We should make it clear from the beginning that this is not a method of preserving fertility, but an attempt to preserve sperm production. This is an attempt, and not a method ensuring preservation of reproduction, while sperm freezing actually is such a method.
During hormone protection by medicinal therapy, the function of the testicle is suspended, so that the chemotherapy doesn't affect it. An unpleasant side effect is the lack of testosterone that you will experience – problems with your sexual function will occur.
This can be fixed by providing you with testosterone replacement therapy. Whether we apply this method depends on the specific case, and it is a supplementary approach, not an alternative to sperm freezing.
Different studies present controversial results regarding its effectiveness. In high-dose chemotherapy, it has no effect.