For a slim fit t-shirt, size L will probably suit you. Alternatively, you can also choose size XL with a 20% chance. As for shrinkage, the product is made of 100% cotton. When the correct washing instructions are followed for cotton products, the risk of shrinkage is minimized. It is recommended that you wash at 30 degrees, do not use bleach, and do not dry in the dryer. It is also recommended to reverse the ironing process and do it at low heat. You can check the product label for detailed care instructions. We wish you pleasant shopping.