You can't begin to maximize the size of your biceps peak and arm circumference without also addressing the underlying and often-overlooked brachialis.

Like the biceps, the brachialis is an elbow flexor. Due to its position under the biceps, it literally pushes the biceps up as it gets bigger, making the biceps appear taller. Likewise, a well-developed brachialis increases the overall circumference of the upper arm.

 
If that's not enough, the brachialis is also visible on the side (lateral aspect) of the arm, as when doing a rear double biceps pose. You've gotta be pretty lean to be able to see the brachialis, but even if you've got some chub over it, your arm will still look thicker if your brachialis is properly developed.

In short, you really need to have a thick brachialis if you want bodybuilder-looking guns. But how do you go about accomplishing that?

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Developing Mass

If you want to get bigger muscles, you should lift big weights. The recipe is simple like that.

The best exercises to develop the biceps mass is heavy barbell curls and cheat curls. Let’s say you can do curls with 80 pounds, your aim should be to increase the weight up to 100 pounds. The harder your muscles work, the bigger they are going to be. Plus, we must not forget about the strength and forearm development.

If you want to increase the outer sickness, you need to do the biceps curls inward toward the center of your body. You can achieve it by using close-grip instead of normal grip. You can do concentration curls as well, but you need to bring the weight to your chest.

In case you want to improve the inner thickness as well as the mass, you can do the following exercises beside standing barbell curls. Hammer curls, seated, standing or incline dumbbell biceps curls, learn more about the best dumbbell exercises for biceps here.

Another important technique is to visualize yourself having huge arms as it is recommended by Arnold Schwarzenegger.

For Better Definition and Separation

In case you want to make your biceps more beautiful, there are several techniques you can utilize.

Firstly, you need to do supersets or even trisets and use as many exercises as possible, especially dumbbell ones. Dumbbell moves allow you to train your biceps from a various angle and support maximum isolation.

If you want to build higher muscles, you need to perform pumping workouts, mainly with dumbbells or cable. It is crucial to focus on the muscles as much as you can and flex the muscles at the top of the motion. Concentration curls with dumbbells or cable are especially good for making them high.

And what if you want longer biceps? To achieve it, you need to do exercises that support the fullest extension of the muscles. So the key is stretching. Do curls and focus on the lower third of the range of motion. Preacher biceps with free weights or on a machine is especially beneficial to target the lower part of the biceps, but you should lock your shoulders and elbows.

1. Hammers Curls

Hammer curls allows you to build the brachialis and brachioradialis in a way no other curl variation can. They derive their name from the hammer grip you hold on the dumbbell while performing them. This name also suitably hints at their ability to hammer your muscles for optimal gain. The hammer grip shifts the stress away from the biceps brachii and onto the brachialis and to a lesser extent, the brachioradialis.

Incline bicep curl

How to:
Sit on an incline bench and hold a dumbbell in each hand at arms length. Use your biceps to curl the dumbbell until it reaches your shoulder, then lower them back down to your side and repeat.

Why:
Beware: this position isolates the biceps and prevents other muscles from sharing the load. You can work the entire muscle by turning your wrists out slightly and keeping your elbows pointed towards the floor throughout the rep, a range of motion not available in other arm exercises.

Barbell Preacher Curl

What’s the one exercise that’s slightly better than a Scott curl using the flat side of a preacher bench? Using the preacher bench as it was intended, with your upper arms placed on the angle as you sit in the seat.

Strengths: While it’s a paper-thin margin between Scott and preacher curls, the difference comes at the very start of each rep, when your arms are extended. During a Scott curl, you tend to lose some muscle tension at that point, versus the muscular engagement maintained in a traditional preacher curl.

How-To: Set up a preacher bench so the top of the pad fits securely under your armpits. Take a shoulder-width, underhand grip on a straight bar or EZ-bar and position your arms parallel to each other on the pad. Keep your feet flat on the floor and your head straight as you flex your biceps to bring the bar as high as possible. Don’t allow your elbows to flare out or come off the bench. Flex strongly at the top before slowly returning the bar along the same path, stopping just short of full elbow extension before starting the next rep. You can also do this exercise one arm at a time with a dumbbell.