The Port & Company tall long-sleeve essential t-shirt is primarily made of cotton, which has a tendency to shrink when exposed to heat, especially during the first few washes. To minimize shrinkage, it's advisable to follow the care instructions provided on the Port & Company PC61LST label. Generally, washing the shirt in cold water and air-drying or using a low-heat setting in the dryer can help preserve its size and shape. However, some degree of shrinkage may still occur over time, so it's essential to consider this when selecting your size to ensure a comfortable fit after washing and drying.