Turns Out, Your Hair Porosity Is Just as Important When Shampoo Shopping as Type and Colour
Your guide to low and high porosity strands
We select products for our hair type all the time—whether our priorities are shine, curls, coils, or breakage, but as it turns out, there's another thing we should consider before browsing the beauty aisles.
Speak to any hairstylist, and they'll likely espouse the virtues of knowing your hair porosity—but what does the term refer to? "It's used to explain how effectively the hair fibre absorbs and retains water, moisture products," Dr Sidra Khan, Glasgow-based consultant dermatologist, tells Marie Claire UK. This affects how well oil and moisture pass in and out of the outermost layer of your hair: the cuticle. As such, your porosity determines how well your hair is able to maintain hydration and nourishment.
As the dermatologist notes, it's very helpful to know your porosity, particularly for textured hair, as it guides smarter product and technique choices. "Scalp health, hair density, curl pattern, styling habits and overall health matter too, but I see porosity as a useful framework, not a strict rulebook. It's best assessed by observing how hair behaves over time rather than relying on one-off tests."
It's important to note that porosity is partly genetic, particularly in textured hair, where fibre curvature can affect cuticle alignment. It can also be altered by heat styling, chemical treatments, UV exposure and mechanical stress. Get the full breakdown ahead.
High Porosity vs Low Porosity Hair
"High porosity hair absorbs moisture quickly but loses it just as easily, often feeling dry, frizzy or fragile. In textured and tightly coiled hair, this can reflect natural fibre shape rather than damage," explains the expert.
On the other hand, low porosity hair has a tightly packed cuticle that resists water and product absorption, but once hydrated, tends to retain moisture well.
As a general rule, low porosity is usually inherited, while high porosity is more likely to develop over time due to cumulative damage.
The K18 Biomimetic Hairscience Peptide Prep Detox Shampoo is designed to deeply cleanse and remove 99% of product buildup, 95% of sebum, and 76% of copper in one wash, without stripping, making it ideal for dry, damaged or chemically processed strands.
K18's Hair Leave-In Molecular Repair Hair Mask specifically targets damage from bleach, colour, chemicals and heat, while using a patented peptide to repair broken polypeptide chains at the molecular level. For damaged, high porosity hair, this is ideal as it works inside the hair shaft to rebuild structure, unlike surface conditioners.
What products are best for high and low porosity hair?
High porosity hair benefits from richer, reparative formulations, including conditioners with glycerin, ceramides, emollients and oils to help reinforce and seal the cuticle, says Dr Khan.
On the other hand, low porosity hair tends to respond better to lightweight, water-based products with humectants. Gentle heat during conditioning can help products penetrate without overloading the hair.
But regardless of your particular porosity, the expert stresses that your scalp products should remain light to avoid inflammation or build-up.
Best products for low porosity hair
This ultra-gentle clarifying formula is perfect for low porosity hair as it eliminates build-up and grime in the form of a light, airy lather. A cocktail of actives refreshes roots and scalp, while delivering a gentle dose of hydration.
This lightweight conditioner is formulated at a pH of 3.5 to quench the thirst of dehydrated hair and create a light, protective layer on each shaft of hair. Milk thistle oil, which is packed with essential fatty acids and natural polymer rhizobian gum, holds moisture, locking it in to the shaft, but only where needed.
