Undefined Jawline

The mandible, the jawbone, is the frame the entire lower face hangs on. With age it loses height, and its angle below the ear becomes less sharp, a slow remodelling rather than a sudden change. As the frame shortens and rounds, the tissue above it has less edge to define, and the line from ear to chin loses its crispness.

The deep fat that once gave the cheeks their lift gradually loses its support and settles lower in the face. Much of it comes to rest along the jaw, adding fullness that rounds off a border that used to be sharp. The jawline blurs not because the jaw gained anything of its own, but because volume from above settled on the line.

Collagen, the protein that gives skin its firmness, declines from the mid-twenties at about 1% per year, and elastin, the fibre that lets skin recoil, is barely renewed after puberty. The skin along the jaw and upper neck slowly loses its tension, like an elastic that has lost its snap. A border that depends on taut skin softens as a result.

The area along the jaw and beneath the chin stores fat readily, and it often holds onto it even after weight comes back down. Repeated cycles of gain and loss also stretch the skin in this zone, so each swing can leave the transition between face and neck slightly less distinct than before.

Not every jawline concern is about aging. Some people, often men seeking more definition, though by no means only men, have a jaw that is naturally narrow, soft or short, set by how the bone developed. Mild asymmetry is also normal: one side of the jaw is rarely a mirror of the other, and small differences usually need no correction at all.