Further data from randomized, double blind, placebo controlled (and ideally also active-controlled),
well-powered clinical trials would clearly be most useful.
Limitations of this Review the literature search focused on English language studies only.
As a result, important publications may have been omitted, given that substantial clinical investigation of both compounds has taken place outside the Unites States
the initial intent was to base this review only on studies meeting all the predefined study selection
criteria
However, given the pervasiveness of potentially flawed studies for both products, some studies of lesser quality (meeting some, but not all, selection criteria) were included out of necessity (particularly for SAM-e)