Let’s talk Porosity!
Porosity refers to how well your hair is able to absorb and hold moisture. It is affected by the flexible outer hair layer called the cuticle, which determines how easily moisture and oils pass in and out of your hair. For most, porosity is genetic, but it can also be affected by external factors such as exposure, heat treatments and chemical processing. Knowing your hair’s porosity can help you choose the right products to keep your hair well-moisturized, supple, strong and shiny.
DETERMINING HAIR’S POROSITY
There are two methods you can use to find out how porous your hair is.
- The Slip’n’Slide Test: Take a strand of hair and slide your fingers up the shaft (toward the scalp). If you feel little bumps along the way, this means that your cuticle is lifted and that you have high porosity. If your fingers slip smoothly, then you have low porosity hair.
- The Float Test: Take a couple of strands of hair from your comb or brush and drop them into a bowl of water. Let them sit for 2-4 minutes. If your hair floats, you have low porosity. If it sinks, you have high porosity.
Hair with low porosity has a tightly bound cuticle layer with overlapping scales that lay flat. This type of hair is usually considered healthy, and is often very shiny, especially when it’s dark in color. Low porosity hair repels moisture when you try to wet it and is hard to process since it resists penetration of chemicals.
Low porosity hair is also prone to build-up from protein-rich deep conditioning products, which can leave it feeling stiff and straw-like. Stick to protein-free, daily conditioners with humectants such as glycerin or honey. Use moderate heat with protein-free deep conditioning treatments to help open up the tightly bound cuticle.
Low porosity hair requires moisturizers rich in emollients such as shea butter, jojoba oil, coconut oil and mineral oil. It also benefits from humectant products, which attract and hold moisture to your hair. Choose lighter, liquid-based products such as hair milks that won’t sit on your hair and leave it oily or greasy.
Hair possessing average porosity will generally require the least amount of maintenance. It allows moisture to pass into the cortex as needed, but resists permitting too much water to penetrate. An occasional deep conditioning treatment with a protein-containing product will be of benefit, but proteins should not be included in the daily regimen.
High porosity is an unfortunate result of damage to the hair. Chemical processes, harsh treatment, and environmental exposure are all responsible for causing cumulative, irreversible damage to the cuticle layer. This damage creates gaps and holes in the surface of the hair shaft—essentially chinks in its armor. Hair with this type of uneven, pitted and rough surface is prone to damage from more and more sources, resulting in a cascade of effects that culminate in unmanageable and unlovely locks.
Hair with a great deal of porosity has been found to be capable of absorbing significantly higher amounts of water than hair or normal or low porosity (up to 55%, in contrast with 31.1% for healthy hair). Excessive absorption of water from the atmosphere causes frizz and tangling on humid days. Total immersion of high porosity hair during bathing, swimming, or shampooing can lead to significant breakage due to loss of elasticity from the sheer weight of the water absorbed. It also takes on color much more quickly and in higher concentrations than normal porosity hair when undergoing a chemical color process.
People with high porosity hair should use products with lots of moisturizers and emollients and also use anti-humectants in high heat and humidity climates in order to seal their cuticle against excessive absorption of moisture from the air. Protein treatments can also be very helpful for patching some of the holes in the hair, but one must follow up with moisturizing products in order to avoid a stiff texture. Rinsing with a slightly acidic rinse will help flatten and seal the cuticle. Some clear color applications have proteins in them than can patch the gaps in your hair also. Consult your professional hair stylist for more information about such products.