Encyclopedia · oil or butter
Avocado oil
A rich oleic-acid oil common in deep conditioners, with no hair-fibre or clinical hair studies found.
What it is
Oil pressed from avocado fruit pulp, high in oleic acid. It is a cosmetic ingredient often used in masks and leave-ins.
How it works
We found no hair-specific mechanism study. By composition it behaves like other oleic oils (see olive oil). The Procter & Gamble penetration paper tested pure triolein, not avocado oil itself. Marsh 2024
What the studies show
- Pure triolein penetrated the cement between hair cells, but avocado oil was not tested. Marsh 2024
- No clinical or hair-fibre study of avocado oil was found, so all benefit claims are extrapolations (see oils and hair).
How it's used in studies
Unstudied for hair.
Side effects and safety
Low risk is expected, but we found no hair-specific safety data.
Bottom line
A moisturising-feeling emollient for thick or dry hair, with no evidence of special benefit. We are very unsure it does more than other oils.
Studies 1
Marsh JM et al. Penetration of oils into hair. Int J Cosmet Sci. 2024
Tested: pure plant triglyceride oils including coconut, Camellia oleifera and safflower
Result: Several plant oils entered the hair's lipid-rich cement and improved single-fibre fatigue strength; shorter and unsaturated chains penetrated better.
Read the study ↗Related
- Olive oilA traditional hair oil whose only supporting hair data is that its film thinned on hair like coconut oil did, suggesting some absorption.
- Shea butterA heavy plant butter widely used on coily hair, with no fibre-science data behind it.
- Oils and hairOils coat hair and some enter it, which can cut damage from washing, but they do not repair split ends or add moisture.