How do guys like CT Fletcher get super thick dense biceps? They do super wide grip barbell curls to add density and thickness to their inner biceps!
Place your feet shoulder-width apart and hold the bar with an underhand grip, place your hands as wide apart as possible.
Your hands should be as close to the end of the bar as possible, within reason, to add stress to the inner biceps. Now let the bar hang down at arm’s length in front of you.
Curl the bar up in a wide range of motion and bring it up as high as you can, have your elbows close to the body and keep them fixed during the whole movement. For a variation, you can curl the bar up to your forehead as you would with forehead curls.