For instance:
1) The body has a negative feedback loop with androgen receptor activity, so trying to find a chemical that binds strongly to the androreceptors while not shutting the system down seems illogical.
I think the SARMs are the latest attempt to circumvent this conundrum. One of the problems is that the BBing community will use these things at 5 to 50 times the therapeutic dose and the marketers will still claim that they are not suppressive. For instance, Ostarine is used at 1-3 mg/d in clinical trials for cachexia merck.com/licensing/news-and-events/gtx-press-release.html. They are minimally suppressive at therapeutic dose but have very little in the way of BBing level anabolic effect at that clinical dose. Clinical indications for these things are sarcopenia due to aging, osteoporosis and cancer cachexia.
2) None of these chems have been approved for any sort of mass market use, so understanding long term effects is truly uncertain.
Ostarine and Ligandrol are in advanced rials at least phase 2 at the moment. Buy phase 3 there will be several years of data to reflect upon. At licensing these drugs will be subject to adverse events reporting as are all US licensed drugs. Other Western countries are the same.
3) the point is to grow as much as possible without ruining the body. SARMs don't belong to this class of goals exclusively.
Some users will have what they feel are more realistic goals. Some people will be interest in more mild effects that accent an already excellent training and diet regimen. Also, women may find some SARMs more appropriate for their goals than more androgenic compounds.
4) AAS is well-known, well-studied, well-documented and is easy to get and will more likely be real and properly dosed, something we can't say about SARMs yet.
AAS probably have a more dramatic side effect profile that the two most studies SARMs, Ostarine and Ligandrol, at least antidotally at this point.
5) with a little research and a little cash, one can run test-only with profoundly better results, enjoy the process more & be certain about and have less short and long term negative health effects than SARMs. At the very least, one could be comfortable with the known trade-offs of a Test-only cycle.
Many men on TRT must use an estrogen blocker and other ancillaries even at 200 mg/w. Also many older TRT patients require periodic phlebotomy to control red cell values. A typical 500 mg/w BBing type test cycle will almost without exception result in high estrogen and DHT levels. From there it depends on individual sensitivities as far as side effects but over time such levels can lead to polycythemia, prostate hyperplasia, water retention, high blood pressure, etc.
SARMs are the latest attempt to produce a product that can address some of the same clinical indications as AAS without the same level of the above side effects. Whether they are successful or not, we will have to wait and see. My prediction is that some will be licensed in Western nations with the US not being among the first. There is money to be made and there have been vert few adverse events in clinical trials thus far. Whether or not they are useful for BBing purposes, I would say yes but the amounts needed would be 5-25 times as much as therapeutic dose much like that seen with AAS.