Caffeine is one of the most used substance all over the world. Ideally it should be consumed as less as possible. Find out Half Caff vs Green Eye caffeine content in the following sections. However Half Caff Caffeine levels and Green Eye Caffeine levels may differ with their brands, quantity of additives used, types of additives used etc. Below we have given you a generalized idea of safe levels of caffeine in Half Caff vs Green Eye, their side effects and benefits.