When you start building a skincare routine, certain essentials are no-brainers (think universal staples like cleanser, moisturizer, and sunscreen). But beyond that, it’s a little less cut-and-dry. You may find yourself wondering whether it’s worth it to add a face serum to the mix. Frankly, you wouldn’t be alone: Serum-related queries (like “do serums work” and “what do serums do”) are among the questions that we receive most frequently from Kiehl’s customers. Our answer is always the same—face serum can be a huge asset to your skincare routine if you choose the right formula for your skin type and concerns.

Here, we’ll teach you how to use face serum and answer your most pressing questions about this versatile skincare essential, including when, where, and how to apply serum. We’ll also introduce you to some of our favorite formulas and provide recommendations on the best Kiehl’s serum for your needs. Settle in and read on for the all-in-one Kiehl’s guide to skincare serums.

What Is a Face Serum?

A facial serum is a targeted skincare treatment designed to address one or more skin concerns, such as fine lines and wrinkles or dullness. Serums are generally thin, spreadable liquids, though they may also come in slightly thicker gel and cream formulations. They usually feature concentrated doses of active ingredients in a water-based matrix. The lightweight consistency of serums enables these active ingredients to penetrate the skin’s deeper layers for targeted treatment. For this reason, we consider serums to be a crucial step in an effective skincare routine.

What Do Face Serums Do?

While most serums provide some level of hydration for the skin, the exact benefit of any given serum will depend largely on the ingredients and the skin concern(s) it's meant to address. Lightweight serums with vitamin C, for example, generally target issues such as dullness and discolorations. Formulas that contain hyaluronic acid, on the other hand, may be designed to make skin appear plumper.

What Is The Difference Between a Face Serum and an Oil?

Serums differ from facial oils in that they are typically water-based and devoid of heavier oils. At Kiehl’s, our serums are sometimes labeled as "solutions" or "treatments" to indicate potency. While also rich in active ingredients, facial oils tend to be formulated with emollients and are slightly heavier and thicker in consistency. In general, we recommend applying your skincare products in order of weight, starting with the lighter, water-based formulas and ending with the heavier products. As such, oils are usually applied at the end of your skincare routine to help trap in moisture and nourish the skin. Serums, by contrast, are applied earlier—usually after cleansing and toning.

What Do Different Serums Do For The Skin?

At Kiehl’s, we offer a range of skincare serums for various skin types. Here, discover some of the different face serums available at Kiehl’s and learn what these powerful formulas can do for your skin.

Anti-Aging Serums

Anti-aging serums typically target an array of age-related skin concerns, like fine lines, wrinkles, and a loss of elasticity. What formula you choose depends largely on your skin type and the extent of your age-related concerns.

Guys looking for an anti-aging serum designed specifically for men’s skin, meanwhile, can try Age Defender Power Serum. The anti-wrinkle serum with cypress extract and adenosine firms the skin and helps address the visible signs of aging. The easy-to-use formula, which is lightweight and absorbs quickly, is a great option for all men’s skin types.

Hydrating Serums

The primary purposes of hydrating serums are to moisturize, soften, and visibly plump the skin. To enjoy these benefits, we recommend adding an extra dose of hydration to your skincare routine with Hydro-Plumping Hydrating Serum. The gentle serum helps replenish dehydrated skin, leaving it looking plumper, smoother, and firmer with regular use. It’s suitable for all skin types and can be used morning and night—even around the eye contour—for visibly more hydrated skin.

Exfoliating Serums

Those who frequently deal with dull, lackluster-looking skin may benefit from adding an exfoliating serum to their regular skincare routine. These formulas typically include chemical exfoliants, such as alpha or beta-hydroxy acids, to help slough off dead surface skin and promote a more glowing appearance. You can multitask and exfoliate while you sleep with Nightly Refining Micro-Peel Concentrate. This nighttime serum with phytic acid and quinoa husk extract is clinically-demonstrated to help accelerate skin surface turnover, refining both skin texture and tone.* Apply the exfoliating formula before bed for visibly refreshed, radiant-looking skin by morning.

*Based on an instrumental test within surface layers.

Skin-Strengthening Serums

Broadly speaking, skin-strengthening serums are formulas that help support your skin’s natural moisture barrier (the integrity of which is imperative for healthy-looking skin). They can help with a wide range of skin concerns and may be used daily to help boost the skin’s resilience. Our favorite skin-strengthening serum is Vital Skin-Strengthening Hyaluronic Acid Super Serum. It’s made with a carefully-selected blend of adaptogenic herbs, plus an engineered form of hyaluronic acid that penetrates deep into the skin. It’s clinically-demonstrated to double skin’s strength while neutralizing the effects of aging skin stressors, giving way to a more radiant, healthy appearance over time.*

*Based on Strength Index = Composite, average score of clinically graded parameters after using the product for 4 weeks vs one week of use.

Eye Serums

Eye serums are pretty straightforward: They’re serums that are specifically designed for use around the eyes. Oftentimes, they can help address concerns specific to the eye area, like dark circles or puffiness. Our Powerful-Strength Dark Circle-Reducing Vitamin C Eye Serum is one such example. The potent, vitamin C-packed treatment instantly smooths and hydrates the under-eye area to help refresh the appearance of tired eyes. With regular use, it visibly diminishes dark circles, helps improve the appearance of crow’s feet, and reduces puffiness. Plus, it’s suitable for all skin types. Use it alone for fresher, brighter-looking eyes or layer it under a richer eye cream for an added dose of nourishing hydration.

How To Use Serum In Your Skincare Routine

Finding the right face serum for your skin’s needs is only part of the battle—equally important is knowing how to apply facial serum properly.

To apply a daily serum, you’ll first need to thoroughly cleanse your skin (if you need help picking a face wash, check out our article The Best Face Wash For Your Skin Type). Then, after rinsing your cleanser off, use a cotton pad to apply toner to your face.

Once your skin is dry, you can apply your serum. Dispense two to three pumps of the serum onto your palm and use clean fingertips to gently pat the formula onto your skin. It’s generally best to avoid rubbing, as this can pull at the skin and lead to wrinkles and sagging skin down the line. Make sure when applying your serum to avoid your eye area unless the formula explicitly states it’s safe to use around the eyes.

Allow the formula to absorb fully, so there’s no tacky or sticky feel, and then continue with your skincare routine, applying eye cream, moisturizer, and sunscreen as needed.

How Often Should You Use Serum On Your Face?

Most serums can be used daily, though it’s always a good idea to read the instructions on the product you’re using before incorporating it into your routine. If you have more than one skin concern you’d like to address, consider designating one serum for your morning skincare routine and a different, complementary one for your nighttime skincare routine—this way, you can reap the benefits of both formulas.

Next: 8 Common Skincare Mistakes Made When Applying Products