The “lip flip” is the latest viral beauty trend, popping up all over social media to make you feel self-conscious about yet another part of your body.

Three years of staring at ourselves on video calls appear to have had a big effect: more than 14 million non-surgical procedures were undertaken in the U.S in 2020, up from less than 13 million in 2018.

Dermal filler and botulinum toxin, or Botox, are known as “injectables” and are becoming increasingly popular as the industry moves from the scalpel to the syringe.

Filler plumps soft tissue and can be used around the face, commonly in the lips, while Botox freezes the muscles and is used to smooth wrinkles on the face. In the lip flip, botulinum toxin is injected into the lip. The aim is not to shape the lip, but more to push it out and create the illusion of a fuller top lip.

Newsweek spoke to Jasmin Taher, a qualified dentist and aesthetic practitioner based in west London, about the treatment.

What Is a Lip Flip?

A lip flip is a non-surgical procedure that uses botulinum toxin injections to relax the lip muscle. The result is that when you smile, the top lip is less inverted and pokes out a bit more, so your gums and teeth show less.

People who have a gummy smile because of lip muscle hyperactivity have used this technique for many years.

This is not the same as a lip augmentation, according to Taher. “Lip augmentation is a procedure where filler is used to volumize and shape the lips, with instant results, lasting 6-12 months or even longer.

“A lip flip simply relaxes the lip muscle, which leads to less gum show on smiling. It does not volumize or shape the lip and results are not instant. It takes about two weeks for results to be visible and on average the results last around 2-3 months.”

How Did the Lip Flip Become Popular?

The hashtag #lipflip has more than 162 million views on TikTok, with another 15.2 million views for #lipflipchallenge. Interest in the technique has surged as beauty trends move from an overly “done” look to more natural results.

TikTok user @southerlybower underwent a lip flip procedure in September because she believed her smile was “gummy” and she wanted to tackle lines on her upper lip.

In her video, which has over 650,000 likes, she said: “I didn’t want to have these dramatic big lips that look that they have filler in. I just wanted a little something and actually the main focus was I started to get quite a deep line here and here [pointing to upper lip] and I just wanted to stop them from getting any worse really.”

In a follow-up video two weeks later, she said she could “see a huge, huge difference.” Her upper lip lines had completely disappeared, “so that’s awesome because I wasn’t expecting that. I’ve also actually got lip here and I never really had lip here so that’s from where it’s flipped it up slightly.”

She added that the main reason she wanted the treatment was to make her smile more even—and was delighted with the result. “Oh my God, the difference in the smile, so before when I would smile my whole lip would just go up and I’d be quite gummy.”

The TikToker said the comments from viewers who had also had the procedure were “Marmite“—or polarised. Some described negative reactions, such as finding it hard to eat and suffering from dribbling, but she had not experienced this herself.

The Difference Between an Augmentation and a Flip

The two procedures are “completely different,” said Taher.

A lip flip “has very little effect on the lips at rest. Some patients do report that their lips look subtly more everted with a slight pout at rest, however this is not the main goal of treatment. This procedure does not volumize the lips or change the shape, so for patients that want a change in how their lips look at rest, lip augmentation with filler is more suitable.

“Another limitation compared to filler is how long the results last. Given how much the lip muscle is used in articulation, expression and food intake, the results wear off relatively quickly. So, patients must be aware that maintenance is high.”

The effect of a lip flip lasts 2-3 months, rather than the 6-12 months or even longer with lip augmentation.

This is reflected in the treatment’s price. According to the American Board of Facial Cosmetic Surgery, “while a full syringe of lip filler costs between $500 and $1,000, the Botox lip flip typically requires only 4-6 units of Botox, which cost between $10 and $15 each.”

Recovery Time and Side Effects of Lip Flips

One of the main advantages of the lip flip is the minimal recovery time. Taher said the procedure usually takes about 1-2 minutes and 2-4 quick injections. “Small bumps and some redness are visible at the injection sites but this subsides after about 10-15 minutes.”

Taher warned that, as the lips relax, some patients “feel some temporary weakness in their upper lip. This is particularly noticeable when the lip muscle is contracted. For instance, whilst drinking through a straw.”

Some patients also report that extra effort is needed to say words beginning with a B or P. “This usually subsides within two weeks, and is not visible to others.”

Taher added: “To reduce the chances of these side effects, lower doses should be used with a follow-up after two weeks where an additional dose can be used, if required.”

If you are considering a lip flip but are undecided, she recommended a simple test. “Have a look in a mirror and smile as wide as you can. Then press on the skin above the lip. This will show you what the results will potentially look like. If when you do this, the lip flips out and less gum is visible, you are a good candidate. If there is excessive tooth coverage, you are not a good candidate.”