You can’t get 20-inch arms naturally unless you plan on joining a sumo team in the near future. During the Golden Era of Bodybuilding, legit 20-inch arms in a lean state were a rarity of the first order.
There is evidence suggesting that Arnold Schwarzenegger’s arms were smaller than the official 22 inches. Arthur Jones, the man who popularized HIT (High-Intensity Training) and the use of the Nautilus machines, reported that Arnold’s arms were “only” 19 7/8 inches. When you keep that in mind, it becomes painfully obvious that obtaining a set of 20-inch arms without anabolic steroids and other performance-enhancing drugs (PED) is a pipe dream.
Virtually every modern IFBB bodybuilder uses more drugs than the former champions and yet even today 20-inch arms are relatively rare.
Truth be told, most natural bodybuilders will have a really hard time getting their arms to 15-16 inches in a lean condition.
Having ripped 15-inch arms is not bad at all. In fact, if you have that, you are doing better than 90% of the population. Once again – be grateful for what you have. Try to elevate your spirit and don’t kill yourself and others over trivial things such as arm measurements:
“People are strange: They are constantly angered by trivial things, but on a major matter like totally wasting their lives, they hardly seem to notice.”
― Charles Bukowski