Understanding Hair Porosity Without a Float Test

What researchers can examine

Hair fibres have an outer cuticle and an inner cortex. Researchers use methods such as microscopy and contact-angle measurements to study structure and how surfaces interact with water. These methods ask specific questions under controlled conditions; an online quiz cannot reproduce them.

In one study of Mongolian hair samples, oxidative bleaching changed the surface and made it more wettable. Conditioning treatments changed some surface properties again. This supports considering treatment history and product coatings when interpreting water behaviour. It does not supply a universal home cutoff for low or high porosity.

Why we do not score a glass-of-water test

The familiar float test asks you to place a shed hair in water and classify it by whether it floats or sinks. The sources used for this guide do not validate that procedure as a diagnostic test for a person’s hair porosity. We therefore do not convert a floating strand into a confident low-porosity result.

A single shed fibre is also a very narrow sample of the hair you are trying to care for. The practical question is whether a routine works across your current lengths, including roots, older ends and any processed sections. A cup result does not answer that question.

Keep an observation log over three washes

Use your normal cleansing and conditioning routine for the first wash. Note how thoroughly you wet each section, the products and approximate amounts, whether you air dried or used a dryer, and when the roots and ends felt dry. Record the room or weather conditions in ordinary terms such as cool indoors or warm and humid.

Repeat without deliberately changing several products at once. This is a routine log, not a controlled experiment. Its value is finding repeatable inconveniences: a patch that is hard to saturate, a leave-on product that always feels coated, or ends that need attention while the rest feels comfortable.

• Before washing: What was already on the hair, including dry shampoo or oil?
• During washing: Did all sections become thoroughly wet?
• After drying: Where did the hair feel rough, coated, tangled or comfortable?
• Next morning: Was the result still manageable, and how much refresh work was needed?

Choose the next step from the problem you noticed

If products seem uneven, first compare application in smaller sections with the same formula. If a leave-on product feels excessive, compare a smaller amount on the next wash. If the ends remain difficult to manage, consider a leave-in designed for that use, applied where needed and according to its label.

Do not replace a rinse-out conditioner with a homemade leave-in mixture. The AAD distinguishes products intended to remain on the hair from those intended to be rinsed away. That distinction is more useful at the shelf than a porosity label alone.

Let uncertainty stay visible

“Wetting is slow, but the result varies with styling products” is an honest observation. “Low porosity, proven” would claim more than the observation supports. Our porosity tool helps organise these clues and suggests a next routine trial; it does not report a measured percentage or diagnose fibre damage.

Bleached lengths deserve their own note because laboratory microscopy has documented structural changes after excessive bleaching. The extent of those changes cannot be determined from your bleach history alone. For repeated breakage or a major change that persists despite gentle care, seek an in-person assessment instead of escalating through increasingly strong home treatments.

Record conditions alongside the result

Wetting, drying and the feel of a product describe different parts of the experience. In the linked laboratory work, bleaching and selected conditioner formulations changed the water-wetting properties of the hair surface. That is one reason a surface observation should not be treated as a permanent whole-head porosity label.

This is our suggested note format for ordinary wash days, not a validated test. For example, “dried more slowly after a larger leave-in amount on a humid day” contains two changing conditions. Repeat with one of those conditions held steady before deciding that the product is the cause. No need to wait for an ideal experiment to keep using a comfortable routine.

Sources for this section: Liu et al.: bleached hair, surface wetting and conditioning.