Face serums are now a familiar part of many skincare routines, but what does face serum do, and do you actually need one?
A face serum is usually a lightweight leave-on product formulated around a particular skincare purpose. Depending on the formula, a serum may help maintain hydration, improve how smooth or comfortable the skin feels, or support a more balanced-looking complexion.
Serum is not automatically better than moisturiser, and it does not necessarily replace one. The two formats often have different roles: a hydration-focused serum provides a lightweight layer of humectant ingredients, while a moisturiser can add emollient and moisture-retaining components.
This guide explains what face serum is, how it works as a cosmetic skincare step, which ingredients to look for and how to use serum without making your routine unnecessarily complicated.
What Does Face Serum Do? The Short Answer
A face serum provides a lightweight way to apply selected cosmetic ingredients before moisturiser. What it does depends on its formulation: a hydrating serum may help attract and retain moisture at the skin's surface, while other serums may be formulated to support the appearance of tone, texture or radiance.
Serum is a product format, not a guarantee of a particular result. The complete formula, how it is used and whether it suits your skin matter more than the word “serum” on the label.
What Is a Face Serum?
A face serum is a topical skincare product that typically has a fluid, gel-like or lightweight lotion texture. Serums are usually applied after cleansing and before moisturiser.
Rather than describing one specific type of formula, the word “serum” describes a product format. Different serums can be designed around very different purposes and ingredients. There is no universal concentration, texture or performance standard that applies to every product called a serum.
Common examples include:
- hydrating serums containing humectants such as hyaluronic acid, glycerin or panthenol
- antioxidant serums formulated to support the appearance of skin exposed to everyday environmental stress
- brightening serums designed to support a more even-looking or radiant complexion
- exfoliating or active serums that require more careful introduction and use
The finished formulation matters more than the word “serum” on the label. Texture, ingredient combination, concentration, supporting ingredients, packaging and how the product fits with the rest of your routine all influence the experience of using it.
What Does Face Serum Do for Your Skin?
The answer depends on the formula. A serum does not have one universal benefit, and not every serum suits every person.
A hydration-focused face serum may help:
- attract and retain moisture at the skin’s surface
- support softer, smoother-feeling skin
- reduce the feeling of dryness or tightness
- provide lightweight hydration beneath moisturiser
- support overall skin comfort and a hydrated-looking appearance
Some serums are designed for other cosmetic goals, such as improving the look of dullness, uneven tone or texture. Those effects depend on the ingredients, concentrations and formulation used.
It is better to choose a serum for a clearly defined need than to add one simply because serums are popular. If your main concern is dehydration or tight-feeling skin, a straightforward hydrating serum may be more appropriate than a formula containing several strong actives.
Face Serum Benefits: What Can a Hydrating Serum Offer?
Lightweight hydration
Hydrating serums often use humectants—ingredients that help attract and retain water. Their fluid textures can provide hydration without the richer feel associated with some creams.
A comfortable first leave-on layer
Because serums are generally lightweight, they can sit comfortably underneath moisturiser, sunscreen and makeup when the products are compatible and appropriate amounts are used.
Flexible use across different skin types
A lightweight serum may suit dry, dehydrated, normal or combination skin, depending on the complete formulation. Someone with combination skin may appreciate hydration that does not feel excessively rich across the oilier areas of the face.
Targeted ingredient selection
A serum can provide a convenient way to incorporate ingredients such as hyaluronic acid or panthenol into a routine. However, more ingredients do not automatically produce a better result. A focused, well-tolerated formula can be easier to use consistently than a complicated mixture of actives.
Serum vs Moisturiser: What Is the Difference?
A face serum is usually the lighter first leave-on layer; moisturiser follows to help maintain hydration.
Serum and moisturiser are not interchangeable terms.
| Face serum | Moisturiser |
|---|---|
| Usually fluid, gel-like or lightweight | Usually a lotion, gel-cream or cream |
| Often focuses on a particular cosmetic purpose | Commonly combines hydration, softening and moisture-retaining functions |
| Frequently contains humectants or other targeted ingredients | May combine humectants, emollients and occlusive ingredients |
| Usually applied before moisturiser | Usually applied after serum |
A hydrating serum may help attract and retain moisture, while a moisturiser can provide the next layer of emollient and moisture-retaining support.
This is why many routines use both:
Serum → Moisturiser
For a detailed explanation of application order, read How to Layer Skincare: The Correct Skincare Routine Order. To understand moisturiser’s role specifically, see What Does Moisturiser Do?.
Which Ingredients Should You Look for in a Hydrating Serum?
Hydration-focused serums commonly use humectants such as hyaluronic acid and Pro-Vitamin B5.
There is no single ingredient that every face serum needs. For hydration-focused formulas, several well-recognised humectants may be useful.
Hyaluronic acid
Hyaluronic acid is widely used in topical skincare as a humectant. It helps attract and retain moisture and can contribute to smoother, more hydrated-looking skin.
You may see different forms listed on an ingredient label, including sodium hyaluronate, hydrolysed sodium hyaluronate, sodium acetylated hyaluronate or sodium hyaluronate crosspolymer. A product containing several forms is sometimes described as a multi-weight hyaluronic acid formulation.
Different forms do not mean a serum will automatically suit everyone. The complete formulation and how it feels on your skin remain important.
Panthenol (Pro-Vitamin B5)
Panthenol is a cosmetic humectant and skin-conditioning ingredient. In a hydrating formulation, it can help maintain moisture and support soft, comfortable-feeling skin.
Glycerin
Glycerin is a widely used humectant found in serums, moisturisers and many other skincare products. It helps attract and retain moisture within the outermost layers of the skin.
Saccharide isomerate
Saccharide isomerate is a carbohydrate-derived humectant used in cosmetic formulations to support moisture retention and a hydrated skin feel.
Fragrance-free formulation
If your skin is sensitive-feeling or you prefer a restrained routine, you may choose a serum without added fragrance. Fragrance-free does not guarantee that a product will suit every person, so patch testing and gradual introduction remain sensible.
How Do You Choose a Face Serum?
Start with the concern you want the product to address.
For dehydrated or tight-feeling skin
Look for a hydration-focused formula containing humectants such as hyaluronic acid, glycerin, panthenol or saccharide isomerate. Follow with moisturiser to complete the moisturising step.
For sensitive-feeling skin
Consider a relatively simple, fragrance-free formula and avoid introducing several new active products simultaneously. “Sensitive skin” is broad, and individual responses can vary, so a patch test is useful before full facial application.
For combination skin
A lightweight hydrating serum can provide a flexible first layer. The amount of moisturiser used afterwards can then be adjusted according to how different areas of the face feel.
When using strong active products
If your routine already contains retinoids, exfoliating acids or other potentially irritating products, introduce additional products carefully. Follow the individual product directions and seek professional advice if you have persistent irritation or a diagnosed skin condition.
How and When Should You Apply Face Serum?
Apply a lightweight face serum after cleansing and before moisturiser; during the day, finish with sunscreen.
For most lightweight serums, the usual order is:
Morning
Cleanse → Serum → Moisturiser → Sunscreen
Evening
Cleanse → Serum → Moisturiser
To apply a face serum:
- Begin with clean skin.
- Apply the amount recommended on the product label.
- Spread or gently press the serum evenly over the skin.
- Allow it to settle comfortably.
- Follow with moisturiser.
- During the day, finish with an appropriate sunscreen according to its label directions.
Using more serum does not necessarily improve the result. Excess product can feel sticky or contribute to pilling when additional products are layered over it.
Can You Use Face Serum and Moisturiser Together?
Yes. A hydrating serum and moisturiser can perform complementary cosmetic functions.
The serum provides the lighter hydration-focused step. Moisturiser follows to help maintain hydration, soften the skin and reduce moisture loss, depending on its formulation.
For a simple routine, there is no need to layer multiple serums. One well-chosen serum followed by a moisturiser may be enough.
A Simple REVEA Hydration Routine
REVEA CALM Barrier Support Serum is a lightweight, fragrance-free serum formulated with Multi-Weight Hyaluronic Acid, Panthenol (Pro-Vitamin B5), saccharide isomerate and glycerin.
The Australian-made formula is designed to help maintain hydration, support moisture balance and leave skin feeling softer, smoother and more comfortable. It is designed for all skin types, including sensitive and dehydrated skin, and can be used morning and evening according to the product directions.
Use it as the first leave-on hydration step:
- CALM Barrier Support Serum — lightweight hydration support
- CALM Barrier Support Cream — moisturising barrier support
For a detailed breakdown of the formula, read REVEA CALM Barrier Support Serum: Ingredients & Benefits.
Frequently Asked Questions About Face Serum
Do I need a face serum?
Not necessarily. Serum is an optional skincare step. It can be useful when you want to add a lightweight product for a particular purpose, such as hydration, but a routine does not need serum simply to be complete.
Does serum go before or after moisturiser?
Serum generally goes before moisturiser because it usually has a lighter texture. Follow the directions supplied with each product.
Can I use face serum every day?
Many hydration-focused serums are designed for daily use. Frequency depends on the formulation and your skin, so follow the product directions and introduce new skincare gradually.
Can I use serum morning and night?
A gentle hydrating serum may be used in both morning and evening routines if its directions support twice-daily use and it suits your skin.
How much face serum should I apply?
Use enough to spread a thin, even layer over the intended area. For an airless pump serum, one or two pumps may be sufficient, but always follow the individual product instructions.
Is face serum suitable for sensitive skin?
It depends on the complete formulation and the individual. Consider fragrance-free options, introduce one new product at a time and patch test before full use. If sensitivity is persistent or severe, seek advice from a qualified health professional.
Is serum the same as moisturiser?
No. A serum is usually a lighter, more targeted product, while a moisturiser commonly combines ingredients that hydrate, soften and help reduce moisture loss. They can be used together rather than treated as substitutes.
Does face serum penetrate more deeply than moisturiser?
Not necessarily. “Serum” describes a product format, not a guaranteed depth of penetration. How an ingredient behaves depends on factors such as its molecular properties, concentration, formulation vehicle and the condition of the skin. It is more accurate to choose a serum for its ingredients, intended cosmetic purpose and suitability for your routine than to assume every serum works at a particular depth.
The Bottom Line
So, what does face serum do? It depends on the formulation. A hydrating face serum can provide a lightweight way to incorporate humectants, support moisture balance and help skin feel softer and more comfortable.
Choose a serum according to your skin’s needs, consider the complete ingredient formula and apply it before moisturiser. A simple, consistent routine is often more useful than layering several products without a clear purpose.
This article provides general cosmetic skincare information and is not medical advice. REVEA CALM products are cosmetics and are not intended to diagnose, treat, cure or prevent a medical skin condition. If you have persistent irritation or a diagnosed skin condition, seek advice from an appropriately qualified health professional.
Written by REVEA Editorial Team
Updated: 11 October 2026
References & Further Reading
- Therapeutic Goods Administration. Determining if your product is a cosmetic or therapeutic good. Australian Government Department of Health, Disability and Ageing.
- Papakonstantinou E, Roth M, Karakiulakis G. Hyaluronic acid: A key molecule in skin aging. Dermatoendocrinology. 2012;4(3):253–258. doi:10.4161/derm.21923.
- Proksch E, de Bony R, Trapp S, Boudon S. Topical use of dexpanthenol: a 70th anniversary article. Journal of Dermatological Treatment. 2017;28(8):766–773. doi:10.1080/09546634.2017.1325310.
- Draelos ZD. The science behind skin care: Moisturizers. Journal of Cosmetic Dermatology. 2018;17(2):138–144. doi:10.1111/jocd.12490.
- Verdier-Sévrain S, Bonté F. Skin hydration: a review on its molecular mechanisms. Journal of Cosmetic Dermatology. 2007;6(2):75–82. doi:10.1111/j.1473-2165.2007.00300.x.
- Rawlings AV, Canestrari DA, Dobkowski B. Moisturizer technology versus clinical performance. Dermatologic Therapy. 2004;17(Suppl 1):49–56. doi:10.1111/j.1396-0296.2004.04s1006.x.
