If you do curls and still feel like your arms look narrow from the front or kind of flat from the side, brachialis exercises are probably the missing piece. Your biceps matter, of course, but the brachialis is one of the main muscles that gives your upper arm that thicker, fuller look, and training it well can change both how your arms look and how strong your pulling feels.
Why Your Arms Can Look Strong but Still Not Look Full
A lot of arm training is built around the mirror muscle: the biceps peak. So you do standard curls, feel a burn, maybe even get a decent pump, but your arms still do not look as wide or dense as you want.
Here’s the thing: bigger-looking arms are not just about the biceps brachii. If you want your upper arms to look fuller in a T-shirt, especially from the front and outer side, you need to pay attention to the muscle underneath and beside the biceps too. That is where the brachialis comes in, and it is why relying only on palms-up curls is a mistake.
What the Brachialis Actually Is
The brachialis is a deep upper-arm muscle that sits underneath the biceps brachii and helps bend your elbow. In plain English, it is one of your main curling muscles.
That matters for two reasons. First, it adds actual thickness to your upper arm, because it sits under the biceps and can push that area outward as it grows. Second, it helps with elbow flexion, which means it contributes to the strength you use in curls, rows, chin-ups, pull-ups, and plenty of everyday pulling movements. Research even describes the brachialis as a major contributor to elbow flexion torque, which is a technical way of saying it does a lot of the work.
Where the Brachialis Sits on Your Arm
Picture your upper arm like layers. The biceps is the muscle you see most easily. The brachialis sits underneath it, closer to the humerus, your upper-arm bone. It connects the upper arm to the forearm and helps pull the forearm upward when you bend the elbow.
Because of that position, growing the brachialis can make your biceps look like they sit a little higher and your arm look wider overall. It is not some illusion trick. It is simple anatomy. More muscle in that area makes the whole upper arm look more substantial.
What the Brachialis Does During Curls and Pulling
The brachialis performs elbow flexion, which just means bending your elbow. Every time you curl a dumbbell, pull yourself up to a bar, or row a handle toward your torso, that muscle is involved.
It does not work alone. Your elbow flexors include the biceps brachii, the brachialis, and the brachioradialis. So even on back day, your brachialis is getting some work. That is why stronger arms and stronger pulling often rise together. The catch is that if all your direct arm work is biceps-dominant, the brachialis can stay undertrained even if it is technically active.
Why Brachialis Training Helps Arms Look Thicker
If your goal is bigger-looking arms, brachialis work pays off fast. Not because it is a secret hack, but because it targets a part of the upper arm that many people barely train on purpose.
Your biceps peak gets attention, but arm thickness is what makes an arm look impressive relaxed, hanging by your side, or seen straight on. The brachialis helps create that thickness. So if your arm routine is just barbell curls, incline curls, and concentration curls with your palms turned up every time, you are leaving size on the table.
Brachialis vs. Biceps vs. Brachioradialis
The biceps brachii is the flashy one. It helps flex the elbow, but it also helps supinate the forearm, meaning turning your palm upward. That is why classic curls with a supinated grip light it up so well.
The brachialis is deeper and less visible on its own, but it adds depth and width to the upper arm. It is less about the “peak” look and more about dense, full arms.
The brachioradialis sits more on the forearm side and helps give that strong bridge between upper arm and forearm. When it is developed, your arms look more athletic and complete rather than just biceps-heavy.
Why Grip Position Changes What You Feel
Grip position changes which muscles get the best mechanical advantage. Palms-up, or supinated, curls usually favor the biceps more. Neutral-grip curls, like hammer curls, and pronated curls, with palms facing down, tend to reduce biceps dominance and shift more work toward the brachialis and other elbow flexors.
That is not just gym folklore. A 2023 handgrip study found that grip changes meaningfully affect elbow-flexor activation, which is exactly why arm training should not stop at one curl style.
The Best Brachialis Exercises to Build Fuller Arms
No single exercise is magic. But a mix of neutral-grip and pronated-grip curls usually works best if you want fuller arms.
Hammer Curl
This is the go-to brachialis exercise for most people, and for good reason. With a neutral grip, your palms face each other instead of facing up. That takes some emphasis away from the biceps and makes the brachialis work harder.
Form matters. Keep your elbows near your sides, curl without swinging, and lower the dumbbells under control. If you feel your shoulders taking over, the weight is too heavy. Hammer curls also tend to feel friendlier on the elbows, which makes them easier to train hard and consistently.
Cross-Body Hammer Curl
This is a hammer curl done across your torso, bringing the dumbbell toward the opposite shoulder. For a lot of people, it feels more natural on the wrists and elbows than strict straight-up hammer curls.
Use this when standard hammer curls feel awkward or when you want a slightly different line of pull without overcomplicating your workout. It is a simple swap, not a whole new category of exercise.
Reverse Curl
Reverse curls use a pronated grip, palms facing down. That grip shifts emphasis away from the biceps and makes the exercise a strong option for the brachialis and brachioradialis.
The common mistake is turning it into a forearm fling. Keep your wrists stacked, your elbows close, and your torso still. If the rep starts looking like you are trying to throw the bar upward with momentum, back off the load.
Preacher Hammer Curl or Preacher Reverse Curl
The preacher setup helps because it limits cheating. Your upper arm is supported, so you cannot rock your body to get the weight moving. That makes it much easier to tell whether your elbow flexors are actually working or your shoulders are sneaking in to help.
This is especially useful if you always “feel curls” everywhere except your arms.
Rope Hammer Curl
A rope attachment on a cable stack gives you smooth tension through the whole rep. That feels good, honestly, especially at the top where dumbbells sometimes lose a bit of challenge.
That said, a cable is not automatically better. Trendy curl variations are fun, but they are not guaranteed to beat basics. In one 2025 EMG study, a traditional dumbbell curl actually produced higher biceps activation than a Bayesian cable curl. Different goal, yes, but the lesson is useful: novelty is not the same thing as effectiveness.
Zottman Curl
The Zottman curl is a practical combo move. Curl the weight up in a stronger position, then rotate into a pronated grip and lower it that way. Up easier, down harder.
That gives you a nice blend of biceps, brachialis, and forearm work. It is not the best pure loading move for any one muscle, but it is a very smart all-around option when you want more from one exercise.
Reverse EZ-Bar Curl
If straight-bar reverse curls bother your wrists, the EZ-bar often fixes that. The angled grip feels more forgiving for a lot of people, especially if your wrists get cranky with pronated work.
This is also a good option if you want to load reverse curls a bit heavier in a stable, gym-friendly setup.
How to Do Brachialis Exercises Without Letting Your Biceps Take Over
A brachialis exercise only works as intended if you actually do it like one.
Use the Right Grip Instead of Just More Weight
The trick is not grabbing heavier dumbbells right away. Often, changing your grip does more than adding ten sloppy pounds.
Neutral and pronated grips change the exercise stimulus in a useful way. So before chasing load, make sure the movement choice matches the muscle you want to emphasize.
Keep Your Elbows Quiet
Your elbows should not drift all over the place, and your shoulders should not launch the weight upward. Once a curl turns into a mini body-rock, tension leaves the target muscles fast.
A little natural movement is fine. But if your whole upper body starts doing backup dancer duty by rep eight, the weight owns you.
Control the Lowering Phase
The lowering phase, called the eccentric, matters a lot for growth. Do not just drop the weight after the hard part is over.
Take two or three seconds to lower it with control. Your arms should stay loaded the whole time. That simple fix makes light-to-moderate weights work much better.
Train Through a Full Range of Motion
A full range of motion in curls means extending your elbow enough at the bottom to actually lengthen the working muscles, then curling all the way up without turning the top into a shrug.
Half reps have their place at the end of a hard set. But if every set is a half rep from the start, your arm development gets short-changed.
Common Mistakes That Hold Back Brachialis Growth
Most people do not need more arm exercises. They need fewer mistakes.
Only Doing Supinated Curls
Standard dumbbell curls and barbell curls are fine. Good, even. But if every direct curl you do uses a palms-up grip, your biceps get the spotlight and the brachialis gets leftovers.
If thicker-looking arms are the goal, add neutral and pronated work on purpose.
Using Momentum on Every Rep
Swinging, leaning back, and rolling the shoulders forward all make the exercise easier for the wrong reasons. If your curl turns into a standing backbend by the last few reps, the weight is too heavy.
Use momentum sparingly, maybe on the very last rep of a set. Not on every rep from the start.
Going Too Heavy on Reverse Curls
Reverse curls usually require less weight than regular curls. That is normal. Forcing the same load you use on a supinated curl often irritates wrists and elbows and wrecks your form.
Swallow your pride here. The smaller plate that actually hits the target beats the bigger one that turns into a mess.
Ignoring Pulling Exercises
Rows, chin-ups, pull-ups, and neutral-grip pull-downs all train the elbow flexors. That matters because your brachialis is already involved in more than arm day.
So do not think of brachialis work as separate from your upper-body plan. Think of it as direct support for better pulling and fuller arms.
How to Add Brachialis Exercises to Your Routine
Programming this is simpler than it sounds.
If You Train Arms on Their Own
Put brachialis-focused work after your first main curl or pair it with triceps work. For example, you could do a classic curl first, then hammer curls or reverse curls second, when your biceps are already a bit fatigued.
That sequencing often makes it easier to actually feel the brachialis working.
If You Pair Biceps With Back
This is one of the easiest setups. After rows, pull-downs, or chin-ups, your elbow flexors are already warm, your joints feel ready, and you do not need a huge amount of direct arm volume.
A few focused sets of hammer curls or preacher reverse curls at the end of back day work very well.
Simple Sets, Reps, and Weekly Volume
For most people, 2 to 4 elbow-flexor exercises per week is enough, with 2 to 4 sets per exercise. Moderate rep ranges work best, usually around 8 to 15 reps.
You do not need to annihilate your arms. You need enough quality volume to progress. For frequency, twice per week is a very good default, especially if you also train back hard.
A Sample Brachialis-Focused Arm Workout
A simple session could look like this: hammer curls for 3 sets of 8 to 12, reverse EZ-bar curls for 3 sets of 10 to 12, preacher hammer curls for 2 or 3 sets of 10 to 15, then one classic supinated curl for 2 or 3 sets of 8 to 12.
That is more than enough. You could knock that out at the end of a Tuesday back session in about 20 minutes and get real results if you stay consistent.
What Research Says About “Best” Brachialis Exercises
The research is useful here, but it does not hand you one perfect answer.
Why Neutral and Pronated Grips Matter
The practical takeaway is clear: supinated grips tend to increase biceps brachii emphasis, while neutral and pronated grips reduce biceps dominance. That makes those grip styles useful when you want more balanced elbow-flexor development instead of just chasing biceps activation.
Verywell Health also notes that the brachialis is especially important when the forearm is pronated, which lines up well with how reverse curls tend to feel in real training.
Why There Is No Perfect Isolation Exercise
You cannot completely isolate the brachialis. It works with the biceps brachii and brachioradialis, and that is just how elbow flexion works.
The good news is that it does not need perfect isolation to grow. Research suggests the brachialis has a distinct EMG pattern, which means it is not just a silent passenger under the biceps. But in training, smarter exercise selection matters more than chasing some mythical secret move.
Why Basic Exercises Still Work
Basic exercises still work because consistency beats novelty. A dumbbell hammer curl, reverse curl, or preacher variation done well for months will usually outperform random flashy cable experiments done for two weeks.
That is especially worth remembering if your social feed keeps serving “the one curl nobody knows.” Most of the time, grip choice, clean reps, and steady progression are the real difference-makers.
Questions You May Have Before You Start
A few common questions tend to come up right before you actually add this stuff to your program.
Can You Really Isolate the Brachialis?
Not completely. But you can emphasize it by choosing neutral and pronated curl variations, keeping your form clean, and not relying only on supinated curls.
How Often Should You Train the Brachialis?
Twice per week works well for most people. If your back training already includes lots of rows, pull-ups, and pull-downs, you may only need a few direct sets on top of that.
Are Hammer Curls Enough?
Hammer curls are a great foundation, but they are not the whole story. Adding reverse curls or preacher-style variations usually gives you better overall arm development and helps cover more angles.
Do You Need Cables or Special Equipment?
No. Dumbbells and an EZ-bar are enough for most people. Cables and bands are useful options, but they are not requirements.
What Should You Try First?
Swap one standard curl slot for hammer curls and one for reverse curls for the next few weeks. Then pay attention. Notice how your arms feel during pulling work, how your elbows tolerate the training, and how your upper arms look relaxed at your sides. That is where brachialis work starts to show up.
