Bizarre simulation showing how lip filler works has people saying it's 'painful to watch'

Lip filler is a hugely popular procedure these days, but a simulation on exactly how it works has left viewers feeling uneasy.

Most people know someone who has lip fillers - if you don't, it might just be that the provider did a particularly good job at being subtle.

Some people love them, some people hate them, some probably couldn't care less about them. But many of these people have been united over a simulation of the procedure which goes into detail about how it's done.

Lip fillers are a hugely popular procedure (Getty Stock Image)

Created by YouTuber Zack D Films, the video shows how a needle is used to deliver the filler into the tissue in the lips.

It shows the needle sinking into both the upper and lower lips, squeezing synthetic hyaluronic acid into the tissue and demonstrating how the lips increase in size as a result.

The simulation is only short, but the entire procedure can actually take up to two hours, according to the Cleveland Clinic, due to various steps involved.

Healthcare providers begin by applying anesthetic to numb the area, which can take about 15 to 30 minutes.

The person administering the filler then uses the needle to inject the liquid, causing what the clinic describes as a 'pinching sensation' which may make your eyes water.

The procedure can take up to two hours (Getty Stock Image)

About 1 milliliter of filler is used in the procedure, and the needle is inserted approximately 2.5 millimeters. All the while, the healthcare provider may apply ice to help minimize swelling and bruising.

Millions of people will be very familiar with this process, but that hasn't stopped viewers from feeling uneasy after watching the simulation on YouTube.

"Imagine how painful that would be," one viewer commented, as another added: "I can't be the only one who got jumpscared by that needle in the FIRST second. Have mercy Zack, lol."

The simulation also made its way to Twitter, where one viewer wrote: "Painful to watch."

If you're not good with needles, look away now!

There are a number of reasons why people might get lip fillers, including to restore a previous lip size as you age, making your lips more symmetrical, or smoothing out wrinkles.

In the US, people hoping to have the procedure must be at least 21 years old, and must meet with a healthcare provider beforehand to discuss the process.

Once the filler has been injected, it can typically last 12 to 18 months before the filler begins to wear away.