Close Grip vs Wide Grip Bicep Curls: Which Builds Bigger Arms?

You keep curling, but your arms aren't growing. You're putting in the work, but the results just aren't coming. The problem might not be your effort. It might be your grip.

How you hold the bar changes everything. It decides which part of your bicep grows. It shapes your whole arm. This is your clear guide to close-grip versus wide-grip bicep curls.

I will walk you through the simple science, show you exactly how to do each one, and give you a plan that works. Let's get this right.

Bicep Anatomy Made Simple: The Muscle Behind the Curl

First, know that your bicep is not one muscle. It is a team. You have the long head, which forms the outer peak. You have the outer peak, which is the long head. You have the short head, which builds the inner thickness. Now beneath the two is the brachialis. It raises your bicep and widens the appearance of your arm.

Every curl uses this team. But your grip chooses the star player. Research shows that different grips activate different muscles. One builds the mountain's tall peak. The other builds its wide base. You need both.

But let's be specific. What do we actually mean by close and wide?

First things first: what do we actually mean by "close" and "wide"?

Close Grip means your hands are placed at or inside the width of your shoulders. Your thumbs might even touch each other if you're using a straight bar.

Wide Grip means your hands are clearly outside your shoulders. Your pinkies will be well past your shoulder joints.

Your own shoulders are the measuring tape here. What's wide for someone with narrow shoulders might be normal for someone broader. Always go by your own body.

Now, why does this small detail matter so much?

Your bicep is more than just a little muscle. Its structure consists of 2 major parts, or heads. The long head runs on the outside, giving you that high peak when you flex. The short head sits on the inside, adding thickness and width. Underneath them both is the brachialis, a muscle that, when developed, pushes everything up and makes your whole arm look thicker.

Adjusting your grip changes the emphasis on these muscles. Science backs this up. Research using electromyography has shown that different grip types activate the biceps' heads in distinct ways.

Imagine it this way: you are not making a bicep; you are carving it. This grip lays the foundation; this grip adds the details.

Close-Grip Bicep Curls: For Thickness and Width

When you bring your hands close together, you do two important things. First, you put serious stress on the brachialis, that underlying muscle. This is the single best way to add real thickness to your arm, making it look wider from the front. Second, you target the short head of the bicep, building up the inner portion.

In short, if you want your T-shirt sleeves to feel tight, focus here. Many trainers consider this the best grip for bicep thickness.

How to do it right:

Hold an EZ-bar with a shoulder-width or narrower grip. Standing upright with the bar at arm's length, tuck it against your upper chest. Grip firmly, then lower the bar slowly by bending your elbows straight down toward your sides. Do not let them swing forward. Fight the temptation to use momentum, especially when fatigued, as slow, controlled reps are essential for muscle growth.

Wide Grip Bicep Curls: For the Peak

When you take a wide grip, you place maximum tension on the long head of the bicep. This is the muscle responsible for that rounded "peak" that pops when you flex. If you want that classic bicep shape, you need to train this part directly.

The wide grip also gives you a fantastic stretch at the bottom of the movement. Training a muscle under stretch is a powerful trigger for growth.

How to do it right

Use a straight bar or the outer handles of an EZ-bar. Place your hands just outside your shoulders. As you curl, try to keep your wrists straight and pull your elbows back slightly. Imagine you're trying to touch the bar to your collarbone to get that full squeeze. You won't lift as much weight here—that's normal. Focus on feeling the work in the outer part of your bicep.

So, which is better? Close grip or wide grip curls?

The truth is, neither is universally better. It depends entirely on your goal. Ask yourself: What does my arm need most right now?

Here's a quick comparison to help you decide:

• Want a taller, more defined peak? Prioritise Wide Grip Curls.
• Want a thicker, wider-looking arm from the front? Prioritise Close Grip Curls.

The smartest approach is to use both. They work together. One builds the base, the other shapes the peak. Research has shown that using a variety of grips leads to more complete muscle development than sticking to a single grip.

How to put this into your routine:

You can easily do both in one arm workout. The rule is simple: do the exercise that matters most to you first, when you're strongest.

• If your priority is the peak, start with Wide Grip Barbell Curls, then move to Close Grip EZ-Bar Curls.
• If your priority is thickness, start with Close Grip Curls, then move to Wide Grip.

A simple, effective bicep session could look like this:

1. Your Priority Grip Curl (Close or Wide): 3 sets of 8-10 reps
2. The Other Grip Curl: 3 sets of 8-10 reps
3. A finishing movement like Hammer Curls: 3 sets of 10-12 reps.

Final Thought

This week, walk into the gym with a plan. Look at your arms honestly. Do they need more peak or more thickness? Then, pick your grip and attack it first.

The difference won't happen overnight, but in a few weeks, you'll see a change. The muscle will respond when you train it with purpose.