Low Porosity vs High Porosity Hair: How to Tell and What to Do

Porosity describes how easily moisture moves in and out of the hair shaft, and it explains more about why products work — or don't — than curl type alone. Two people with the same curl pattern can have completely different porosity, and completely different routines as a result.

The Float Test

Drop a clean, product-free strand of hair into a glass of room-temperature water. Hair that floats for several minutes is typically low porosity. Hair that sinks quickly is typically high porosity. It's not a perfect test, but it's a useful starting point.

Low Porosity Hair

The cuticle lies flat and tight, making it hard for moisture to get in — but also hard for it to escape once it does. Low porosity hair tends to resist water at first (it beads up rather than absorbing), takes a long time to dry, and gets weighed down easily by heavy products.

What works: applying products to damp, not soaking, hair; using heat (a warm towel, steamer, or hooded dryer) during deep conditioning to help the cuticle open; and avoiding heavy butters and oils that just sit on top of the strand.

High Porosity Hair

The cuticle is raised or has gaps — often from heat damage, chemical processing, or genetics — so moisture gets in fast but escapes just as fast. High porosity hair tends to dry quickly, tangle easily, and feel dry no matter how much product is used.

What works: richer creams and butters that seal moisture in; leave-ins with film-forming ingredients that help smooth the cuticle; and more frequent deep conditioning, since moisture doesn't stay put as long.

Why This Matters More Than Curl Type

A wash-and-go routine built for high porosity hair can leave low porosity hair looking greasy and weighed down within a day, and the reverse routine can leave high porosity hair dry within hours. If products never seem to work the way reviews say they should, porosity mismatch is usually why.

Related Reading

Chronic dryness despite a solid routine often traces back to a porosity mismatch — see the most common causes of curly hair dryness. And low porosity hair in particular is prone to product buildup, so knowing the signs of buildup is worth reading too.