how to build 21 inches biceps

These are the basic workout for the beginners. They can be done at any place not necessarily at the gym. You can do it at home. All you need is a pair of dumbell or a dumbell (if you only have one). A barbell will be a bonus.

1. Standing Dumbell Curl

Stand on your feet, shoulder wide. For maximum concentration, only use one dumbell. One hand at one time. From starting position, lift the dumbell up slowly. exhale while lifting the weight.Bring the weight down slowly for maximum benefit from the negative motion. Inhale while bringing the weight down. You have just complete one rep.
For a beginner 3 sets of 12, 8, 8 reps.

2. Supinated dumbell curl

The same body position as dumbell curl. The only different is you supinate the dumbell from the start position. For those who dont have any idea how to supinate the dumbell, this is how you do it. From the start position, hold the dumbell with the palm facing inward. Bring the weight up slowly and turn the dumbell until your palm is facing your shoulder at the end of the motion. Exhale when lifting and inhale when bring the weight down.
3 sets of 12, 8, 8 reps

3. Hammer curl

Stand on your feet. Palm facing inward. Lift the weight all the way without turning the palm. Same breathing technique.
3 sets of 12, 8, 8 reps

Make sure the movement (up and down) done approximately 3 seconds up and 3 seconds down. Rest 1 minutes after every set.