You've been hammering the barbell curls for months, maybe years, and your peak is starting to look decent from the side, but then you catch yourself in the mirror from the front and... nothing. Your arms look skinny. It’s frustrating because you’re putting in the work, but that "thickness" just isn't there. If you want to know how to make my biceps wider, you have to stop thinking about the biceps as just one muscle. Most guys obsess over the biceps brachii—the "peak"—while completely neglecting the muscle that actually pushes the bicep out from the bone.
That muscle is the brachialis.
Think of it like this: the brachialis sits underneath the bicep. When it grows, it acts like a hydraulic jack, lifting the biceps brachii upward and outward. This creates that wide, 3D look that fills out a t-shirt sleeve. If you’re only doing palms-up curls, you’re essentially ignoring the very foundation of arm width. It’s a common mistake, but honestly, it’s one of the easiest things to fix once you understand the anatomy of the upper arm.
The Anatomy of Width: Why Your Curls Aren't Working
To understand how to make my biceps wider, we need to look at the three main players in the upper arm: the biceps brachii (short and long heads), the brachialis, and the brachioradialis.
Standard curls—the kind where your palms face the ceiling—primarily target the biceps brachii. The long head gives you the peak, while the short head adds some inner thickness. But here’s the kicker: neither of these muscles is responsible for the lateral width of the arm. That’s the job of the brachialis. It’s a deep muscle that originates on the lower half of the humerus and inserts into the coronoid process of the ulna. Because it doesn't cross the shoulder joint like the bicep does, its only job is to flex the elbow.
When you prioritize the brachialis, you’re literally building a shim that forces the rest of your arm to look wider. It’s a game of leverage.
Neutral Grip is Your New Best Friend
If you want width, you need to fall in love with the hammer grip. When your palm is neutral (facing your body), the biceps brachii is mechanically disadvantaged. This forces the brachialis and the brachioradialis (the thick muscle on your forearm) to take over the load. You’ve probably noticed you can hammer curl more weight than you can supinated curl. That’s because the brachialis is a powerhouse.
Try this: grab a pair of dumbbells and do a set of 10 slow, controlled hammer curls. At the top of the movement, squeeze as hard as you can. You’ll feel a pressure deep inside your arm, underneath the bicep. That’s the growth zone.
👉 See also: Brown Eye Iris Patterns: Why Yours Look Different Than Everyone Else’s
Exercises That Actually Build Lateral Thickness
Most people think "bicep workout" and think of three variations of the same standing curl. That’s boring and, frankly, inefficient if width is the goal. To maximize your results, you need to manipulate your grip and the angle of your humerus relative to your torso.
The Cross-Body Hammer Curl is a personal favorite for this. Instead of curling the dumbbell straight up toward your shoulder, you curl it across your chest toward the opposite pec. This slight internal rotation puts an insane amount of tension on the brachialis. It feels weird at first. Stick with it. The pump is unlike anything else.
Another underrated gem? Reverse Grip EZ-Bar Curls. By using an overhand grip (palms facing down), you almost completely take the biceps brachii out of the equation. This is a brutal movement because your grip will likely fail before your arms do. But for building that "wedge" of muscle on the outside of the arm, nothing beats it. Keep your elbows pinned to your ribs. No swinging.
Why Tempo Matters More Than Weight
I see guys in the gym all the time ego-lifting 60-pound dumbbells for hammer curls, swinging their hips like they’re at a dance club. You’re wasting your time. The brachialis responds best to time under tension.
- The 3-1-3 Method: 3 seconds on the way up, a 1-second hard squeeze at the top, and 3 seconds on the way down.
- The Dead Stop: Start every rep from a complete dead hang to eliminate momentum.
Scientific literature, including studies often cited by hypertrophy experts like Dr. Brad Schoenfeld, suggests that mechanical tension is the primary driver of muscle growth. If you’re swinging the weight, you’re using momentum—not tension. Slow it down. Feel the muscle stretch.
Overcoming the "Flat Arm" Plateau
If you’ve been training for a while and your arm width has stalled, it might be time to look at your volume and frequency. Most people train arms once a week on a "bro split." That might work for some, but if a body part is lagging, it needs more attention.
Research into protein synthesis shows that for natural lifters, the "anabolic window" for a specific muscle usually lasts about 24 to 48 hours after training. If you only hit your arms on Mondays, they’re sitting idle for five or six days a week.
✨ Don't miss: Pictures of Spider Bite Blisters: What You’re Actually Seeing
Try hitting your brachialis and forearms twice or even three times a week. You don’t need to do 20 sets. Just add two sets of heavy cross-body hammer curls at the end of your back workout, or a few sets of reverse curls on your leg day. This increased frequency keeps the signal for growth "turned on."
The Role of Forearm Development
You can’t have wide biceps with skinny forearms. It looks ridiculous. The brachioradialis connects the upper arm to the forearm, and when it’s developed, it creates a seamless flow of muscle that makes the entire limb look massive.
Heavy carries—like Farmer's Walks—are incredible for this. Grab the heaviest dumbbells you can hold and walk until your grip gives out. Not only does this build forearm thickness, but the isometric hold also taxes the brachialis.
Nutrition and the "Width" Illusion
Let’s be real for a second: if you’re at 20% body fat, your arm definition is going to be non-existent. You might have mass, but you won't have the "pop" that makes arms look wide and 3D. Conversely, if you're too skinny, no amount of hammer curls will help if you aren't eating enough to actually build tissue.
To build muscle, you need a slight caloric surplus. We’re talking 200–300 calories above maintenance. If you’re wondering how to make my biceps wider, the answer involves eating enough protein to support repair. Aim for roughly 0.8 to 1 gram of protein per pound of body weight.
Also, don't sleep on hydration. Muscles are roughly 75% water. When you're dehydrated, your muscles look flat and "stringy." If you want that full, wide look in the gym, drink a liter of water with some electrolytes about 30 minutes before you train. The difference in the pump is night and day.
Common Myths About Arm Width
"You can't change your genetics."
🔗 Read more: How to Perform Anal Intercourse: The Real Logistics Most People Skip
I hate this one. While it’s true that you can't change where your muscle inserts (some people have long bicep heritages, some have short ones), you absolutely can change the thickness of the muscle fibers you do have. You aren't stuck with "thin" arms. You just haven't targeted the right muscles yet.
"Close grip curls make biceps wider."
Actually, a wider grip on the barbell tends to target the inner (short) head of the bicep more, while a narrower grip targets the outer (long) head. Neither of these specifically targets the brachialis, which is the true key to width. If you want width, grip width on a barbell matters less than the orientation of your hand (neutral vs. supinated).
A Sample "Width-Focused" Arm Routine
Don't just add one exercise and hope for the best. Structure your arm day—or your "pull" day—to prioritize the muscles that provide lateral thickness.
- Weighted Pull-Ups (Neutral Grip): 3 sets of 6-8 reps. This is the ultimate mass builder for the brachialis.
- Incline Dumbbell Hammer Curls: 3 sets of 10-12 reps. Sitting on an incline stretches the long head of the bicep while the hammer grip hammers the brachialis.
- Cable Rope Curls: 3 sets of 15 reps. At the top of the movement, pull the rope apart. This "splitting" motion adds an extra layer of tension to the outer arm.
- Reverse Grip Barbell Curls: 2 sets to failure. Use a light weight and focus on the burn in your forearms and the side of your arms.
Notice there are no standard barbell curls here. That’s intentional. If your goal is specifically width, you need to deviate from the standard "bicep peak" routine for a few weeks to let the brachialis catch up.
Actionable Steps for Growth
Stop chasing the "peak" for a month. If you want to see a real difference in how your arms look from the front, you need to shift your focus entirely. Growth doesn't happen by doing what you've always done.
- Swap your primary curl: For the next four weeks, replace every set of standard curls with a hammer or reverse grip variation.
- Increase your frequency: Add 4 sets of hammer curls to your routine every other day.
- Focus on the eccentric: Spend a full 3–4 seconds lowering the weight on every single rep to maximize mechanical tension.
- Track your measurements: Use a soft tape measure to track the circumference of your arm, but also take photos from the front. The tape might not move much at first, but the visual "wideness" will change.
Consistency is the boring answer no one wants to hear, but it's the only one that works. The brachialis is a stubborn muscle, but once it starts to grow, it changes the entire silhouette of your physique. Put in the time, focus on the neutral grip, and stop swinging the weights. Your sleeves will thank you.