store supplements

I was wandering what are 2 good supplements that I could buy at like walmart or gnc that could help with my gains or flaacid hang. Just some simple supplements, nothing complex. I am 23 years old and taking zyrtec allergy medicine. Will zinc help with my gains, because they are non existent after almost 2 months of homemade pumping, and 3 years of half ass pe on and off.