (including cleanser, toner, eye cream, serum, and day and night moisturizers) may provide more noticeable benefits when it comes to deep hydration, skin smoothness, pore appearance, and the depth of crow’s feet wrinkles. Plus, a daily routine makes it easier to keep it a habit (Messaraa, 2020).

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

May 20, 2022

Written by

Amelia Willson

Fact checked by

Chimene Richa, MD

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About the medical reviewer

Chimene Richa, MD

Dr. Richa is a board-certified Ophthalmologist and medical writer for Ro.