Your hairbrush, often overlooked in a personal hygiene routine, can become a repository for sebum, dead skin cells, styling product residue, sweat, dust, and microorganisms, potentially affecting hair and scalp health. Mark Blake, a trichologist and brand ambassador for KILLABRUSH, noted that a hairbrush acts as a "hoover for your scalp."
One primary concern is the reapplication of old oil and product onto freshly washed hair. Scalp sebum, along with residue from dry shampoo, hairspray, oils, and serums, can build up on bristles. When this dirty brush is used, these substances can be redistributed, leading to hair appearing greasy shortly after washing.
This build-up can also cause hair to look lank and less fresh, particularly for those with fine hair. Blake explained that repeatedly applying old product residue back into the hair and onto the scalp is not conducive to healthy-looking hair. The weight of accumulated oil and product can make hair feel heavier and less vibrant.
Beyond cosmetic concerns, unwashed hairbrushes can harbor bacteria, yeasts, and fungi. While not every dirty brush is a health hazard, studies have detected microorganisms, including species of Trichophyton, which are associated with fungal skin and scalp infections. Bathrooms, being warm and moist environments, can encourage the proliferation of these microorganisms on brushes stored there.
Repeated contact with a dirty brush can also contribute to scalp irritation. Similar to how dirty makeup brushes are avoided for facial skin, an uncleaned hairbrush repeatedly applied to the scalp can transfer yeast, bacteria, and residue. This can lead to sensitivity, irritation, and inflammation in some individuals. Sweat from exercise can exacerbate this by adding more oil and microorganisms, including Malassezia globosa, a yeast linked to dandruff.
Dirty bristles can also cause increased pulling and tension on the hair. When oils, dead skin, and product residue coat the bristles, they may not glide through hair as intended, leading to snagging. This is particularly relevant when brushing wet hair, which is more vulnerable to breakage due to its stretched state.
Experts recommend a simple cleaning regimen: remove trapped hair after each use and thoroughly clean the brush approximately once a week. Blake suggests washing brushes with warm water and a small amount of shampoo, potentially one containing salicylic acid to help dissolve oils and product residue. He also emphasized the importance of not sharing hairbrushes to maintain hygiene.
As scalp care becomes more sophisticated, Blake noted that the hairbrush has been an overlooked aspect of hair hygiene, despite its frequent contact with the hair and scalp.