You may have heard that two people can use the same shampoo and conditioner and get completely different results. One person’s hair looks soft and shiny, while the other’s feels dry or weighed down. A big part of the explanation is hair porosity, a concept that stylists and hair care educators use to describe how easily hair absorbs and keeps moisture. Once you know your hair’s porosity, choosing products and routines becomes much less of a guessing game. This guide explains the basics in simple terms.
What is hair porosity?
Each strand of hair is covered by an outer layer called the cuticle, made of tiny overlapping scales, a bit like roof tiles. When these scales lie flat and close together, the hair is smooth and water has a harder time getting in. When they are raised or separated, the hair absorbs water quickly but also loses it quickly. Porosity describes this behavior: how open or closed the cuticle is, and therefore how well the hair takes in and holds onto water and products.
Porosity can be partly genetic, but it also changes with what you do to your hair. Bleaching, coloring, frequent heat styling, harsh brushing and sun exposure can all lift the cuticle over time, making hair more porous than it was naturally.
The three types of porosity
| Type | Cuticle | How it behaves |
|---|---|---|
| Low porosity | Tightly closed | Resists water, products sit on top, slow to wet and slow to dry |
| Medium porosity | Slightly open | Absorbs and holds moisture well, easy to style |
| High porosity | Raised or gaps | Absorbs fast but loses moisture fast, dries quickly, tends to frizz |
Low porosity hair
With low porosity, the cuticle lies very flat. Water beads up on the hair, it takes a long time to get fully wet and even longer to dry. Products, especially thick creams and oils, tend to sit on the surface instead of soaking in, which can leave the hair feeling coated or heavy. Many people with this hair type notice build-up quickly.
Care tips for low porosity usually include:
- Choose lightweight products, such as light lotions, gels and water-based conditioners.
- Apply products on damp, warm hair, since gentle warmth helps the cuticle open a little.
- Use a clarifying shampoo from time to time to remove build-up.
- Go easy on heavy butters and rich oils, which can weigh the hair down.
Medium porosity hair
Medium, or normal, porosity is considered the balanced middle ground. The cuticle is open just enough to let moisture in and keep it there. Hair tends to hold styles well, shines naturally and reacts predictably to products. That does not mean it needs no care: damage from coloring, heat or friction can gradually shift it toward high porosity, so a gentle routine and regular conditioning are still important.
High porosity hair
High porosity hair has a cuticle that is raised, cracked or naturally more open. Water enters easily, so the hair wets in seconds, but it also escapes easily, so the hair dries fast and often feels dry, rough or frizzy. This type is common in hair that has been chemically treated or heat styled often, though some people have it naturally.
Care tips for high porosity usually include:
- Use rich, moisturizing conditioners and deep conditioning treatments regularly.
- Seal in moisture with creams, butters or oils after hydrating the hair.
- Rinse with cooler water at the end of washing, which can help the hair feel smoother.
- Protect the hair from heat and sun, and reduce harsh chemical treatments when possible.
- Consider protein-based or bond-repair treatments as advised by a professional.
How to check your porosity at home
You do not need special equipment to get a rough idea of your hair’s porosity. These simple observations are not laboratory tests, but they offer useful clues:
- Watch how it behaves in the shower. If water beads up and the hair takes a long time to soak, porosity is probably low. If it is soaked almost instantly, it may be high.
- Notice how products behave. Products that sit on the surface point to low porosity. Hair that seems to drink products and feel dry again soon after suggests high porosity.
- Check drying time. Very slow drying often goes with low porosity, and very fast drying with high porosity.
- Try the spray test. Spray a small section with water and watch: beading suggests low porosity, quick absorption suggests higher porosity.
You may also have heard of the glass-of-water test, in which a clean strand is dropped in water to see whether it floats or sinks. It is popular online, but it is not a reliable measure, since factors like oils and product residue can affect the result. Treat it as a curiosity, not a diagnosis.
Porosity is not the same as hair type
It is easy to mix up porosity with curl pattern, thickness or oiliness. These are separate characteristics. Straight, wavy, curly and coily hair can each have low, medium or high porosity, and a person can even have different porosity in different areas, since ends are usually older and more worn than roots. The best routine considers several factors together: curl pattern, strand thickness, scalp condition, treatments and porosity.
Conclusion
Knowing your hair’s porosity helps you understand why certain products work wonders and others fall flat. Low porosity usually calls for light products and gentle warmth, medium porosity benefits from consistent, balanced care, and high porosity needs extra moisture, sealing and protection. If you enjoy learning how hair behaves and want to turn that knowledge into a skill or a career, the hair care and aesthetics courses at Cursa offer a friendly place to start.
