@ogsteve you still can get something like this one (there is only 1 in stock now though and a huge shipping cost), it's lyophilized, or other variants when they are in stock. It says intermuscular, but if you split the dose into 2 or 3 you can do it subcutaneously too, in my opinion. But we know more or less what is there and may just compose a synthesized surrogate as well, which is more accessible.
I would use a mix of
Thymulin, Vilon, Crystagen - 0.5-1 mg each, and Thymogen 0.02-0.05 mg. Also supplement Zinc.
See here.
Or you can use pills of Vladonix or Thymusol, better sublingually, on empty stomach.
But, so far, I didn't see any distinctive results in blood markers on any of these compounds, except a transient increase of neutrophils.