A barber on TikTok has claimed people's hairlines might naturally change over time because the skull shifts back as we move from young adulthood to middle age.
Of course, in men, this could just be happening because you're going bald, but there does appear to be some scientific merit to the idea that bone structure changes as we get older.
The original claim was made on TikTok by user @jessesbarbershop, who - while holding a model skull - said: "If you look right here [the front of the skull] you'll see this big bone right in the front.
"But, if you notice, that's exactly where your hairline sits, so as you age this bone is changing shape and growing.
"Oftentimes what people will find is that their hairline is getting pushed back, and they're not losing hair, they're not thinning in the hairline at all, but the hairline is just getting pushed back."
He concluded: "It's probably because your skull is literally changing shape."
Now, Jesse - for all of his undoubted expertise as a barber - provides no scientific evidence for why this is, or if it's even a thing, which many in the comments have pointed out.
That being said, there does appear to be some scientific evidence that could back up this cranial contention.
Let's have a look at that, shall we?
A study was performed by scientists and plastic surgeons from the University of Rochester over in the USA.
They assessed CT scans of patients of all different ages to examine the underlying bones of the face to better understand the aging process.
Dr Howard Langstein and Dr Robert Shaw checked out the skulls of around 60 adults and found that the older people get, the more their face changes.
Their findings were later published in the journal Plastic and Reconstructive Surgery.
Langstein later told NPR: "We saw changes around the eye, and then in the cheek area and in the jaw.
"And if you think about it, it kind of makes sense. When people age, the eyes appear hollow, deep-set. And, in fact, that's what we found.
"The cheek bones right beneath the eye socket descend somewhat and come back in. As a result, they don't give as much support to the lower eyelid."
The same is going on in the jaw. Langstein continued: "If you think about the aged face, there's sort of a lack of definition in the jaw line. And that's what we saw in the CT scans.
"It's one of those things that, in retrospect, you sort of say, 'Duh, I should have known that!'
"Nothing stays the same on the body. Everything ages."
While that doesn't completely prove the theory espoused in the original video, it certainly does suggest it might have some truth to it.
So, if you're staring at your hairline each day and wondering if you're going bald, perhaps there is a chance that you're actually not losing your hair, but changing your skull shape.
Then again, maybe you're just going bald, and you should try to come to terms with that.