As I mentioned in the post “How to Get Bigger Arms“, the biceps muscle is responsible for about 25% of the muscle mass in your arms.
The rest is made up of your brachialis and triceps. With the triceps making up over 52% of the muscle mass in your arms.
While the biceps is obviously less responsible for arm size.
The fitness gospel dictates:
“Thou shall not build big arms by ignoring the biceps, brah”.
All jokes aside, the biceps is also responsible for giving your arms a wider appearance. From the side, but especially from the front.
So training triceps will lead to bigger looking arms, training your biceps makes your arms look thicker and fuller.
Something interesting about the biceps is that exercising the muscle is not as straightforward as most believe.
When I ask you:
“How do you train your biceps?”
Probably most of you will answer, curls.
While that’s not necessarily wrong, what if I were to tell you that you’re missing out on a lot of muscle growth by doing that?
Yeah, you heard me right.
The biceps is not only about doing curls.
Which is why in today’s article, I wanted to go over how to effectively target and train the biceps through proper technique.
And ultimately help you build bigger and stronger arms.
Let’s get into it
How To Build Bigger Biceps
As per usual, in order to learn how to build bigger biceps we need to examine the anatomy of the muscle first.
Biceps Anatomy

The biceps, as the name suggests, is comprised of two muscles – the long head and the short head.
Both of which originate from the scapula and connect to the forearm.
Right underneath the biceps we have the brachialis:
Here is where things get interesting.
Contrary to popular belief, the brachialis is a much stronger elbow flexor than the biceps (resource).
What this means is that during curling exercises, the brachialis is doing more of the heavy lifting than your biceps.
This is because the brachialis does not cross the shoulder joint. Meaning that it can focus it’s full attention at the elbow.
The biceps is only partially active during this movement. And this is mostly because biceps does cross the elbow joint.
The biceps are triarticular – meaning that they act on three joints to perform three main functions (resource).
One of which is elbow flexion, as we already discussed.
Forearm supination, turning your palm up.
In fact, the biceps is the prime mover of forearm supination (resource).
Here’s a fun exercise for you. Go in front of a mirror and while keeping your arms to your side raise your forearm up to about 90 degrees with your palm facing each other.
Now twist your pinkie finger up as your palms start facing up and keep going until your palms are at an angle.
What you will immediately notice is that your biceps flexes.
And because the biceps crosses the shoulder joint, it acts on shoulder flexion – lifting your arm up in front raise.
In particular the long head of the biceps, that forms the biceps peak, assists the front delt with shoulder flexion.
So what does this mean? That you should stop doing curls and instead start doing front raises and forearm supinations to train the biceps?
No. Of course not.
What all of this should show you is that curling alone is not enough to target the biceps.
Supination and shoulder flexion target the biceps, they are not prime movers. And they lack potential for progressive overload.
While curling is both a prime mover and has a lot of potential for progressive overload.
Integrating those two movements to elbow flexion will increase biceps muscle activation and ultimately lead to bigger biceps.
And bigger thicker arms.
Optimal Biceps Training
As I already mentioned, the biceps is the primer forearm supinator.
Making supination really important for targeting the biceps. Because that more powerful underlying brachialis muscle can’t contribute to supination.
Adding supination to your curls means that the biceps will be responsible for lifting the weight. And thus taking away most of the brachialis involvement in the movement.
Let’s take a look at the barbell curls first and I’ll go over the dumbbell curls later in the article.
Barbell Curls
Unlike with the bench press, you want to take a more loose grip with your hands and fingers. This will reduce the activation of the elbow flexors of the forearm and increase biceps activation as a result.
So, wrap your thumb finger around the bar:
At the same time try to pull your shoulder blades back. Because the short head of the biceps attaches to the front end of the shoulders. Posteriorly tilting will pull tension to the biceps.
If you don’t know how to do that, here’s how. Shrug your shoulders up, pull them back, and then lower them.
As you begin a curl, think about applying the majority of the pressure on your pinkie and ring finger. Rather than your pointer and middle fingers.
This will force the wrist in a more supinated position.
You want to think about curling the bar out in front of you in an arc rather than straight up. This will generate more torque at the elbow and as a result more tension on the biceps.
And this will also cause shoulder flexion further increasing the activation of the biceps muscle.
That being said, this is no excuse for you to swing the weight. Your biceps should always be the prime mover.
So try your best and avoid using momentum to help you lift the weight up.
With the biceps you really want to focus on mind-muscle connection – squeezing the biceps and feeling it as you curl.
This 8 week training study by Schoenfeld et al. (study) found that focusing on squeezing the biceps resulted in significantly more muscle growth than just focusing on moving the weight. Almost doubling muscle size during the process.
Focus on squeezing the biceps to move the weight and you can take a short squeeze hold at the top of the curl.
Don’t hold that position for too long though as there is minimal tension there and you’re only unnecessarily exhausting yourself.
On the eccentric side. You want to lower the weight out in an arc again.
Remember that eccentric is just as, or more, important than the concentric for muscle growth. So don’t treat the negative as a time to relax and let the weight fall.
Control the weight as you lower it and actively resist the weight on your way down.
Dumbbell Curls
The main advantage of dumbbells is that they allow for your wrists to have a more neutral position and supinate throughout the concentric lift.
This will increase the involvement of the biceps as it’s more actively supinating the forearm.
To maximize on this you want to curl with your pinky finger in the center of the dumbbell. This will force your biceps to work harder to force supination.
Everything else is quite the same as with the barbell.
Other Biceps Exercises
So far, we’ve only looked at the standing barbell and dumbbell curls. What about preacher curls? Or spider curls? Or any other type of biceps exercise?
While you might not always be able to apply shoulder flexion, as some exercises restrict from doing that such as incline curls or behind the body cable curls. Which are intended to isolate the long head of the biceps.
You should always aim to supinate your wrist.
What about reverse grip curls?
Reverse grip curls have a pronated grip.
As a result it’s more effective at targeting the brachialis muscle, not the biceps.
Some sources show that a pronate grip has less than 40% muscle activation relative to a supinated grip.
E-Z Bar
While the barbell allows for a more supinated position of the wrist compared to an E-Z Bar, this difference is not really relevant.
The important thing is that you cue for supination as I discussed with the straight bar.
If the E-Z Bar is more comfortable on your wrist, then go with that.
Conclusion
The biceps might seem as a very straightforward muscle to train. You just curl.
But as we can see there are a lot of nuances to the muscle’s optimal training.
Can you build bigger biceps without doing any of this? Of course. You’re just limiting yourself by not increasing the activation of the biceps muscle.
And why would you want to do that?
Now you know how to build bigger biceps. All that’s left from you is to put in the work.