Key Takeaways

• Hydrating and moisturizing tend to describe two different jobs: Hydrating ingredients help attract water to the skin’s upper layers, while moisturizing ingredients may help skin feel softer and slow how quickly that water evaporates.

• Humectants, such as Glycerin and Hyaluronic Acid, typically do the hydrating, and emollients and occlusives, such as Shea Butter, Dimethicone, and Petrolatum, typically do the moisturizing.

• “Dehydrated” usually refers to skin that seems short on water, while “dry” more often points to skin that seems short on the oils and lipids that help hold water in, and the two can overlap.

• Most moisturizers combine humectants, emollients, and occlusives, so for many people one well-chosen moisturizer may cover both jobs, and a separate hydrating serum is optional.

• For dry-feeling skin on the face, the American Academy of Dermatology suggests short, warm showers, a gentle cleanser, and a cream or ointment applied while skin is still damp.

Hydrating and Moisturizing Do Two Different Jobs

The two labels get swapped constantly on packaging and in skincare advice. Hydrating usually means helping skin take in and hold on to water. Moisturizing usually means helping it keep that water, by softening the skin and slowing evaporation. Which one do you need? Most skin tends to do best with both, and most moisturizers are built to do some of each.

Below, we walk through how skin tends to lose water, the ingredient types that do the work, how to tell dehydrated-looking skin from dry-feeling skin, and how to layer products so each one has a job. We finish with what to look for on a moisturizer label, and answers to the questions readers ask most.

How Skin Tends to Lose Water Through the Day

Your skin tends to give up a little water through the day, and that’s normal. Some of it evaporates out through the upper layers, a process researchers call “transepidermal water loss,” or TEWL. The lipids packed into those upper layers, largely Ceramides, Cholesterol, and fatty acids, help slow that evaporation, and they’re a large part of what skincare means by the moisture barrier.

When that lipid mix is disrupted, water tends to escape faster. A 2022 review of moisturizers in the journal Medicina describes truly dry skin as having a disorganized lipid layer with a lower share of Ceramides, and it links that change to an increase in transepidermal water loss. The same review lists ultraviolet rays, surfactant-based detergents, friction, and even too much time soaking in water among the things that may disrupt the lipid layer.

So hydrating ingredients help bring water to the upper layers, and moisturizing ingredients help keep it from leaving as quickly. Skin that gets only the first half may feel comfortable at first and tighter later in the day.

Humectants, Emollients, and Occlusives Compared

Nearly every moisturizer is a blend of humectants, emollients, and occlusives, and the Medicina review notes that most formulas mix them. Here’s what each tends to do, with examples you’re likely to see on an ingredient list.

The categories overlap more than a table suggests. According to the same review, Lanolin, Mineral Oil, and Petrolatum work as both emollients and occlusives, and plant oils and butters, such as Grapeseed Oil and Shea Butter, sit with the occlusives. It also notes that Petrolatum and Mineral Oil are among the most effective sealing ingredients available.

One detail from the review matters for your routine: Water loss can increase when a humectant is applied on its own, which is why humectants are usually paired with an occlusive. So a Hyaluronic Acid serum with nothing over it may not hold on to that water for long, and a moisturizer on top may help close that gap.

Dehydrated Skin vs. Dry Skin

The terms “dehydrated” and “dry” often get used interchangeably, but they don’t mean quite the same thing. “Dehydrated” usually describes skin that seems short on water. “Dry” more often describes skin that seems short on the oils and lipids that help hold water in, which is closer to how the Medicina review explains truly dry skin.

At least one research team has measured the two separately. In a 2022 skin-type study in the Journal of the European Academy of Dermatology and Venereology, the researchers used one instrument for water content and another for oil, and classed “dehydrated” and “oily” as separate skin types. That suggests a face can look shiny by midday and still feel tight after cleansing.

The Medicina review describes dry skin as often coming with a pulling or tight feeling, roughness, a duller look, and flaking. In practice, the difference is mostly about what each tends to respond to. Skin that mostly seems short on water may get the most from a humectant layer under a moisturizer. Skin that seems short on oil may want a richer cream with more emollients and occlusives. Most people fall somewhere in between, which is one reason a moisturizer that combines both kinds of ingredients is a sensible default.

How to Layer Hydrating and Moisturizing Products

The order you apply products in tends to matter, because a humectant needs water to work with and a moisturizer on top helps hold that water in.

• Start with damp skin: The AAD suggests applying moisturizer while your skin is still damp after a shower or bath. The Medicina review adds that occlusives tend to slow water loss most effectively when applied right after washing or bathing.

• Apply the hydrating layer first: If you use a humectant serum, such as one built on Hyaluronic Acid or Glycerin, it usually goes on before your moisturizer.

• Finish with a moisturizer that seals: A moisturizer with emollients and occlusives over the top may help keep the water your serum attracted from evaporating as quickly.

• Match the texture to your skin type: The AAD notes that ointments and creams add more moisture than lotions. The Medicina review suggests an ointment or richer cream for dry skin and a lotion or water-based cream for oily skin.

• Adjust with the season: The same review suggests a lighter, more hydration-focused product in summer and a richer cream with more occlusives in winter.

What to Look For on a Moisturizer Label

An ingredient list can tell you which job a moisturizer leans toward. The FDA requires cosmetic ingredients to be listed in descending order of predominance, with an exception for ingredients at 1% or less, which can follow in any order, so the first few entries tend to say the most about the formula.

• A humectant near the top for hydrating: Glycerin, Hyaluronic Acid, Urea, Sorbitol, and Propylene Glycol all sit in the humectant family, and one of them in the first few lines suggests the formula leans into the hydrating job.

• Emollients and occlusives for moisturizing: Dimethicone, Petrolatum, Mineral Oil, Shea Butter, and plant oils tend to do the sealing and softening. Fatty alcohols, such as Cetyl Alcohol and Stearyl Alcohol, are emollients too, and the Medicina review notes that, unlike astringent alcohols, such as Isopropyl Alcohol, they tend not to dry the skin.

• Ceramides and Cholesterol for the moisture barrier: Lipids like these resemble the ones already in the skin’s upper layers, and the Medicina review describes lipid mixtures as a standard moisturizer component that may help support the moisture barrier alongside an occlusive.

• “Fragrance-free” rather than “unscented”: For dry, sensitive-feeling skin, the AAD recommends products labeled “fragrance-free,” since an “unscented” product can contain chemicals that mask other odors, and those may irritate dry skin.

• Comparing specific formulas: For moisturizers compared side by side on ingredient lists, texture, and price, see our comparison of the best face moisturizers for sensitive skin.

When to See a Dermatologist

If dry-feeling skin on your face doesn’t settle after you’ve tried gentler habits, the AAD suggests seeing a board-certified dermatologist, since ongoing dryness can sometimes point to an underlying condition, such as atopic dermatitis or psoriasis. The AAD also suggests telling a dermatologist if anything you apply, moisturizer included, burns or stings.

Frequently Asked Questions

What is the difference between hydrating and moisturizing?

Hydrating usually refers to adding water to the skin, mostly through humectants, such as Glycerin and Hyaluronic Acid, that attract water to the upper layers. Moisturizing usually refers to keeping that water in: Emollients help skin feel softer and look visibly smoother, and occlusives help slow water loss. Most moisturizers do some of both, so the labels tend to describe which job a product leans toward. They aren’t two separate kinds of product.

What helps dry skin on the face?

The AAD’s tips for dry skin include keeping showers and baths to five to 10 minutes in warm water, washing with a gentle cleanser, applying moisturizer while skin is still damp, choosing a cream or ointment over a lotion, and running a humidifier. Ingredients the AAD suggests looking for include Glycerin, Hyaluronic Acid, Dimethicone, Shea Butter, and Petrolatum. It may also help to work out whether your skin seems dehydrated or dry, since dehydrated-looking skin may respond well to a humectant layer and dry-feeling skin to a richer cream. If the dryness persists, a dermatologist can help work out what’s behind it.

Do I need a hydrating serum if I already use a moisturizer?

Not necessarily. Most moisturizers combine humectants with emollients and occlusives, so one well-chosen formula may cover both jobs. A separate humectant serum tends to earn its place when skin still feels tight or looks dull with a moisturizer alone, or when the air is drier. If you use one, apply it first and follow with your moisturizer.

Can oily skin be dehydrated?

It can seem that way. Oil and water content are different measurements, and in the 2022 skin-type study mentioned above, researchers classed “oily” and “dehydrated” as separate skin types. So skin that looks shiny may still feel tight after cleansing. A lightweight humectant layer under a lotion is a common place to start.

Is Hyaluronic Acid hydrating or moisturizing?

Hyaluronic Acid is a humectant, so it’s mainly hydrating. The Medicina review notes that larger humectants, such as Hyaluronic Acid, tend to hydrate the outermost layers, and that humectants are usually paired with an occlusive because a humectant on its own may let water loss increase. That’s why you’ll often find it in moisturizers alongside oils, butters, or silicones.

Related Reading

• How to support your moisture barrier, step by step

• The best non-stripping face cleansers for a gentler routine