What Is Hair Porosity?
Hair porosity refers to your hair's ability to absorb and retain moisture. It's determined by the structure of the hair's outermost layer — the cuticle — and how tightly or loosely those cuticle scales lie. Understanding your porosity level is arguably the most useful piece of information for building a hair care routine that genuinely works.
There are three porosity levels: low, medium (normal), and high. Each requires a different approach to moisturising, conditioning, and product selection.
How to Test Your Hair Porosity at Home
The float test is the simplest method:
- Take a clean strand of hair (free of product) and drop it into a glass of room-temperature water.
- Wait 2–4 minutes and observe.
- Floats: Low porosity. Sinks slowly: Medium porosity. Sinks quickly: High porosity.
Note: this test isn't 100% definitive — also consider how your hair behaves with products (does it absorb them quickly or does product sit on top?).
Low Porosity Hair
Low porosity hair has tightly closed cuticles that resist moisture entry. Products tend to sit on top of the hair rather than absorbing in. Common signs include:
- Hair takes a long time to get fully wet in the shower
- Products build up easily, leaving hair feeling coated or heavy
- Colour takes a long time to process or doesn't take well
Best approach: Use lightweight, liquid-based products rather than thick butters or creams. Apply conditioner to warm, damp hair to help open the cuticle. Clarify regularly to remove buildup.
Medium (Normal) Porosity Hair
Medium porosity hair has a slightly raised cuticle that allows moisture in and holds it reasonably well. This is the "easiest" porosity to manage — most products work well, colour processes predictably, and moisture retention is balanced.
Best approach: Maintain what you have. Avoid excessive heat styling or chemical processing, which can shift hair towards high porosity over time. A weekly deep condition is sufficient.
High Porosity Hair
High porosity hair has open or damaged cuticles that absorb moisture quickly but also lose it just as fast. It's often a result of chemical processing, heat damage, or environmental factors, though it can also be genetic. Signs include:
- Hair gets wet and dries very quickly
- Often feels dry and frizzy despite regular conditioning
- Tangles easily and can feel rough to the touch
Best approach: Focus on sealing moisture in after hydrating. Layer products using the LOC (Liquid, Oil, Cream) or LCO method. Look for ingredients like shea butter, oils (especially heavier ones like castor or avocado), and protein treatments to help fill gaps in the cuticle.
Porosity and Protein Treatments
High porosity hair often benefits from protein treatments, which temporarily fill in the gaps in the cuticle. However, overusing protein can lead to brittle, snapping hair — known as protein overload. Balance protein treatments with deep moisture treatments to keep hair strong yet pliable.
Does Porosity Change Over Time?
Yes — chemical treatments, heat styling, UV exposure, and even hard water can raise the cuticle and increase porosity. This is why protecting your hair from unnecessary damage is so important. Using heat protectant, reducing bleaching frequency, and rinsing with cool water after conditioning can all help maintain a healthier porosity level.
Final Thoughts
Once you understand your porosity, product selection becomes far more intuitive. Instead of buying based on marketing claims, you can choose based on what your hair actually needs — and start seeing real results.