Loop density is the number of individual loops per square inch. More loops, more weight. More weight, more structure.
Terry construction stacks loops vertically from a base fabric. The base holds tension. The loops provide mass and air pockets.
Low-density terry collapses under its own weight after washing. The loops fold over. They mat down. The fabric loses half its thickness in six months.
High-density terry maintains loop architecture. Each loop supports the ones beside it. The structure stays rigid. Compression resistance increases with density until the base fabric can't support additional weight.
440GSM sits at the threshold. Any denser and the base starts to buckle. The fabric waves instead of lying flat. You feel it immediately when you lay the piece on a table.
Manufacturers avoid this zone. Too much material cost for marginal consumer differentiation. Too much risk of base failure during production. Most industrial terry tops out at 380GSM.
The Industrial Tier runs 440GSM because that's where loop integrity holds under repeated compression. You can fold it daily. The loops spring back. The hand stays consistent.
500GSM requires a different base construction entirely. The loops need more anchor points. The weave density doubles. This is Foundry Tier territory. The Lab is building the base architecture now.