[rabidvermin]

Generally, proteins you eat get broken down by the digestive system into their component amino acids. There are some notable exceptions where proteins can apparently get absorbed intact, but generally proteins are broken down upon injestion. Supplementing intra-venously might be the only option.

[bduerst]

And even then this protein may provide negative feedback for the production of other unidentified proteins, which are kept in check by the exercise activity, meaning that flooding your system intravenously could lead to some undesirable or harmful results.