I don't recall pulling up a study on it,just explaining the absorbtion processes,which are literally identical in spite of which route of administration is used.The injectible is 17aa,the oral is 17aa.They both are broken down via hepatic metabolization,and each will pass through the liver multiple times before being ultimately excreted.I don't necesssarily have a problem with injecting it,I just don't think it's necessary.But there are those who swear by winny's ability to increase growth at the site of administration,so maybe therein lies an argument for why one would want to...