If you've ever wondered why some hair drinks up oil and stays soft while other hair feels coated and greasy, or why a product works wonders for a friend but does nothing for you, the answer is often porosity. It's one of the most useful things you can understand about your hair — and one of the easiest to test at home.
Here's what hair porosity is, how to test yours, and how to care for each type.
What is hair porosity?
Porosity describes how easily your hair absorbs and holds on to moisture. It comes down to the cuticle — the outer layer of overlapping scales on each strand.
- When the cuticle lies flat and tight, moisture struggles to get in or out.
- When the cuticle is raised or has gaps, moisture floods in easily — but escapes just as fast.
Porosity is partly genetic and partly the result of damage from colouring, heat and chemical processing, which lifts and weakens the cuticle over time.
The three porosity types
- Low porosity: the cuticle is tightly closed. Water beads on the surface, products sit on top rather than sinking in, and hair takes a long time to get wet and to dry. Prone to product build-up.
- Medium (normal) porosity: the cuticle is slightly open. Hair absorbs and retains moisture well, holds styles, and is generally the easiest to manage.
- High porosity: the cuticle is raised or damaged. Hair soaks up moisture instantly but loses it fast, often feels dry, frizzy and rough, and can tangle easily.
How to test your hair porosity
No single test is perfect, but together these give a good picture:
The float test. Drop a single clean, dry strand into a glass of water and wait a few minutes. If it floats, you likely have low porosity; if it sinks slowly, medium; if it sinks fast, high. (Treat this as a rough guide — product residue and oils can skew it.)
The slip-and-slide test. Run your fingers up a strand from tip to root. Smooth means lower porosity; bumpy or rough means a raised cuticle and higher porosity.
The spray test. Mist a small section with water. If it beads on top, low porosity; if it absorbs quickly, high; if it sits a moment then absorbs, medium.
How to care for your porosity type
Low porosity hair needs help letting moisture in:
- Use lightweight products that won't sit on the surface and build up.
- Apply treatments to slightly warm, damp hair — gentle heat helps open the cuticle.
- Clarify regularly to clear build-up. The vegan Clarifying range resets hair that feels coated.
High porosity hair needs help holding moisture in:
- Layer in rich moisture and seal it with a cream or oil.
- Use protein/repair care to help patch the gaps in the cuticle — the Restructurizing Hair Mask and Rebuild Replenishing range support weakened, porous hair.
- Deeply nourish with the vegan Dry Hair range — Nourishing Shampoo, Conditioner and Mask, with organic oats extract, illipé butter and coconut oil.
- Rinse with cool-ish water to help the cuticle lie flatter and seal moisture in.
Medium porosity hair is the easy middle ground — maintain it with balanced moisture and the occasional deep treatment, and avoid over-processing that would push it towards high porosity.
Frequently asked questions
Can you change your hair porosity? You can't change your genetic baseline, but you can improve high porosity caused by damage — protein and moisture care help, and reducing heat and chemical processing stops it getting worse.
Is high or low porosity worse? Neither is "bad" — they just need different care. High porosity needs moisture sealed in; low porosity needs help absorbing it in the first place.
How do I know if my hair is high porosity? It usually gets wet quickly, dries fast, feels dry or frizzy, soaks up product, and tangles easily — often a sign of colour or heat damage.
Does the float test really work? It's a popular rough guide, not a precise science. Oils and product residue can affect the result, so use it alongside the slip-and-slide and spray tests.
Once you know your porosity, the right products finally make sense. Nourish high-porosity hair with the vegan Dry Hair and Damaged Hair ranges, and reset low-porosity hair with Clarifying.