How do I know my hair porosity?

Hair porosity refers to your hair's ability to absorb and retain moisture based on the condition and behavior of its cuticle layer. You can assess your porosity through a combination of the float test, the slip test on wet hair, and observation of how your hair responds to water and products. Low porosity hair resists water absorption and takes a long time to fully wet. High porosity hair absorbs water quickly but loses it just as fast. Normal porosity hair wets easily and holds moisture for a reasonable period.

The cuticle is the outermost layer of the hair shaft, made up of overlapping scale-like cells. When these scales lie flat and tight, water struggles to enter — this is low porosity. When the scales are raised, damaged, or widely spaced, water enters freely but escapes just as readily — this is high porosity. Understanding your porosity profile is foundational to selecting products, structuring your routine, and troubleshooting moisture issues. Many women with textured hair have high porosity as a result of chemical processing, heat damage, or the natural geometry of tightly coiled strands, which creates more points of cuticle lift along the spiral. Porosity is not a fixed trait — it can change along the length of a single strand, from root to tip, and shift over time with damage or improved hair health.

• High porosity from chemical relaxers, color treatments, or keratin processing that permanently lift or damage the cuticle
• High porosity from chronic heat use without thermal protection, which causes cuticle fracturing
• Low porosity is often genetic and more common in hair that has never been chemically processed
• Mixed porosity along a single strand is common when new growth is healthy but older lengths have accumulated damage
• Hard water mineral deposits on the cuticle can mimic low porosity symptoms by creating a coating that blocks moisture entry
• Product buildup can coat the cuticle and cause high porosity hair to behave as though it is low porosity

1. Perform the float test: place a clean, shed strand in a glass of room-temperature water and observe for 2–4 minutes. Sinking quickly suggests high porosity; floating at the surface suggests low porosity.
2. Observe how your hair responds to water in the shower — does it bead and resist wetting, or absorb immediately? Resistant wetting points to low porosity.
3. Notice how long your hair takes to air dry — high porosity hair dries quickly, low porosity hair stays wet for hours.
4. For low porosity hair: apply products to damp hair, use lightweight water-based formulas, and apply gentle heat with a hooded dryer or steam cap to help products penetrate.
5. For high porosity hair: focus on protein treatments to temporarily fill cuticle gaps, use heavier creams and butters to seal, and apply cold water rinses after conditioning to encourage cuticle closure.
6. Use the Hair Porosity Test tool to get a structured assessment based on your specific observations and hair history.