What They Are, How They Work, and How to Choose the Right One

A lightweight fluid, a mid-weight cream, and a 10% urea formula can all be considered moisturizers—but they address different skincare needs and preferences. Understanding how moisturizers perform can help you determine which are best for your skin. Below, a full guide to moisturizing formulas and how they function.

What Is a Moisturizer?

A moisturizer is a cosmetic product designed to increase skin hydration, reduce transepidermal water loss (TEWL), and support skin barrier function. They work by increasing water content within the stratum corneum while reinforcing the lipid matrix that helps retain moisture. As hydration improves, skin appears smoother, softer, and more resilient.

Unlike OTC skin protectants, moisturizers are not regulated as drug products and do not make therapeutic claims such as temporarily protecting injured skin. Their function is hydration and barrier maintenance—not wound protection.

How Moisturizers Support the Skin Barrier

The skin barrier is composed of corneocytes held together by a lipid matrix made up of ceramides, cholesterol, and fatty acids. Both water content and lipid integrity determine barrier performance.

Moisturizers help improve barrier function through three primary mechanisms: increasing water content, replenishing barrier lipids, and reducing excessive water loss.

When hydration is balanced and the lipid matrix is intact, skin appears smoother, less reactive, and more comfortable.

Most moisturizers rely on a combination of humectants, emollients, and barrier lipids to improve skin performance:

• Humectants such as glycerin, sodium hyaluronate, saccharide isomerate, amino acids, and urea attract and bind water within the stratum corneum. (At 10%, urea functions as both a humectant and a mild keratolytic, meaning it increases hydration while helping loosen dead skin cell cohesion to improve texture.)
• Emollients including squalane, jojoba oil, ethylhexyl stearate, polyglycerides, and shea butter smooth and soften by filling gaps between skin cells. This improves surface texture and flexibility without necessarily increasing water content directly.
• Bio-engineered barrier lipids such as ceramides, cholesterol, and essential fatty acids like linoleic and linolenic acid help replenish the skin’s natural lipid matrix. These ingredients support long-term barrier integrity and reduce transepidermal water loss.

Texture and Weight: How Format Affects Use

Moisturizers vary in texture, weight, and format—which influences how a product fits into a routine. A lightweight fluid emulsion offers flexibility and layerability; a mid-weight cream provides foundational daily hydration; a moisturizer containing 10% urea offers hydration combined with mild exfoliation.

Texture affects feel and layering behavior, but it does not determine regulatory classification. All three remain cosmetic moisturizers, even when their functional strength differs.

Selecting the appropriate weight depends on skin type, climate, and whether the formula will be used alone or layered.

How to Choose the Right Prequel Moisturizer

Half & Half Fluid Moisturizer

Half & Half Fluid Moisturizer is a lightweight emulsion formulated with 1% dermo-mimetic ceramide NP in an olive-derived lipid matrix, a peptide complex, and an amino acid blend. This formula can function as a standalone moisturizer in oily or humid conditions or as a hydrating layer beneath a richer cream. It absorbs easily and leaves a supple, natural finish without heaviness.

Half & Half is well suited for oily or combination skin, for layering under retinoids in a “sandwich” method, and for climates where lightweight hydration is preferred. Half & Half Fluid Moisturizer has received the National Eczema Association (NEA) Seal of Acceptance and National Psoriasis Foundation (NPF) Seal of Recognition.

AM/PM Modern Moisturizer

AM/PM Modern Moisturizer is a true mid-weight cream designed for twice-daily use across skin types. It combines a multi-ceramide blend with a ferment-peptide complex, glycerin, polyglycerides, vitamin F, and saccharide isomerate to support barrier integrity and visible smoothing.

This formula functions as a reliable daily moisturizer for ongoing barrier support. It provides consistent hydration, supports overall skin barrier health, and improves skin softness and texture over time.

AM/PM is appropriate for most skin types seeking a reliable morning and evening moisturizer that reinforces the barrier without ever feeling heavy or greasy. AM/PM Modern Moisturizer has received the National Eczema Association (NEA) Seal of Acceptance, National Psoriasis Foundation (NPF) Seal of Recognition, and National Rosacea Society (NRS) Seal of Acceptance

Urea Advanced Relief 10% Moisturizing Milk

Urea Advanced Relief contains 10% pure urea, a natural moisturizing factor component that increases water binding capacity while functioning as a mild keratolytic. Combined with glycerin, shea butter, niacinamide, and a sterol-rich emulsifier blend, the formula hydrates while improving rough or flaky texture.

At this concentration, urea softens rough, scaly, or uneven areas while supporting hydration. It is suitable for both face and body and is often chosen for concerns such as keratosis pilaris or persistent roughness.

Because 10% urea increases permeability and promotes mild exfoliation, it may not be universally tolerated for twice-daily use in highly sensitive skin. Frequency should be adjusted based on individual tolerance. Urea Advanced Relief Moisturizing Milk has received the National Eczema Association (NEA) Seal of Acceptance and National Psoriasis Foundation (NPF) Seal of Recognition.

Hand Wrap Hand Shielding Lotion for Dry Hands

Hand Wrap Shielding Lotion is a hand lotion for dry hands designed to support the skin barrier during frequent washing and daily exposure. It forms a flexible, lightweight film to help prevent moisture loss, even after washing.

Choosing the right Prequel moisturizer depends on primary skin goals and environmental factors. Here’s a quick guide, at a glance:

• If the goal is lightweight hydration or a layerable formula, Half & Half is right for you.
• If the goal is a consistent, twice-daily essential cream that supports barrier integrity and visible smoothness, AM/PM functions as a foundational moisturizer for most skin types.
• If the goal is hydration combined with texture refinement—particularly for rough, flaky, or scaly areas—Urea Advanced Relief provides both humectant support and mild exfoliation.

Each formula serves a different purpose. Selection should be based on skin condition, ingredient tolerance, and routine.

Can You Layer Moisturizers?

Moisturizers can be layered when additional hydration or barrier support is needed.

A common approach is to apply a lightweight fluid moisturizer first, followed by a mid-weight cream. This increases hydration while preserving compatibility and absorption.

When using retinoids, Half & Half may be layered to create a moisturizing “sandwich”: Apply before to support hydration and follow with another layer of Half & Half as the final step of your routine.

How Often Should You Use a Moisturizer?

Most skin types benefit from moisturizer use at least once daily, and many individuals prefer twice-daily application.

Frequency should be adjusted based on climate, skin type, active treatments, and tolerance to keratolytic ingredients such as 10% urea.

Moisturizers are designed for ongoing hydration and barrier maintenance rather than short-term correction.

Moisturizers vs Skin Protectants

Moisturizers are cosmetic products formulated to hydrate and support the skin barrier.

Skin protectants are OTC drug products formulated with FDA-recognized active ingredients designed to temporarily protect compromised skin.

While both categories can support barrier function, they serve different regulatory and functional roles. Understanding that distinction helps guide appropriate product selection.

Choosing the Right Level of Hydration

Skin hydration needs can shift based on environment, routine, and skin condition.

Lightweight formulas may be sufficient in humid climates or for oily skin types. Mid-weight creams may be appropriate for daily barrier maintenance. Active moisturizers such as 10% urea formulas are better suited for targeted texture concerns. Choose the level of hydration based on the skin’s current condition and texture needs.

When hydration levels are balanced, skin appears smoother, more supple, and more resilient. As always, consult with your physician or dermatologist for any additional information for your particular skin type and needs.

DISCLAIMER: All skin care articles are intended to help educate on specific ingredients and skin care topics. Our articles are written to be informative and informational. Any reference to a specific patient experience is not a medical suggestion for treatment. Please note that any Prequel products with referenced ingredients are formulated for Cosmetic Use Only and NOT intended as replacements for physician advice and/or pharmaceutical product recommendations.