Testosterone is the building block in, well, building muscle so the last thing you want to do is inhibit it or suppress testosterone in any kind of way. When you have low testosterone, building muscle is nigh impossible, never mind the potential of a higher quality of life.
Now I’d like to say “NO! Cannabis does not affect testosterone” BUT the jury is out. There are conflicting studies saying that it does lower testosterone while others say there is no decrease whatsoever. This study “suggests a minimum of 24 hours are required for testosterone to return to pre-smoking levels” but does not come to a concrete answer. Another study suggests that there is no correlation, but keep in mind for most of these studies cannabis is being smoked (combusted) which again, results in a plethora of health issues in itself.
Some studies show positive testosterone boosting qualities of zinc and magnesium. Zinc, magnesium and vitamin B6 is the basis of ZMA, a supplement that you can get at any grocery store that boosts your recovery.