How to Find Your Hair Porosity (And Why It Matters More Than Type)

Most people know their curl type. Far fewer know their porosity — and porosity is the one that decides whether a product works.

Curl type describes what your hair looks like. Porosity describes how it behaves: how easily water gets in, and how long it stays. Two people can both have 4C hair and need opposite routines. That’s why a product with hundreds of glowing reviews can do nothing for you.

Here’s how to find yours without buying anything.

What porosity actually is

Your hair is covered in cuticle scales that overlap like roof tiles.

• Low porosity — scales lie flat and tight. Water beads on the surface. Hard to wet, hard to product, but holds moisture well once it’s in.
• Medium porosity — scales are slightly open. Absorbs and retains reasonably. The easy one.
• High porosity — scales are raised or damaged. Soaks up water instantly and loses it just as fast. Often the result of colour, heat, or relaxers, though some people are born this way.

Note that high porosity isn’t automatically “damaged hair,” and low porosity isn’t “healthy hair.” They’re just different behaviours.

Test 1: The strand-in-water test

The famous one. It’s directional, not definitive.

1. Take a shed strand from your brush — not one you pull out
2. It must be clean and product-free. Oils and butters make anything float.
3. Drop it in a glass of room-temperature water
4. Wait 4 minutes

Floats → likely low porosity. Sits mid-glass → medium. Sinks → likely high.

Why it’s unreliable: surface tension holds light strands up regardless of porosity, and product residue skews everything. Treat this as one data point, not a verdict. If it disagrees with the next two tests, trust the next two.

Test 2: How your hair behaves on wash day

This is the most reliable test, and it’s free.

Low porosity signs:

• Water beads and rolls off before your hair is properly wet
• Takes forever to saturate in the shower
• Products sit on top and your hair feels coated, not moisturised
• Buildup happens fast
• Takes a long time to air dry
• Heat makes a noticeable difference to deep conditioning

High porosity signs:

• Soaks up water almost instantly
• Air dries fast
• Feels dry again within a day of moisturising
• Drinks product — you always seem to need more
• Tangles easily, feels rough when you run fingers up the strand
• Frizzes hard in humidity

Medium porosity signs:

• Wets and dries in a reasonable time
• Holds a style for a few days
• Most products work fine

Test 3: The stretch test

Wet a shed strand and pull gently.

• Stretches a lot, feels gummy, doesn’t spring back → high porosity, often with too much moisture and not enough protein
• Snaps quickly with little stretch → needs moisture
• Stretches slightly and returns → balanced

This one tells you about your protein–moisture balance, which is the other half of the picture.

What each result means for your routine

Low porosity

Your problem is getting moisture in.

• Use heat. A cap under a warm towel, a heat cap, or a hooded dryer. This is the single biggest lever you have and it’s free.
• Go lighter. Thin liquids, milks, and aloe-based leave-ins. Heavy butters and thick oils sit on the surface.
• Apply to soaking wet hair, not damp.
• Clarify monthly. Buildup is your recurring problem, not dryness.
• Be careful with protein. A flat cuticle has fewer gaps to fill, so protein sits on top and stiffens the strand.

High porosity

Your problem is keeping moisture in.

• Seal. Layer a cream, then an oil or butter on top to slow the water leaving.
• LOC or LCO method — liquid, oil, cream in one order or the other. Try both, keep whichever holds longer.
• Protein helps here, in moderation. It temporarily fills the gaps.
• Cool rinse at the end of wash day to help the cuticle lie flatter.
• Satin at night, always. Cotton pulls moisture straight out.

Medium porosity

Maintain rather than correct. Deep condition regularly, don’t overload on protein, and don’t fix what isn’t broken.

Porosity can change

It isn’t fixed for life. Colour, bleach, relaxers, and repeated heat all raise porosity by damaging the cuticle. Hair can also be different porosities along the same strand — high at the ends where it’s older and more worn, lower at the roots. If your ends behave differently from your roots, that’s why, and it’s normal.

Retest after any chemical service, or if a routine that worked stops working.

Quick reference

Once you know your porosity, you can read a label and predict whether something will work. Run any product through our ingredient checker to see what’s actually in it — and see the low porosity picks if that’s where you landed.