Porosity Without the Myths
A behaviour description, not a home lab test.
Last reviewed by the Hairavie editorial team on September 1, 2026.
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What porosity describes
Broadly, porosity refers to how readily water and small molecules move into and out of the hair fibre. Cuticle condition is a large part of that: intact, tightly layered scales slow exchange; lifted or eroded scales speed it up.
It is best treated as a description of behaviour you can observe, not a fixed number your hair carries.
About the float test
The strand-in-water test is not a clinical or scientific diagnostic. Results are influenced by product residue, sebum, surface tension and how the hair was dropped.
Hairavie estimates porosity behaviour from what your hair actually does — how quickly it wets, how long it takes to dry, whether products seem to sit on the surface — and always shows a confidence level.
Treat any porosity read as an estimate with error bars, including ours.
Damage and weathering change behaviour
Heat, chemical processing, UV and mechanical friction gradually wear the cuticle. Older hair near the ends has been through more of that history than hair near the scalp, so one head can behave differently along its length.
Why porosity is never the whole answer
Porosity can influence how a product feels and how long results last. It does not set an ideal formula weight on its own, and it does not tell you whether your hair needs protein.
In Hairavie, porosity informs routine guidance and a small, bounded relevance nudge. It is never a scored factor.
How Hairavie knows this
Hairavie cites peer-reviewed research, scientific reviews, reference textbooks, dermatology organisations and government health resources. Beauty blogs are never used as scientific authority.
- Reference textbookRobbins, C. R. (2012). Chemical and Physical Behavior of Human Hair (5th ed.). Springer
- Peer-reviewed studyBhushan, B. (2008). Nanoscale characterization of human hair and hair conditioners. Progress in Materials Science
- Scientific reviewGavazzoni Dias, M. F. R. (2015). Hair cosmetics: an overview. International Journal of Trichology
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