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Water is the healthiest choice of beverage … right?

TikTok was not lovin’ it after a user posted a video showing a drop of McDonald’s water under a microscope, revealing small “microfibers” and “debris.”

The user, @closeintel — who posted the footage on July 1 — often examines different drinks under the microscope to see what’s really in them. This time, they took on an ice-cold cup of McDonald’s water after several requests from followers.

The 43-second clip — which has more than 3 million views on TikTok — initially shows there to be some frost from the cold temperature of the water before finding “microfiber[s],” which the user noted were to “be expected” from the plastic cup, lid and straw.

However, the water also contained some “debris,” which the user theorized could be from the ice.

“Your water may be totally different than mine. But I’ve heard it best to just order without ice,” they responded to a comment about how safe it is to drink the water.

Some McDonald’s users took to the comments section to shed light on why the H2O could contain some debris and microfibers.

“I used to work in McDonald’s and they never cleaned the ice cubes area,” one user revealed.

“You’re lucky you didn’t get the water from my old McDonald’s bc they NEVER cleaned their ice machine,” another wrote.

It’s not the first time the fast-food chain was called out for being unappetizing. One woman was shocked after she discovered a McDonald’s cheeseburger she kept for five years remained exactly the same. Another person found that a 10-year-old burger looked the same as when they bought it, too.

Meanwhile, a McDonald’s worker recently dished on the scary reason why you should “never” order fries at the iconic fast food chain.