Jawzrsize works by simulating chewing resistance, training the masseter muscle and adjacent facial groups. Users bite down repetitively on a soft yet dense silicone mold for a few minutes per session, ideally multiple times per week. The intermediate model offers moderate resistance, suitable for those with some experience or strength.

The tool is portable and hands-free, making it convenient to use during activities like commuting or showering. Its simplicity is a strength, with no electronics or setup beyond an initial boil-to-fit process. That said, some buyers report issues with durability, noting cracks after a few months, and inconsistencies in bite alignment or comfort. The lack of accessories, such as a carrying case or lanyard, has also drawn criticism, especially given its price point.

Importantly, individuals with TMJ or strong gag reflexes may experience discomfort, making this device unsuitable for all users. While it can support toning, it does not reduce facial fat - diet and lifestyle remain key factors there. 

As a supplemental tool, it shows potential, particularly for strengthening jaw muscles and reducing minor sagging with regular use.