This test is based on the fact that damaged hair has less of the protective lipid layer, 18-MEA in the F-Layer(external layer) of the cuticles. 18-MEA is hydrophobic and will tend to repel any water droplets. In virgin hair, the repulsion is highest while damaged hair is more hydrophilic (loves water) and will draw in the water quite readily. Here’s how we can crudely test and determine the hair’s damage level.
Note that this test cannot distinguish the levels of porosity between virgin hair samples. All virgin hair will have a significant amount of 18-MEA and will create the same net result. Many have suggested using the float test for determining porosity in virgin hair. But, like I mentioned before, this test is heavily flawed. The only conclusive way to know the level of porosity in virgin hair could be through gas chromatography as demonstrated by this study.
How to determine your hair damage level
Before you start, choose a day where you will not need to step out. The drying process and re-shampooing can take a while. You will need a clear shampoo such as the sulfate-free Free and Clear shampoo, a blow dryer (optional), and spray bottle.
- Shampoo your hair with the clear shampoo. Avoid any creamy ones that can deposit conditioning ingredients. Shampoo a few times as necessary to properly rid the hair of any resilient coating.
- Do not condition. And therefore do not detangle the hair as well to avoid any breakage at the knots.
- Either air dry or rough dry with a blow dryer. When using a blow dryer, let the hair cool down for at least an hour (longer the better) before doing the test. Heat causes the hair to swell. This might skew your test. Letting the hair re-calibrate itself is important.
- Once you are ready to test, use the spray bottle and spritz a few times on the hair. You should create a fine mist around the hair. Observe how the water droplets behave on the hair. For short hair, this test is easier done with the help of someone to spray or even take pictures of the water droplets on hair.
- Once you are done, re-shampoo and condition as you normally would with your products. And style as needed.
Interpretation of the droplets behavior
Each damage level will affect the water droplet differently. This test is actually looking at the wettability of hair.
On virgin hair: the water will bead up and can easily be seen rolling off the hair. The lipids prevent the water from wetting the hair. You can clearly see that the droplets don’t seem to absorb.
On mildly damaged hair: the droplets should look semi-oval to flat but this might be hard to distinguish. Typically, the water droplets sit on the surface but they slowly absorb into the hair. The time frame will depend on how much 18-MEA is present.
On damaged hair: the water absorbs right way. Beading of the water droplets is not seen. The lack of 18-MEA makes the hair hydrophilic.
You will find that the results can also be different at the roots versus the ends of the hair because the ends have more damage.