I agree with Tek, but to maximise gains you gotta do all the basics: diet, training and sleep. I’ve had good gains using Androsol on the GVT2000 programme and getting 1-1.5g of protein - over a 4 week period I put on 7 pounds whilst maintaining 10% bf.
I've got one question though. You say you wanted to gain weight "drug free" but then you mention Androsol. Although it's legal (in most places) 4-AD is still a chemical that promotes testosterone production, so in that respect you may like to call it a "drug".