Forget Curl Type. Let’s Talk Porosity.
You probably know whether your hair is 3C, 4A, 4B, or somewhere in between. But do you know how your hair handles water?
Curl type describes the shape of your hair and the twists, curls, or coils it makes as it grows. Porosity tells us something different. It helps us understand how your hair interacts with water.
That can tell us a lot about hair health, product choices, product layering, and even how we style our hair.
Your curl type tells us what your hair looks like. Porosity can tell us more about how your hair behaves.
And when you are trying to build a hair routine that actually works, that information matters.
What Is Hair Porosity and Why Does It Matter?
Hair porosity describes how easily your hair takes in and interacts with water.
The outside of each hair strand is called the cuticle. Think of it like shingles on a roof. These small, overlapping layers help protect the inside of the hair strand. The condition of your hair affects how easily it interacts with water.
Hair porosity is usually described as low, medium, or high.
Low porosity: Water has a harder time getting into the hair and may take longer to leave. You may notice water sitting on your hair before soaking in, longer drying times, or products feeling like they are sitting on top of your hair.
Medium porosity: Water can move in and out of the hair without either extreme. Your hair may get wet fairly easily, hold onto water well, and respond well to your normal routine.
High porosity: Water can enter the hair more easily, but the hair may also lose water more easily. Damage from things like bleach, chemical treatments, heat, UV exposure, and everyday wear can increase hair porosity over time.
And here's something important: you can have more than one porosity on the same head of hair.
Your ends are older than the hair closest to your scalp. They have been washed, brushed, styled, exposed to the sun, and possibly colored or heat-styled many more times. Your ends may behave differently from your roots, and one section of your hair may behave differently from another.
This is one reason why, in my opinion, porosity can be more useful than curl typing when building a hair care routine.
Knowing that someone has 4A hair tells us what their curls look like. But does it tell us how quickly their hair gets wet? Whether their ends are damaged? How long their hair stays wet? Whether products tend to sit on top of it?
Not really.
Two women can both have 4A hair and need completely different routines.
Your curl type tells you the shape of your hair. Your porosity helps tell you how your hair behaves.
Curl typing isn't useless. It's just one piece of the puzzle, and we have put a lot of weight on it when choosing products and routines.
It may be time to start asking, “How does my hair actually behave?”
We're Retiring the Float Test. Observe Your Next Wash Day.
You have probably seen the porosity test where you take a loose strand of hair and drop it into a glass of water.
If it floats, the internet says you have low-porosity hair. If it sinks, you have high-porosity hair.
We're retiring that one.
A single hair floating or sinking in a glass does not give us enough information about how all of the hair on your head interacts with water. Things like oil, product buildup, and the surface tension of the water can also affect what happens to that strand.
Instead, I want you to observe the hair that is still attached to your head.
Welcome to the FLAIR Wash Day Porosity Check.
Pick a wash day when you have nowhere to go. A long weekend is even better. Give yourself enough time to let your hair do its thing without rushing to style it.
Here's what to do:
Shampoo your hair well.
Condition and rinse.
Apply a lightweight leave-in to soaking-wet hair.
Gently squeeze out the extra water.
Skip your gel, oil, mousse, butter, and heavier styling products for this wash day.
Start your timer and let your hair air-dry.
No blow dryer. No diffuser. No sitting directly in front of a fan.
Then pay attention.
Actually, journal it.
Ask yourself:
How long did it take for my hair to become fully wet in the shower?
Did water bead up or sit on my hair before soaking in?
How long did my hair take to air-dry?
Which sections dried first?
Did my ends dry faster than my roots?
Did some sections stay wet much longer than others?
Did any damaged or color-treated sections behave differently?
I know we love a good chart that tells us exactly what we have, but there is no perfect number of hours that proves your hair is low, medium, or high porosity.
Your hair density, length, strand thickness, the amount of water in your hair, room temperature, humidity, airflow, and even how much leave-in you use can affect your drying time.
So don't focus on one magic number.
Look for patterns.
Slow to get fully wet + stays wet for a long time may point toward lower-porosity behavior.
Gets wet easily + seems to lose that water quickly may point toward higher-porosity behavior.
Somewhere comfortably between the two may point toward medium-porosity behavior.
For an even better picture, repeat the FLAIR Wash Day Porosity Check for your next 2–3 wash days.
Try to keep the routine and products similar each time. Then compare your notes.
You are not trying to pass a porosity test. You are learning how your hair behaves.
What Does Your Porosity Mean for Your Routine?
Okay, now what?
Knowing your porosity is only useful if you know what to do with that information.
Lower Porosity Hair
Focus on getting water into your hair without piling on unnecessary products. Lighter products and fewer layers may work better, and regular cleansing can help prevent buildup. Gentle warmth while deep conditioning may also help your treatment work more effectively.
Try: lightweight leave-ins, styling milks, mousses, foams, gels, and lightweight oils or serums.
Remember, moisture comes from water, not more product. Your products help condition and protect your hair, support your style, and help manage how your hair interacts with water.
Medium Porosity Hair
If your routine is working, don't create a problem that isn't there. Keep your hair conditioned, cleanse regularly, and protect it from unnecessary damage.
Try: leave-ins, styling creams, mousses, gels, and deep conditioners as needed.
You do not need to fix hair that is doing just fine.
Higher Porosity Hair
Conditioning and protection become especially important. Look for products that condition, coat the hair, reduce friction, and improve manageability. Be gentle when detangling and limit additional damage when possible.
Try: deep conditioners, leave-ins, creams, styling butters, gels or custards, and serums or oils.
And remember, high porosity does not automatically mean you need heavy products. Higher porosity isn't automatically "bad hair." It simply gives you information about what your hair may need.
FLAIR's Takeaway: Learn Your Hair, Not Just Your Hair Type
Your hair is constantly giving you information. You just have to learn how to read it.
Your porosity is not another label you need to obsess over. It is a tool that can help you better understand what your hair needs right now.
And if you're still thinking, "Okay...but what does MY hair need?"
That's exactly where FLAIR Beauty+'s Hair Routine Concierge comes in.
We look beyond curl type to help you understand your hair, your current routine, your styling habits, and your goals, then build a routine that makes sense for you.
Because the goal isn't to collect more hair labels.
The goal is to know your hair.
