The largest bicep (male) belongs to Mostafa Ismail (Egypt).
Even when he’s not flexing, Mostafa Ismail of Egypt probably has a bigger bicep than you’ve ever seen. His left arm is 24.5 inches around when relaxed and balloons to 25.5 inches when he makes a muscle — larger than the average human head. Ismail has spent the last 11 years of his life—he trains six days a week and eats six meals a day—trying to impress with his biceps and now hopes to compete in “naturally enhanced body-building competitions.” He would need to use both biceps there.