Oleic Acid – Omega-9 Fatty Acid & Emollient for Cosmetic Formulations

Oleic Acid is a versatile, oil-soluble fatty acid used in skincare, haircare, cleansing products and soapmaking. It is an omega-9 monounsaturated fatty acid that helps condition and soften the skin while improving the spreadability and richness of cosmetic formulations.

It may also be used as a formulation aid, cleansing component and starting material for creating soaps and other surfactant systems. Oleic Acid is particularly useful when developing rich creams, cleansing oils, balms, hair treatments and traditional soap formulations.

Why Formulators Use Oleic Acid

  • Provides emollient and skin-conditioning properties
  • Improves the spreadability of oils, balms and emulsions
  • Adds richness and slip to cosmetic formulations
  • Helps soften dry or rough-feeling skin
  • Supports the dispersion of selected oil-soluble ingredients
  • Can be neutralised with an alkali to produce soap
  • Suitable for skincare, haircare and cleansing formulations
  • Useful for adjusting the sensory profile of an oil phase

Product Information

INCI: Oleic Acid
Chemical name: cis-9-Octadecenoic Acid
CAS number: 112-80-1
Ingredient type: Fatty acid, emollient and formulation aid
Fatty-acid family: Omega-9 monounsaturated fatty acid
Appearance: Clear, colourless to pale-yellow oily liquid
Typical use level: 1–10%
Solubility: Oil-soluble; insoluble in water
Recommended addition: Add to the oil phase
pH: Not applicable as supplied in an anhydrous form

Higher concentrations may be used in specialist applications such as soapmaking. Always follow the supplier’s technical documentation for the specific grade supplied.

How to Use

Oleic Acid is normally incorporated into the oil phase of a cosmetic formulation. It can be combined with cosmetic oils, esters, waxes and other oil-soluble ingredients.

It is liquid at normal room temperatures, although it may become cloudy or partially solidify when stored in cooler conditions. Gentle warming and mixing can restore a uniform liquid consistency.

For soapmaking, Oleic Acid reacts with a suitable alkali to form an oleate soap. Accurate formulation calculations and appropriate protective equipment are essential when working with sodium hydroxide, potassium hydroxide or another alkaline neutralising agent.

Example Calculation

For a 100 g formulation using Oleic Acid at 5%:

Oleic Acid required: 5 g

For a 1 kg formulation using Oleic Acid at 5%:

Oleic Acid required: 50 g

Suitable Formulation Types

Oleic Acid can be used in:

  • Facial and body oils
  • Cleansing oils
  • Cleansing balms
  • Oil-based serums
  • Rich facial creams
  • Body creams and lotions
  • Hand and foot treatments
  • Lip balms
  • Massage oils
  • Hair conditioners
  • Hair masks and treatments
  • Scalp products
  • Traditional soaps
  • Liquid-soap formulations
  • Shaving products

Formulation Ideas

Rich Cleansing Oil

Combine Oleic Acid with lighter cosmetic oils and esters to create a cleansing oil with good slip and makeup-dissolving properties.

Conditioning Cleansing Balm

Use Oleic Acid within the oil phase of a balm formulation to provide richness, spreadability and a conditioned after-feel.

Intensive Body Cream

Add Oleic Acid to the oil phase of a cream designed for dry or rough-feeling areas such as hands, feet, elbows and knees.

Hair and Scalp Oil

Use as part of an oil blend designed to condition dry hair and improve lubrication and manageability.

Traditional Soap

Neutralise Oleic Acid with a correctly calculated amount of alkali to produce a soft, mild-feeling oleate soap base.

Formulation Tips

  • Add Oleic Acid to the oil phase of emulsions and anhydrous products.
  • Combine it with lighter emollients to balance its rich, oily skin feel.
  • Use an antioxidant such as Tocopherol to help protect oxidation-sensitive oil phases.
  • Minimise unnecessary exposure to heat, air and light during manufacturing and storage.
  • Test carefully in clear or pale-coloured formulations, as natural colour variation may affect the finished appearance.
  • Assess the effect of Oleic Acid on viscosity, emulsion stability and skin feel.
  • Confirm compatibility with the chosen emulsifier, surfactant and packaging.
  • Follow the supplier’s recommended use level and technical specifications.

Facial and Acne-Prone Formulations

Oleic Acid can increase the fluidity and permeability of the skin barrier, which may be useful in some specialist formulations. However, higher concentrations can feel heavy and may not be suitable for every skin type.

For facial products—particularly those intended for oily, blemish-prone or sensitive skin—use conservative amounts and evaluate the complete formulation carefully. Avoid making claims that Oleic Acid treats acne or other skin conditions.

Oxidation and Stability

Oleic Acid contains one carbon-carbon double bond and is therefore more susceptible to oxidation than fully saturated fatty acids.

Protect the ingredient and finished formulation from prolonged exposure to oxygen, direct sunlight and excessive heat. An antioxidant can support oxidative stability, but it does not replace an appropriate preservative in products containing water.

Is Oleic Acid a Preservative?

No. Oleic Acid is not a broad-spectrum cosmetic preservative.

Any formulation containing water must use an appropriate preservation system and should undergo stability and microbiological testing before commercial sale.

Storage

Store tightly closed in a cool, dry and well-ventilated place. Protect from direct sunlight, excessive heat and prolonged exposure to air.

Oleic Acid may become cloudy or partially solid at lower temperatures. Gentle warming and mixing can usually restore its normal liquid appearance.

Important Information

This is a cosmetic raw material intended for formulation use. It is not a finished cosmetic product and should not be applied directly to the skin in its supplied form.

For external cosmetic formulation use only. Avoid contact with the eyes. Keep out of reach of children. Wear suitable protective equipment when handling raw materials.

This material is not offered as a food or nutritional supplement.

The formulator is responsible for determining the appropriate use level and assessing the safety, stability, preservation and regulatory compliance of the finished product.

Frequently Asked Questions

What is Oleic Acid?

Oleic Acid is an oil-soluble omega-9 monounsaturated fatty acid. It occurs naturally in many vegetable and animal-derived fats, although the origin and purity of a commercial cosmetic grade must be confirmed through its supplier documentation.

Is Oleic Acid soluble in water?

No. Oleic Acid is insoluble in water and should normally be added to the oil phase of a formulation.

Can Oleic Acid be used in facial products?

Yes, but the concentration should be chosen carefully. It produces a rich emollient feel and may not suit every oily, blemish-prone or sensitive-skin formulation.

Is Oleic Acid the same as olive oil?

No. Olive oil naturally contains a high proportion of oleic acid, but it also contains many other fatty acids and minor components. Cosmetic-grade Oleic Acid is a distinct raw material with its own purity specification.

Can Oleic Acid be used to make soap?

Yes. Oleic Acid reacts with a correctly calculated amount of alkali to form an oleate soap. Soapmaking with strong alkalis requires accurate calculations, suitable equipment and appropriate safety procedures.

Does Oleic Acid need a preservative?

Oleic Acid itself is an anhydrous raw material. However, any finished formulation containing water will normally require a suitable broad-spectrum preservative system.

Why has my Oleic Acid become cloudy?

Cool storage temperatures can cause Oleic Acid to become cloudy or partially solid. Gentle warming and mixing will normally return it to a uniform liquid.