The process consists of passing 'threads' through the skin to accentuate the outer edge of the lips, mainly the Cupid's bow, making lips appear more defined. Think of it like lip liner with an extra boost. But is lip threading safe? Does it hurt? And is it really worth it?

These threads are composed of poly-L-lactic acid, or PLLA, a biocompatible synthetic substance. "They are placed into the lip to stimulate collagen production and therefore change both the shape and size of the lip," says Dr. Tijion Esho, cosmetics doctor and owner of the ESHO Clinic. But...

"The collagen stimulation is modest, so there is a more noticed change in definition than volume of the lip itself," Esho says. In other words, the outline of your lips is likely to be more raised and therefore defined. Think of it like semi-permanent lip liner with an extra lift.

Like all cosmetic procedures, there is a chance lip threading could be uncomfortable. A dental anesthetic can be injected, but using it might not allow for a true assessment of the lip in different expressions, for example smiling or laughing, or even your resting neutral face.

But that means it would potentially be more painful than a filler. Plus, if multiple punctures are needed, downtime from bruising or swelling could be up to two weeks. Is it safe?

All medical procedures will carry risk, but within the correct, experienced medical professional's hands, lip threading can be a safe procedure. Plus, the threads break down over time in your lip, so you don’t need to get them removed. The catch...

This isn’t necessarily a safety risk, but lip threading isn’t instantly reversible the same way filler are. If you aren’t happy with the thread, you just have to wait for it to dissolve. Worst-case scenario...