Fatty acids are used as oily bases and emulsifiers in skincare formulas.

There are a bunch of fatty acids you’ll find in carrier oils, the two you should focus on to determine the feel of an oil are oleic acid and linoleic acid.

Oleic acid makes oils feel richer and heavier, so they’re more occlusive. A small list of oils high in oleic acid include:

• olive oil
• safflower oil
• almond oil
• avocado oil
• and others

Linoleic acid makes oils feel lighter and thinner (relatively speaking). It can also make an oil feel more astringent and “dry”. These are perfect for combination – oily skin types. A small list of oils high in linoleic acid include:

• passion fruit oil/maracuja
• sesame seed oil
• seabuckthorn oil
• grapeseed oil (astringent)
• castor oil (astringent)
• and others

An interesting read on fatty acids in wound repair & prevention: The usefulness of topical application of essential fatty acids (EFA) to prevent pressure ulcers. Source