Fat pads protect our feet but we destroy them by walking and running on hard surfaces

This loss of fat pads is due primarily to damage from shearing forces from walking and running on smooth, unyielding man-made surfaces (concrete, asphalt, hard floors). The damage is compounded by poorly designed and poorly fitted socks and shoes. Thorlos protect the fat pads from shearing forces by transferring these forces from the fat pads to the cushion fabric of the Thorlos; and where fat pad degradation has already occurred, Thorlos engineered cushion fabric helps replace the function of the natural pads.

Protection is the "root cause" of comfort
Why Fabrics that work well on our bodies work poorly in our shoes
Cotton, wool and silk (all natural fabrics) absorb moisture ["Absorption" is defined as retention]. Wool claims to "wick," which is not true.

Inside the shoes, natural cushion sock fabrics become ineffective and even harmful to the feet 
They absorb moisture, become saturated and collapse. Result: no protection. Acrylic "wicks" moisture ["Wicking" is defined as transmission or movement of moisture by capillary action], moving it to the outer materials of the shoe where it is released into the outside environment. Acrylic cushion sock fabric maintains resiliency and provides a more natural yielding, forgiving, dynamic environment for the foot (like walking barefoot in grass or sand).

Result
More protection, more comfort.

Net Effect
Acrylic cushion fabric creates a more "NATURAL" environment inside a shoe or boot
The irony is that it requires a man-made (or natural blended with acrylic) cushion fabric to create a more natural surface inside a shoe; but remember that shoes and boots themselves are man-made surfaces. Therefore, the only effective protective measure is to help counteract the negative aspects of one "man-made" surface with another "man-made" surface. Thorlos exclusive acrylic cushion fabric is more "natural" inside a shoe.