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.
