A video showing just how dirty your hairbrush might be has gone viral on TikTok, garnering more than 3 million views.
The clip, created by @everything_tidy, shows how much grime washed off her brushes after she left them to soak.
According to the TikTokker, she was inspired to wash her brushes after another creator (later identified @unitfour) made a video explaining that dirty hair can be caused by using a dirty hairbrush.
In a bid to test the theory, she filled a basin with hot water and shampoo, and left the brushes soaking for a while - and was disgusted by what she discovered on her return.
A TikTok creator wanted to see if her innocuous looking hairbrushes could be harbouring some serious grime - so she put them in a basin full of hot water and shampoo for an hour
Narrating the clip, she says: 'I watched a video last week and it was a lady and she said, "Maybe the main reason why your hair is getting greasy or oily quickly isn't, in fact, because of your hair follicles, and it is in fact because of your brush".
'So I'm going to put that to the test. I've put all my brushes in the sink and we're going to leave them for a bit.
'I've used hot water and shampoo because she didn't state what she used.'
Upon returning to the basin, she says: 'So I've left them for an hour and come back to check the water.
After a good soak, the TikTokker was disgusted to see that the water had turned brown - which she described as 'disgusting'
'Oh my god, that's disgusting. Ladies, don't forget to wash your hairbrushes. I didn't even know that was a thing, but look at the state of that.'
The video received mixed responses, with some users pledging to wash their own implements immediately. One wrote: 'Goes and washes hairbrushes now.'
Another seemed disappointed to have another chore to add to their list, saying: 'Do we have to wash everything?'
Some revealed they don't even use hairbrushes, with a commentator saying: 'I'm glad I don't use a brush and just use my hands.'
However, a number of users were shocked that not everyone already knows to wash their brush.
'The fact that some of y'all don't know to wash your hair brushes regularly is appalling,' one wrote. 'Wash your hair = wash your brush at the same time.'
Expert reveals the shocking things that might happen if you don't wash your hairbrush every week
'The build-up on your hairbrush can serve as nidus for bacteria and yeast overgrowth, so there is an infection risk,' dermatologist surgeon and RealSelf contributor Sejal Shah, M.D told Good Housekeeping.
And, as she reveals, despite spending time and money developing a hair care routine, that could all be undone in one go as soon as you grab hold of that dirty brush.
She says that the build-up of residue on your comb is going straight back onto your hair and is even making it greasier just moments after you've washed it.
Good Housekeeping recommend that you remove the dead clumps of hair every week and then tend to each of your brushes depending on their type.
With plastic brushes and combs, they advise using a bowl of warm water mixed with a gentle or clarifying shampoo, before rinsing and letting them air dry.
While wooden brushes may seem straightforward to clean, the finish on the wood could get damaged with harsh chemicals.
A 'quick swish' with a light soap is recommended to keep your brush fresh and clean, or if, you're unsure, consult the manufacturer's care leaflet.