The human body contains many natural polymers, such as proteins and nucleic acids. Cellulose, another natural polymer, is the main structural component of plants. Most natural polymers are condensation polymers, and in their formation from monomers water is a by-product.
Alopecia areata is one type of hair loss that typically causes patches of baldness. In some cases, total baldness develops. In many cases, the hair re-grows, typically after several months. In some cases, the hair loss is permanent.
Perhaps one of the most common hormone-related causes for hair loss is a thyroid problem. Both too much thyroid hormone (hyperthyroidism) and too little (hypothyroidism) can lead to hair loss. Treating the thyroid disorder can often reverse the hair loss.