Isolation of highly purified untagged proteins is crucial in today’s R&D programs. Up to now, recombinant protein production approaches were often based on the use of “tags” to make protein purification (and solubility) more convenient. Unfortunately, these tags can be real experimental hurdles in downstream applications. Protein experts are now considering “tag-free” alternatives (including outsourcing) for producing untagged proteins more rapidly, more efficiently, and without jeopardizing the rest of the research project. Let’s see how this is possible.