Hair Porosity Explained
Hair porosity is your hair's ability to absorb and hold moisture, determined by how tightly the cuticle layer lies. It comes in three levels: low (cuticle flat, repels water), medium (balanced), and high (cuticle raised, absorbs and loses water fast). Here is how the three differ and how to find yours.
What Is Hair Porosity?
Hair porosity is how easily your hair takes in and holds onto moisture. It is governed by the cuticle, the shingle-like outer layer of each strand: when those shingles lie flat and tight, water struggles to get in or out (low porosity); when they are raised or have gaps, water rushes in and escapes just as fast (high porosity). Porosity is partly genetic and partly the result of damage from heat, bleaching, coloring and friction. It matters because it decides which products and techniques actually work on your hair, regardless of your curl pattern.
What Are the Three Porosity Levels?
There are three levels. Low porosity has a tight cuticle that repels water: hair is slow to wet, slow to dry, and prone to product sitting on top as buildup. High porosity has a raised or damaged cuticle: hair soaks up water instantly, dries fast, and struggles to stay moisturized, often feeling dry or frizzy. Medium porosity sits in the middle, with a cuticle loose enough to let moisture in but tight enough to hold it, which is why it is generally the easiest to manage.
How Do You Find Your Hair Porosity?
Three signals identify porosity. The float test: a clean dry strand dropped in water floats if low porosity, sinks if high. The wet-and-dry test: how fast your hair absorbs water and how long it takes to dry. And the product test: whether products sit on top (low) or vanish and leave hair still thirsty (high). Because any single test can mislead, the free porosity test on this site combines all three signals into one result in about a minute.
Why Does Porosity Matter With Hair Type?
Your hair type tells you the shape of your hair; your porosity tells you how it handles moisture. They are independent, so a 3B with low porosity and a 3B with high porosity need genuinely different routines, even though they share a curl pattern. This is the missing half of most hair advice: combining your type and your porosity is what turns a generic routine into one that actually fits. Take both the hair type quiz and the porosity test to get the full picture.
The three porosity levels
- Low Porosity HairLow porosity hair has a tight, flat cuticle that repels water: it is slow to get wet, slow to dry, and products tend to sit on top rather than absorbing.
- High Porosity HairHigh porosity hair has a raised or damaged cuticle with gaps: it absorbs water and products instantly but loses moisture just as fast, so it often feels dry, frizzy or thirsty.
- Medium Porosity HairMedium porosity hair has a balanced cuticle that lets moisture in and holds onto it well, making it the easiest porosity to care for.
Not sure which one you are?
Take the free, 1-minute porosity test to find out.
Take the porosity testFrequently Asked Questions
- What are the three types of hair porosity?
- Low porosity (tight cuticle, repels water), medium porosity (balanced), and high porosity (raised or damaged cuticle, absorbs and loses moisture fast).
- How is porosity different from hair type?
- Hair type is your curl pattern, from 1A to 4C. Porosity is how your hair absorbs and holds moisture. They are independent: any type can have any porosity.
- What is the most common hair porosity?
- Medium porosity is generally considered the most common and the easiest to care for, though high porosity is widespread too, especially among people who color or heat-style their hair.
- How do I know if I have low or high porosity?
- Low-porosity hair is slow to get wet and slow to dry, with products sitting on top. High-porosity hair wets and dries fast and drinks up product while still feeling dry. The free test settles it.