All testosterone is the same, modifications of extracts from tropical yams or soy.
Testosterone is modified by adding ester groups to it. It is then not testosterone and will not interact with testosterone receptors, aka androgen receptors [AR]. The esters of T are soluble in oil, when that is done, you have injectable "testosterone". You inject typically 100mg of testosterone ester in oil per week. In the body, the oil and T esters are slowly absorbed, which is a time release delivery. T esters when absorbed into the blood stream as free molecules are subjected to a few different processes that remove the ester groups from the T esters. This result, drum roll please, bio-identical testosterone. The 100mg of T ester yield roughly 70 mg which is 10mg/day, roughly the T production of a young virile male. Thus T injections are a time release delivery of bio-identical T.
The bio-identical advocates will not be very happy if you point that out. They are trying to make you go to them because the doctors who do injections are injecting "synthetic" hormones. Actually the definition of synthetic means man made and their bio-identical hormones are man made. There are anabolic steroids which are molecular modifications of testosterone that are used by body builders that are absolutely unnatural synthetic molecular structures. These are not use for testosterone replacement therapy [TRT] because they are not testosterone.
So there is your anti voodoo explanation.
Bio-identical is but one option for TRT. If is an alternative to injecting T. Injecting T is the gold standard in terms of delivery and "absorption". It is very inexpensive. The bio-identicals are basically transdermal where about 10% gets absorbed, at best, and 90% or more gets wasted. So that option does have relatively high costs, in some extremely high costs.
If you go to a clinic that delivers the 'drugs' to you, that can be very costly. If you get a script and get that filled your self, you are better off.
You will find that many doctors have more than your interests at heart.
Many "clinics" will not take your insurance and you have to pay out-of-pocket. You best bet is to get TRT from a regular doc who writes scripts for you and the doc uses your insurance. But finding a doc, endo or uro who is not an idiot is very difficult. That is the barrier to effecting and affordable hormone care for men. Uro's and Endo's are the worst of the lot. They are ill-informed and dole out cookie cutter ignorance.