wikipedia -- Andarine (S4)
End of the article said that clinical trials were abandoned because a metabolite of S4 was toxic. Doesn't sound too good, but S4 was never an anabolic. It was meant as a blocker for DHT binding to the prostate.
After a
brief scan of the study cited in the relevant section of the relevant Wikipedia entry the takeaways from the cited work appear to be as follows:
Humans express an enzyme involved in the metabolism of S4 in a polymorphic manner; this is not true for several common species of lab animals. Thus the normal animal models utilized to determine initial human dosage parameters do not apply to S4.
A form of the polymorphic enzyme present in humans in concentrations that differ, perhaps by a lot, from person to person produces a metabolite of S4 which is itself a substrate of S4 giving rise to the possibility that S4 could reform in the body after it has been first metabolized. We might reasonably infer that this could cause the activity of S4 to vary wildly from person-to-person. Or not.
But the killer for S4 in terms of its theraputic value, if true, again from the cited study: S4 appears to be tissue selective in some species but not in humans.
Thus, if the cited paper is correct (and I've not misread it or glossed over something in the few minutes I spent on it), S4 is a non-tissue selective compound whose effective human dosage can't be estimated via the traditional methods and whose activity is likely to vary in a wide & unpredictible manner in humans. At this point it becomes rather self-evident why interest in its further development might be on the wane.
But I didn't see anything about "nasty toxic sides" so I'll ask again: if you have any evidence, preferably from a source that can't be edited by anyone on the 'net without review or verification, that S4 is actually harmful to humans please share it. I'm sure I'm not the only one who would appreciate a pointer to such information if it indeed does exist.
