I have been reading alot about these sarms and how they are apparently less suppressive than AAS. When I researches LGD 4033 and I found it does suppress natural testosterone even at low doses. This study used only small doses of 0.1mg 0.3mg and 1mg per day. It reduced total test for all groups but more importantly even though it reduced shbg free test was also reduced. Click on the charts at the bottom to see the hormonal effects.
It's hard to see how something that can suppress on such low doses can be claimed to be mild or doses of 10mg per day could give a net gain in muscle with such a reduction in free testosterone. That said sarms seem to have a more individual effect judging by the mixed results I have seen. Another concern would be the problems associated with low test and it's metabolites (estrogen, dht etc) resulting from suppression.
I could see with its reduction in shbg lgd 4033 could be useful stacked with a test cycle.