How to Tell If You Have Low Porosity Hair

You likely have low porosity hair if water beads on it and takes forever to soak in, products sit on top and leave a white film, and your hair takes hours to air dry. The glass of water float test that everybody posts does not reliably tell you anything, because a clean strand floats on surface tension no matter what its porosity is.

I made a video about this and it went further than anything else I have ever posted, which told me how many people are quietly frustrated and do not know why.

What porosity actually means

Porosity is how easily water gets into and out of your hair. That is it. It is not about how thick your hair is, how curly it is, or how strong it is.

The outside of every strand is covered in overlapping scales called the cuticle, like shingles on a roof. On low porosity hair those shingles lie very flat and tight. Water has a hard time getting past them, so your hair resists getting wet. Once water is finally in there, those same tight shingles hold it in, which is why low porosity hair holds moisture well once you get it.

Low porosity is usually genetic. High porosity is usually earned, through color, heat, or years of wear.

Three signs that actually work

1. Water beads on your dry hair before it soaks in

Stand in the shower and pay attention to the first thirty seconds. If water rolls off and you have to work it in before your hair feels properly wet, that is a tight cuticle doing exactly what a tight cuticle does. This is the single most reliable sign.

2. Products sit on top and go white

If your leave in leaves a white cast, or your hair feels coated and greasy at the surface while still feeling dry underneath, the product is not getting in. Low porosity hair is picky about heavy creams and butters for this reason.

3. It takes forever to dry

Water that had a hard time getting in has a hard time getting out. If a wash and go takes most of a day to dry, or your hair is still damp at the roots at bedtime, that is a strong sign.

Why the float test does not work

The test says to drop a clean strand in a glass of water and see whether it sinks or floats. The problem is surface tension. A dry strand of hair sits on the surface of still water almost regardless of porosity, and whether it eventually sinks has more to do with how much product residue is on it, whether you disturbed the water, and how long you waited than with your cuticle.

Try it three times and you will often get three answers. That is not a test. What is on your head every wash day is better evidence than a glass of water.

What changes once you know

Use warmth to open the cuticle

Heat lifts those flat scales enough to let water and product in. Apply deep conditioners and oil treatments to hair that is warm and wet, and put a cap on for twenty minutes. A warm towel does the same thing. This one change makes more difference than any product swap.

Go lighter with oils

Heavy butters and thick oils like raw shea or a lot of castor tend to sit on the surface of low porosity hair. Lighter oils spread and absorb instead. Grapeseed, jojoba, and avocado are the ones that work. Jojoba in particular is structurally close to your scalp's own sebum, which is part of why it does not feel like a coating.

Our oils are built on that lighter base on purpose, because low porosity is extremely common in type 4 hair and most of what is marketed to type 4 hair is far too heavy for it. Everything we make that suits a tight cuticle is gathered in one place, the low porosity hair collection.

Water first, always

Oil does not moisturize. It slows down how fast water leaves. If you put oil on dry low porosity hair, you have sealed dryness in and locked water out. Wet or damp hair first, product second.

Clarify more than you think you need to

Buildup is the low porosity tax. Product sits on the surface, and the next wash does not fully remove it, and after a month your hair stops responding to anything. A clarifying wash every four to six weeks resets it.

Can you be low porosity in some places and not others

Yes, and it is common. The hair at your crown, where it gets the most sun, and your ends, which are the oldest hair on your head, are often more porous than the hair underneath at the nape. Treat your ends like they are more porous than the rest, because they are.

The short version

• Water beading on dry hair is the most reliable sign.
• The float test is unreliable and you should stop worrying about it.
• Use warmth to get moisture in, and light oils rather than heavy butters.
• Water first, oil second, never oil onto dry hair.
• Clarify every four to six weeks or buildup will undo everything.

If you want the light oils described here, start with the low porosity hair products, or go straight to the scalp oils if your scalp is the part that needs help.