If you want to know the single most important thing regarding how to build big arms, it’s this: it’s going to take time. To add a few inches — months at least. To add several inches more after this — years at least.
If it were that easy to build big arms, everybody would be walking around with 20 inch arms. You may be disappointed to hear this, but remember — this only serves to work in the favour of the more determined trainee. Most people will not stick at it so they don’t get the goods. If you do, you will.
Exercise wise you’ll have to use variety just like in all areas of bodybuilding. But, the most effective methods I have found is to build big arms is doing curls with a straight heavy barbell. But, again like I have said this will not work constantly; you need to change things regularly (around every four weeks).
When working out the sheer size high repetitions of 10 – 12 and sets of around 3 – 5 usually work well.
Also, as I have said another article if you decide to use dumbbells to build your biceps I advise you to lift using a supreme grip (hand pointing upwards). This keeps more biceps muscle fibres under constant tension rather than many of the fibres becoming slack like when you turn your hand inward and downwards.
The second most important thing to remember is that you need to build the triceps up as they will contribute most of the size to your upper arm — two thirds more than the biceps do. Exercises such as close grip bench pressing is a great way to build the triceps. As for isolation exercises for the triceps you should try various triceps extensions using barbells or dumbbells.