Hammer Curls: How to Do Them, Muscles Worked and Benefits

Hammer curls are a dumbbell arm exercise where you curl the weights with your palms facing each other, like you are swinging a hammer, instead of facing up as you would in a standard bicep curl. That small change in grip does a lot: it shares the load across your biceps, the brachialis muscle underneath, and the brachioradialis in your forearm, which makes hammer curls one of the most efficient ways to build thicker, stronger-looking arms. They are also easier on the wrists and elbows than normal curls, so they suit most people. Here is how to do them properly, what they actually work, and how to fit them into a routine.

How to do a dumbbell hammer curl

You only need a pair of dumbbells. A bench helps for some variations, but the standing version is the staple.

1. Set up. Stand tall with your feet about hip-width apart, a dumbbell in each hand, arms hanging by your sides. Turn your palms so they face your thighs (neutral grip) with your thumbs pointing forward.
2. Brace. Tighten your core, pull your shoulders back and down, and pin your upper arms against your ribs. This is the position your elbows should stay in for the whole set.
3. Curl up. Bending only at the elbow, lift both dumbbells towards your shoulders. Keep your palms facing each other the entire way; do not let your wrists rotate. Drive up smoothly, no swinging.
4. Squeeze at the top. When the dumbbells reach shoulder height, pause for a beat and squeeze. You should feel it in the front and side of your upper arm.
5. Lower under control. Take two to three seconds to lower the weights all the way back down until your arms are fully straight. That slow negative is where a lot of the growth happens.

Aim for full reps every time: all the way up, all the way down. Half-reps are the most common way people short-change themselves on this lift.

Muscles worked

Hammer curls are popular because they train three muscles in one movement:

• Biceps brachii. The headline arm muscle on the front of your upper arm. It still does plenty of work in a hammer curl, just not quite as much as in a palms-up curl.
• Brachialis. A flat muscle that sits underneath the biceps and is one of the strongest flexors of the elbow (anatomy reference). As it grows it pushes the biceps up, which makes the whole arm look bigger and wider. The neutral grip targets it harder than almost any standard curl.
• Brachioradialis. A forearm muscle running from the upper arm towards the wrist that flexes the elbow in any forearm position (anatomy reference). The hammer grip loads it directly, which is why your forearms feel the burn.

Your grip and the small stabiliser muscles around the shoulder and wrist also work to keep the dumbbells steady, so there is a knock-on benefit to grip strength too.

Benefits of hammer curls

Thicker arms, not just a bigger peak. Because the brachialis and brachioradialis get more attention, hammer curls build the width and density of the arm rather than only the front. Pair them with standard curls and you cover the whole picture.

Easier on the joints. The neutral wrist position is more comfortable than the palms-up position of a barbell or standard dumbbell curl. If your wrists or elbows niggle on normal curls, hammer curls are often the version you can keep doing pain-free.

Better grip and forearm strength. Holding the dumbbells in a hammer grip works your forearms and grip in a way supinated curls do not. That carries over to deadlifts, rows, pull-ups and carrying the shopping in one trip.

Simple and scalable. All you need is one pair of dumbbells. A set of adjustable dumbbells makes it easy to nudge the weight up as you get stronger without filling your spare room with a full rack.

Common mistakes

• Swinging the weight up. If you are heaving with your back and hips, the weight is too heavy. Stand still, let your arms do the work, and use a load you can control.
• Letting the elbows drift. The moment your elbows slide forward, the lift turns into a front raise and the brachialis stops doing its job. Keep them glued to your ribs.
• Rotating the wrists. The neutral grip is the whole point. If your palms turn up as you curl, you have wandered back into a standard curl.
• Cutting the range short. Stopping at the halfway mark, or not straightening the arms at the bottom, leaves gains on the table. Full reps, every time.
• Rushing the lowering phase. Dropping the weights quickly wastes the most productive part of the rep. Control the way down.

Variations

Once the standard version feels easy, switch things up to keep progressing.

• Alternating hammer curls. Curl one arm at a time. It lets you focus on each side and naturally cuts down on body swing.
• Seated hammer curls. Sitting on a weight bench removes leg drive, so you cannot cheat with momentum. Strict and humbling.
• Cross-body hammer curls. Curl the dumbbell across your body towards the opposite shoulder. This bias hits the brachialis and the outer biceps even harder.
• Incline hammer curls. Done lying back on an incline bench, this stretches the biceps at the bottom for a bigger range of motion.
• Band hammer curls. Loop a resistance band under your foot and curl with a neutral grip. Great for home or travel when you have no dumbbells to hand.
• Kettlebell hammer curls. A pair of kettlebells work fine too, though the offset weight makes them feel a little different at the top.

A simple way to program them

Hammer curls are an accessory lift, so slot them in after your bigger pulls (rows, pull-ups) or at the end of an arm session.

• 3 to 4 sets of 8 to 12 reps
• Once or twice a week
• Rest 60 to 90 seconds between sets

Whether you spread that across one session or two makes little difference for growth once the total weekly volume is matched (training frequency meta-analysis), so pick the schedule you will actually stick to. When you can hit the top of the rep range on every set with clean form, add a small amount of weight and start again. Progress on this lift is steady rather than dramatic, so log your numbers and chase small wins.

Recommended reads

1. The best adjustable dumbbells in the UK
2. The best kettlebells in the UK
3. The best weight bench in the UK
4. The best resistance bands in the UK
5. Home gym equipment guides