Selection of Oils and Emulsifiers in Skincare Formulation Design

In the development of modern skincare products, consumer demands have extended beyond basic skincare benefits to include product texture and sensory experience as decisive factors for success. A product’s ability to win over users often hinges on their first impression upon application. Behind this sensory experience, oils and emulsifiers serve as two foundational pillars in formulation design, playing critical roles in the process. Oils not only provide exceptional moisturizing, repairing, and nourishing effects but also significantly influence the product’s feel on the skin and absorption rate. Emulsifiers, on the other hand, are responsible for blending the water and oil phases seamlessly, directly impacting the stability and texture of the formulation. From light and non-greasy lotions to silky and rich creams, these subtle yet important differences stem from the meticulous formulation choices made by the development team. So, how can one select the most suitable oils and emulsifiers from an array of options to align with product positioning and meet consumer needs? This article will unlock the secrets to their selection, diving deep into how scientific combinations can achieve optimal texture and performance.

What is Oils and Emulsifiers in Skincare Products?

Oils in Skincare Products
Oils are essential ingredients in skincare products, including plant-based oils, mineral oils, synthetic oils, and lipid substances derived from animal or plant sources. These components are primarily composed of fatty acids and their derivatives, providing lubrication, nourishment, and moisturizing benefits.
Functions
Moisturizing
Oils form a protective barrier on the skin’s surface, reducing water loss and enhancing hydration. For instance, jojoba oil and olive oil effectively lock in moisture.

Repairing the Skin Barrier
Certain oils (e.g., ceramides and shea butter) help repair damaged skin barriers, strengthening the skin’s protective functions.

Enhancing Skin Feel
Oils influence the sensory experience of a product, such as its lightness, richness, or smoothness. For example, grapeseed oil absorbs quickly and feels lightweight, ideal for oily skin, while coconut oil provides a heavier, more nourishing texture, suitable for dry skin.

Contributing to Product Texture
The type and amount of oil directly affect the texture of skincare products, such as the lightness of a lotion or the richness of a cream.

Additional Benefits
Some oils (e.g., rosehip oil and evening primrose oil) are rich in antioxidants and vitamins, helping to combat skin aging.

Emulsifiers in Skincare Products
Emulsifiers are a type of surfactant used to mix water and oil phases, creating a stable emulsion system. Their amphiphilic molecular structure, containing both hydrophilic and lipophilic groups, allows water and oil to coexist harmoniously.
Functions
Stabilizing Emulsions
Emulsifiers reduce the surface tension between the water and oil phases, enabling the formation of a stable emulsion and preventing separation or breakdown. For example, glyceryl stearate is a commonly used emulsifier.

Enhancing Texture
Different emulsifiers influence the sensory properties of a product, such as creating a lightweight feel (oil-in-water, O/W) or a richer feel (water-in-oil, W/O).

Improving Uniformity
They ensure the even distribution of active ingredients within a formulation, maximizing the product’s efficacy.

Adapting to Different Formulation Needs
Emulsifiers are selected based on the product type. For example, natural or mild emulsifiers (e.g., lecithin) are often used in formulations designed for sensitive skin.

Common Types of Oils in Skincare Products and Their Characteristics

1. Plant Oils
Jojoba Oil:
Characteristics: Similar in structure to sebum, easily absorbed, lightweight, and non-greasy.
Suitable Skin Types: All skin types, especially oily and sensitive skin.
Benefits: Moisturizing, sebum regulation, and skin barrier repair.

Coconut Oil:
Characteristics: Rich in medium-chain fatty acids, thick texture, highly nourishing.
Suitable Skin Types: Dry and rough skin; use cautiously on acne-prone skin.
Benefits: Deep hydration, skin softening, and mild antibacterial properties.

2.Synthetic Oils
Dimethicone:
Characteristics: Lightweight, silky texture, enhances sensory feel.
Suitable Skin Types: All skin types, especially oily skin.
Benefits: Provides a smooth finish, locks in moisture, and improves product feel.

Synthetic Esters:
Characteristics: Lightweight, non-greasy, highly stable, and customizable for different formulations.
Common Types: Caprylic/Capric Triglyceride, Isopropyl Myristate, Ethylhexyl Palmitate.
Benefits: Provides moisturization, enhances texture, improves absorption, and increases formula stability.

3. Mineral Oils
Vaseline
Characteristics: Highly stable, occlusive, forms a protective barrier to lock in moisture.
Suitable Skin Types: Dry, extremely dry, or damaged skin; ideal for use in cold or dry environments.
Benefits: Deep moisturization, skin barrier repair, soothes dryness, softens rough skin, and prevents moisture loss.

Petroleum Jelly (Mineral Oil):
Characteristics: Colorless, odorless, forms a physical barrier on the skin.
Suitable Skin Types: Dry or sensitive skin.
Benefits: Locks in moisture, repairs the skin barrier, but may feel heavy and occlusive.

Liquid Paraffin:
Characteristics: Provides skin lubrication and enhances smoothness.
Suitable Skin Types: Dry skin but may feel greasy for some users.
Benefits: Moisturizes and prevents water loss.

Common Types of Emulsifiers and Their Applications

1. Natural Emulsifiers
Natural emulsifiers are derived from natural sources such as plants, animals, or microorganisms. They are widely used in skincare products, especially for sensitive skin and organic cosmetics due to their gentle and eco-friendly properties.
Characteristics: Natural Origin: Sourced from plant oils, animal fats, or plant extracts, they are non-toxic and skin-friendly. Biodegradable: These emulsifiers are environmentally friendly and easily biodegradable. Gentle on Skin: They are less likely to cause irritation, making them suitable for sensitive skin types.
Common Types and Applications:
Lecithin
Application: Used in creams, lotions, serums, and emulsions to help disperse oil and water phases, providing moisture and lubrication to the skin.

Evening Primrose Oil
Application: Used in skincare formulations to balance oil and water, and to soothe dryness and irritation.

Vegetable Glycerin
Application: Widely used in moisturizers and cleansers to regulate the skin’s moisture levels and enhance skin hydration.

Advantages: Eco-friendly, suitable for organic skincare. Gentle on the skin, reducing the risk of irritation, especially for sensitive skin.

2. Nonionic Emulsifiers

Nonionic emulsifiers do not carry an electrical charge, making them mild, stable, and compatible with a wide range of ingredients. These emulsifiers are ideal for most skincare products, providing smooth texture and ease of use.
Characteristics: Mildness: These emulsifiers are less likely to irritate the skin since they are free from charges. Stability: They maintain formula stability across various pH levels and help keep emulsions uniform over time. High Compatibility: Nonionic emulsifiers blend well with other ingredients, making them suitable for complex formulations.
Common Types and Applications:
Tween (Polysorbate)
Application: Widely used in lotions, creams, cleansers, etc., to stabilize oil and water phases and improve product texture.

Polysorbate 20
Application: Used in lotions, toners, and cleansers to stabilize oil and water emulsions and improve texture.

Steareth-20
Application: Commonly used in creams, lotions, and serums, this emulsifier improves texture and helps emulsify oil and water phases.

Glyceryl Stearate
Application: Used in moisturizers and emulsions to provide stability and enhance skin feel.

Advantages: Great stability, suitable for most skincare formulations. Mild and non-irritating, perfect for daily use on all skin types.

3. New Generation Emulsifiers

New generation emulsifiers are innovative and designed to offer enhanced performance, often incorporating multiple functionalities. These emulsifiers are used in high-end skincare products and advanced formulations for targeted benefits.
Characteristics: Innovative: These emulsifiers often feature unique properties or functionalities, such as improved emulsification efficiency or multi-functional benefits. Efficiency: They can emulsify effectively at low concentrations, reducing the amount needed in formulations. Specialized Functions: Some new generation emulsifiers not only stabilize emulsions but also offer additional benefits like anti-aging, antioxidant properties, or oil control.
Common Types and Applications:
Biopolymer-based Emulsifiers
Application: Derived from plant proteins, these emulsifiers are used in anti-aging, moisturizing formulations to improve skin elasticity and hydration.

Lecithin-based Emulsifiers
Application: Common in high-end skincare products such as serums and creams, lecithin provides deep moisture and helps maintain the skin barrier.

Polymer Emulsifiers
Application: Used in sunscreens, repair creams, and other specialized skincare products to stabilize formulations and enhance skin feel.

Advantages: Provide superior emulsification and stability. Can offer multiple benefits (e.g., anti-aging, hydration) in addition to emulsification, making them ideal for advanced formulations.

How to Choose Oils and Emulsifiers Based on Product Needs？

1. Skin Type and Needs
Dry Skin: For dry skin, choose oils rich in moisturizing, repairing, and nourishing properties, such as plant oils (e.g., olive oil, almond oil) and synthetic esters (e.g., isododecane, caprylic/capric triglycerides). Choose gentle, moisturizing emulsifiers, such as natural emulsifiers (e.g., lecithin) or nonionic emulsifiers (e.g., Polysorbates).
Oily/Mixed Skin: For oily or mixed skin, choose lightweight oils that help control oil and improve pore issues, such as jojoba oil and tea tree oil. Choose lightweight, non-greasy emulsifiers, such as nonionic emulsifiers (e.g., Polysorbate-20) or some hydrophilic emulsifiers (e.g., glyceryl stearate), to avoid adding excess greasiness.
Sensitive Skin: For sensitive skin, choose biocompatible and gentle oils like evening primrose oil or squalane, and use low-irritant, non-sensitizing emulsifiers (e.g., plant-derived emulsifiers). Avoid synthetic emulsifiers or highly irritating oils.

2. Product Functionality
Anti-Aging: For anti-aging products, use oils rich in antioxidants, such as rosehip oil and grapeseed oil, which contain vitamin C and E to aid in repair and protect against oxidative stress. Emulsifiers should include stable nonionic emulsifiers (e.g., Polysorbates) and new-generation emulsifiers (e.g., plant-derived bioemulsifiers) to enhance skin barrier function and provide long-lasting hydration
Whitening/Brightening: For brightening products, oils that help enhance skin brightness, such as sunflower oil and almond oil, are beneficial. Emulsifiers should be refreshing and non-greasy, such as nonionic emulsifiers (e.g., polyethylene glycol stearate), ensuring the product absorbs quickly.

3. Product Texture Needs
Lightweight Products: For products that require a lightweight texture (e.g., toners, light lotions), choose refreshing oils that absorb easily, such as coconut oil or grapeseed oil. Emulsifiers should be low-viscosity and capable of forming stable oil-water emulsions, such as Polysorbates or glyceryl stearate, which contribute to a light, non-greasy feel.
Rich Texture Products: For richer textures (e.g., creams, deep nourishing creams), heavier oils such as shea butter or cocoa butter provide more intense moisture and repair. Emulsifiers should be stable and enhance texture, such as natural emulsifiers (e.g., lecithin) or certain polymer emulsifiers that add richness and stability to the formula.

4. Product Stability and Sensory Feel
Product Stability: The choice of emulsifier directly affects product stability, especially in formulas with high oil-to-water ratios. Choosing emulsifiers that provide long-term stability is key, such as nonionic emulsifiers (e.g., Polysorbates) or polymer emulsifiers, which help maintain uniformity over time without separation.
Sensory Feel: Sensory feel refers to the feeling a product gives when applied. The choice of oils and emulsifiers directly impacts this. For instance, some oils (e.g., glycerin, olive oil) provide a smooth, lubricating feel, while synthetic esters offer a lighter, non-greasy texture. Choosing the right emulsifier (e.g., shea butter with Polysorbates) can give products a better glide and skin-feel.

Key Factors Influencing Skincare Formulation Design

1. HLB Calculation and Matching
HLB (Hydrophilic-Lipophilic Balance) is a key factor in determining the hydrophilic (water-loving) and lipophilic (oil-loving) properties of emulsifiers. It plays a crucial role in the selection of emulsifiers and formulation design. Based on the type of emulsion (oil-in-water or water-in-oil), calculating and matching the HLB value ensures product stability and emulsification performance.

HLB Calculation and Selection
Oil-in-water (O/W) Emulsion: For oil-in-water emulsions (where oil is dispersed in water), emulsifiers with higher HLB values (typically between 8 and 16) are chosen. These emulsifiers are more hydrophilic and are effective at stabilizing the water phase, forming a uniform emulsion.
Water-in-oil (W/O) Emulsion: For water-in-oil emulsions (where water is dispersed in oil), emulsifiers with lower HLB values (typically between 3 and 6) are preferred. These emulsifiers are more lipophilic, helping to stabilize the oil phase and form a stable emulsion.

Role of HLB Matching
Emulsion Stability: Proper HLB matching ensures that the oil and water phases are effectively combined, preventing separation or stratification. A balanced HLB value also prevents overuse or insufficient use of emulsifiers, optimizing both performance and cost.
Texture Adjustment: By adjusting the HLB values, formulators can influence the viscosity and texture of the product. Higher HLB emulsifiers tend to result in lighter, fresher textures, while lower HLB emulsifiers contribute to richer, more emollient formulations.

2. Sensory Feel and Absorption Optimization
Sensory feel and absorption are key factors that directly impact consumer experience and product acceptance. Optimizing these aspects in formulation design is critical.
Optimizing Sensory Feel
Choice of Oils: The type of oil selected affects the product’s sensory feel. Lightweight oils (e.g., jojoba oil, grape seed oil) are ideal for products that need a non-greasy, refreshing feel, while heavier oils (e.g., shea butter, cocoa butter) provide a richer, more emollient feel.
Choice of Emulsifiers: Different emulsifiers affect the sensory feel of the product. Nonionic emulsifiers (e.g., Polysorbates) typically provide a smoother, more elegant feel, suitable for daily-use products, while natural emulsifiers (e.g., lecithin) offer a gentler, more comfortable feel, which is ideal for sensitive skin.

Optimizing Absorption
Oil Absorption: Some oils (e.g., jojoba oil, caprylic/capric triglycerides) are quickly absorbed by the skin, while thicker oils (e.g., mineral oil, shea butter) may take longer to absorb. By adjusting the oil blend, formulators can optimize the absorption rate for a faster or slower finish.
Emulsifier Selection: Nonionic emulsifiers typically allow for quicker absorption, as they don’t form a thick layer on the skin, while hydrophilic emulsifiers (e.g., Polysorbates) improve the penetration of water-based ingredients, enhancing absorption.

3. Safety and Allergy Risk
Safety and the potential for allergic reactions are paramount concerns for consumers. The selection of ingredients must be carefully considered to ensure mildness and avoid irritation or allergies.
Controlling Allergenic Ingredients
Avoiding Allergens: Certain ingredients, such as fragrances, specific preservatives (e.g., phenoxyethanol), and alcohol, are more likely to cause allergic reactions or skin irritation. Reducing or replacing these with mild, natural alternatives (e.g., plant extracts, organic oils) can lower the risk of adverse reactions.
Allergy Testing: During the development process, it is important to conduct skin irritation and allergy tests to ensure that the formulation is safe for sensitive skin and will not cause allergic reactions.

Ensuring Safety
Ingredient Source and Purity: It’s critical to select high-quality raw materials that are free from harmful substances, such as heavy metals or pesticide residues, to ensure the safety of the final product.
pH Balance and Skin Compatibility: The pH of the product should be close to the skin’s natural pH (around 4.5-5.5) to maintain the skin’s barrier function and avoid irritation or dryness.

In the future, oils and emulsifiers in skincare products will evolve towards being natural, sustainable, effective, safe, and personalized. As consumers increasingly demand natural ingredients and environmentally-friendly options, plant-derived oils and renewable emulsifiers will become the mainstream choice. At the same time, functional oils and emulsifiers will offer more than basic moisturizing; they will provide multi-functional benefits such as anti-aging and skin repair to meet the growing diversity of skincare needs. The demand for skin-friendly and sensitive-skin formulations will drive the use of milder, less irritating ingredients. Additionally, the incorporation of smart formulations and nanotechnology will enhance absorption and efficacy, while trends in ingredient transparency and traceability will strengthen consumer trust in brands. In summary, the selection of oils and emulsifiers will focus more on effectiveness, comfort, and sustainability, driving the skincare industry toward greater innovation and personalization.