Those mysterious white marks that appear on your nails have finally been explained.

Have you ever looked down at your fingernails and wondered what the HELL those little white marks that sometimes appear on them are?

(You may also wonder, ‘Are my nails long enough to be pierced?’, but then again, that could just be me…)

There’s no need to consult Dr Google with those frantic 1am searches that may or may not say “GOOGLE, MY NAILS HAVE WHITE SPOTS AM I DYING?”

Because, we have the answer.

And no - it's not because you're deficient in calcium, which is often offered up as the explanation.

According to The Mirror, for the most part, those pesky white marks are nothing to worry about.

Those marks - scientific name punctate leukonychia - usually appear due so some trauma that has occurred to the nail.

Listen: Should we let our young daughters get manicures?

Like, closing a door on your nails. Or flicking a pen between your fingers. Or simply having a nibble on your nails when your nervous.

It can even happen when you're tapping really impatiently on the desk when your boss just won't stop nagging you about that report.

The white marks usually form at the base of your nail bed and over time, grow out. By the time you notice them, you've usually forgotten what caused them in the first place. Hence, the stress about what they are.

Very rarely, the white marks can indicate something more serious, and could be signs of zinc deficiency, which is found in foods like beef and spinach.

Worse, the marks could signal malaria, Hodgkin's disease or sickle cell anaemia.

But of course, usually you will have a range of other symptoms to indicate these illnesses, and not just leukonychia.

If your entire nail turns white, it could mean something like heart disease or diabetes, and if your white mark stretches across the whole nail, it could mean that you've been poisoned.

But don't worry, "if you can see them...you can't have been, because if you had, you'd almost certainly already be dead", says The Mirror.

So, no need to worry at all, really.