Where did you get this info? How would injecting test subQ lower estrogen when it aromatizes into estrogen? I don't know the specifics, but injecting test subQ may cause less conversion to estrogen but it certainly doesn't lower it. Also subQ injections are only good for extremely low oil volumes, like at 0.3cc or less, so less than a TRT dose per injection
Sub q injections are fine you will see man almost identical effect. It however does not decrease estrogen. Depending on the carrier oil you can only get away with about .6ml per injection location. It's pretty hard to do sub q successfully.