Arachidic Acid

Concerns
Malassezia Feeding

What is Arachidic Acid?

Arachidic acid, chemically known as icosanoic acid, is a straight-chain saturated fatty acid with 20 carbon atoms (C20:0). It occurs naturally in trace amounts in plant oils such as peanut oil, rapeseed oil, and tall oil, as well as in some animal fats. This lipid's structure includes a long hydrophobic tail and a hydrophilic carboxylic head, enabling it to interact effectively at oil-water interfaces. In skincare and haircare products, it appears mainly in cleansers, shampoos, body washes, lotions, and creams. As a surfactant, it reduces surface tension to lift away oils, dirt, and impurities during rinsing. Its emulsifying properties stabilize oil-in-water or water-in-oil mixtures, promoting uniform texture and preventing phase separation. It also acts as an opacifier by scattering light, giving formulations a smooth, creamy appearance that hides particles and enhances visual uniformity.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Opacifying agent
Makes a formula less transparent to create a creamy, opaque look; can also help visually mask suspended particles and improve aesthetic uniformity.
Surfactant
Lowers surface tension to enable cleansing, emulsifying, and foaming; central to shampoos, body washes, and many emulsions and micellar systems.
Cleansing agent
Removes dirt, oil, and impurities by lowering surface tension and forming micelles, enabling soils to be lifted and rinsed away from skin, hair, or teeth.
Emulsifying agent
Enables stable mixing of oil and water phases by forming an interfacial film, helping create lotions, creams, and cleansers with consistent texture.

Benefits

Supports gentle cleansing by aiding removal of surface impurities and excess oils.

Contributes to stable emulsions for consistent lotion and cream textures.

Enhances product appearance with opacity for a premium, uniform look.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Users seeking mild surfactants in daily cleansers and shampoos.
Those prone to Malassezia-related skin concerns like fungal acne.
Individuals preferring plant-derived ingredients in emulsions.
People with sensitivities to long-chain fatty acids.
People wanting non-comedogenic options in rinse-off products.
Individuals experiencing issues with oil-derived ingredients.

Safety Notes

  • Considered low hazard with minimal irritation potential in cosmetic use.
  • Non-comedogenic, suitable for acne-prone skin types.

Frequently Asked Questions about Arachidic Acid

What is arachidic acid derived from?

It comes naturally from plant oils like peanut and rapeseed, used in small amounts in cosmetics.

Is arachidic acid comedogenic?

No, it has a comedogenic rating of 0, making it unlikely to clog pores.

Can arachidic acid feed Malassezia?

It is flagged as a potential Malassezia feeding concern, so caution advised for related skin issues.