Sleep is probably most people's favourite time of the day. Waking up the next morning, not so much. Sometimes made worse by the fact that the corners of your eyes are coated in yellow gunk as your alarm goes off.
Ever wondered what this crust, which we sometimes call 'sleep in our eyes' actually is?
Wonder no more:
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The natural occurrence is quite gross to talk about, but it's something we can all relate to.
You may flick it away once you wake up or maybe it gets removed when you wash your face, but we get rid of it one way or another.
A TikTok has revealed exactly what that yellow gloop is and why it happens specifically while we sleep.
Andrew Huberman explains: "If you have ever woken up in the morning and you have some crust on your eyes.
"And you know that crust, that kind of yellowy stuff, sometimes it's yellow, I know this is kind of gross.
"That's actually dead bacteria that your eyes have successfully defeated during your night's sleep.
"So when you wipe those away, you're taking the casualties of a war that you won during your night's sleep and you're whisking those away."
More or less then, when you wake up in the morning and flick away the crust in your eyes, you are disposing of the deceased intruders that dared to breach your body's well-being.
Going into more detail, Medical News Today and the Cleveland Clinic say the crust in your eyes is actually a combination of dead skin cells, dirt, dust, oil and mucus. Lovely.
When we're awake we blink away all this nastiness, but with out peepers shut during sleep, it all builds up, congeals, and dries out - ready for us to deal with in the morning.
It's grim, but important for keeping our eyes clean and healthy.
People were absolutely mind-blown when they found out the reason behind the crust, leaving several comments on the TikTok.
One said: "I refuse to lose even when I’m sleeping."
Another user rightly commented: "Starting the day with a victory."
A third user said: "When I was in kindergar[t]en i put them in my tea," followed by a skull emoji.
An even more disgusting revelation there from that user, but I guess we were all kids once.
That should be a driving force for everyone then, as your body keeps fighting for you while you're sleeping, you can rest to be well-prepared for the next day.
Joshua Nair