Chems can also be stacked, with no limit. Additionally, all chems can be crafted at a crafting station, so if you have the right materials there is no need to waste your money and purchase them. If you use a chem too often it may lead to addiction, so be careful. For example, some chems give you a greater damage threshold in combat, while others may increase intelligence for a short duration. In Fallout 4, chems have a variety of uses.
