I was taking it along with creatine, glutamine and hmb for four months last year. Between them they worked but I couldn't offer any guidance on breakdown amongst the four. I gained about 5 kilos bodyweight and 15-20 kilos on my bench. It could just have been that I also started taking whey protein then too. When I added in some tribulus I got a couple of spots on my normally spotless face. Jeez, acne at 47! The zma definitely helped me to sleep longer and deeper. When I stopped taking the zma I didn't feel any less and no longer use it.
Natural test boosters work for sure, I used hcgenerate and ostazol both work great to boost your cycle and pct. I use N2generate es (before hcgenerate es) as a bridge with my sarms between cycles.