Hair Porosity Test: Why Your Expensive Routine Isn't Working

You can buy the right products for your curl type and still get terrible results — because curl type isn't the whole story. Porosity is the variable most routines miss, and it's why two people with identical curls can have completely opposite product needs.

This guide covers the porosity test, what each level means, and how to fix the routine for each one.

The porosity test (3 minutes)

You'll need a clean strand of hair (pulled from a hairbrush, not freshly shed) and a glass of room-temperature water.

1. Drop the strand into the glass
2. Wait 3 minutes
3. Don't poke it

After 3 minutes, look at where the strand sits.

• Floats on top = Low porosity
• Suspended in the middle = Normal porosity
• Sunk to the bottom = High porosity

That's it. The test isn't perfect (one strand isn't fully representative), but it's directionally accurate.

What porosity actually is

Each hair shaft has an outer cuticle layer made of overlapping scales. How tightly those scales close determines how easily water and product enter and leave the strand.

• Low porosity: Scales tightly closed. Water beads on the surface; products sit on top.
• Normal porosity: Scales slightly open. Balanced absorption and retention.
• High porosity: Scales raised or damaged. Water enters fast and leaves fast.

Hair is porous in two directions: in (absorbing) and out (releasing). Low-porosity hair is hard to wet AND hard to dry. High-porosity hair drinks water but loses it within hours.

Low porosity — the routine

Symptoms:

• Water rolls off your hair when you shampoo
• Products sit on top, never absorb
• Conditioner needs to be left in for 30+ minutes
• Hair takes forever to dry but feels stiff
• Common in fine straight (1A-1B) and unprocessed natural hair

Routine fix:

1. Use heat to open the cuticle. Apply conditioner, cover with a shower cap, and use heat (warm towel, hooded dryer, or just a warm shower) for 10-15 minutes before rinsing. Heat opens the scales temporarily.

2. Avoid heavy butters. Shea butter, coconut oil, castor oil — they sit on top of low-porosity hair and never absorb. They make hair feel coated, not moisturized.

3. Use water-based products. Hyaluronic acid serums, water-based leave-ins, glycerin-rich conditioners. These are small enough molecules to enter the closed cuticle.

4. Skip protein treatments. Low-porosity hair is generally protein-strong. Adding more makes it stiff and prone to breakage.

5. Steam treatments (DIY: cover with a plastic cap and warm towel) are the magic wand here.

Normal porosity — the routine

Symptoms:

• Water absorbs evenly when wet
• Hair holds curl pattern well
• Color treatments take cleanly
• Products work as labeled

Routine fix: Lucky. Your routine is whatever works for your curl type. Don't fix what isn't broken. The biggest risk for normal-porosity hair is over-treating — heavy oils when you don't need them, protein treatments when your hair is already strong.

High porosity — the routine

Symptoms:

• Hair absorbs water instantly when shampooing
• Hair feels rough or dry within hours of moisturizing
• Color fades fast
• Hair tangles easily and breaks
• Often the result of damage (heat, color, chemical processing) but can be genetic

Routine fix:

1. Seal in moisture. Use the LOC method: Leave-in (water), Oil, Cream. The oil layer is the key — without it, all your moisture evaporates.

2. Heavy butters and oils work here. Shea butter, coconut oil, jojoba — they fill in the raised cuticle scales and seal moisture.

3. Use protein treatments. High-porosity hair is often protein-deficient — that's part of why the cuticle is open. Once a month, do a light protein treatment (rice water, hydrolyzed wheat protein).

4. Acidic rinses help. Apple cider vinegar diluted (1 tbsp in 2 cups water) closes the cuticle temporarily. Rinse hair with this after conditioning, then rinse with cool water.

5. Cool water rinses. Cold water closes scales. Always end your shower with a cold rinse.

6. Avoid sulfates. They strip the natural oils your high-porosity hair needs to stay sealed.

Mixed porosity is real

Lots of people have one porosity at the roots (often low, since unprocessed) and another at the ends (often high, from damage). This is called mixed porosity.

Solution: Treat the ends like high porosity. Use protein and seal aggressively. Treat the roots more lightly.

What if the test was inconclusive?

Some signs to look for:

• Floats indefinitely (>5 minutes): Definitely low.
• Sinks slowly (1-3 min): Likely normal.
• Sinks within 1 min: Likely high.

If multiple strands give different answers, you have mixed porosity. The longer hair (older, more damaged) will be higher porosity than fresh growth.

The single biggest takeaway

If your routine isn't working, porosity is the variable most likely to be wrong. Hair type tells you the shape (curl, wave); porosity tells you what enters and stays.

Get porosity right and the same products work better. Most "I've tried everything" cases are someone using high-porosity products on low-porosity hair, or vice versa.