I took that 6-oxo crap when i was less knowledged. It didn't do shit. There were no side effects for me... yea, more importantly there were no main effects. In the documents and studies conducted by Bailor university (i think), there was an increase in Free test by 226% but there were no significant changes to the subjects' body composition.
Some people told me that those studies were flawed because the "free test" was actually the product itself (6-oxo) which structurally looks and behaves very similar to testosterone. But it has a very weak ability to bind to androgen receptors and very weak anabolic properties of its own. a.k.a a very weak steroid and hence no changes in those ppl's body composition.
I'll just stick to heavy lifting, eating right, fish oil, creatine, whey protein and Zinc.