What muscle do hammer curls work on?

Hammer curls primarily work the brachialis and brachioradialis, the forearm muscles that sit underneath and alongside the biceps, along with the biceps themselves. The neutral, palms-facing grip shifts more emphasis onto these muscles than a standard curl, which is why hammer curls are a staple for building forearm size and thickness.

Is hammer curl better than bicep curl?

Neither is better outright, they train overlapping but different muscles. The standard bicep curl puts more direct tension on the biceps through a palms-up grip, while the hammer curl shifts emphasis onto the brachialis and forearms with a neutral grip. Most well-rounded arm programs include both rather than choosing one over the other.

How do I know if I'm doing hammer curls correctly?

You are doing hammer curls correctly if your elbows stay pinned close to your torso throughout, your wrists stay straight in a neutral, palms-facing grip, and you lower the weight under control instead of dropping it. If your torso swings or your elbows drift forward, the weight is too heavy for strict form.

Is a 50 lb hammer curl good?

Curling a 50 lb dumbbell per arm with strict form is an advanced level of strength that most recreational lifters take years of consistent training to reach, well above what most intermediate lifters use. For most people, a controlled 15 to 30 lb hammer curl with good form is a solid, realistic working weight.

Should beginners do hammer curls?

Yes, hammer curls are beginner friendly, since the neutral grip is easier on the wrists than a standard curl and the movement has a low skill floor. Beginners should start with light dumbbells and focus on keeping the elbows pinned to the torso before adding weight, since forearm and elbow tendons adapt more slowly than the biceps themselves.

What is a common mistake people make when doing hammer curls?

The most common hammer curl mistake is swinging the torso or heaving with the shoulders to move the weight instead of curling with the arms alone, usually a sign the load is too heavy. Letting the elbows drift forward mid-rep is a close second, since it shifts tension off the target muscles and turns the movement into a shoulder exercise.

Are hammer curls for shoulders?

No, hammer curls are primarily an arm exercise, targeting the brachialis, brachioradialis and biceps rather than the shoulders. The shoulders play a minor stabilizing role in keeping the upper arm still through the rep, but they are not the muscles the movement is built to train or grow.

Hammer Curl: Form & Muscles Worked

Hammer Curl

How to do the hammer curl with correct form: neutral grip, elbow position, and the swinging mistakes that reduce forearm and bicep engagement.

Quick answer: Keep a neutral thumbs-up grip and elbows close to your sides, curl without swinging, then lower the dumbbells slowly through a full comfortable range.

Dumbbells beginner Biceps, Forearms

How to Do It

Stand holding a dumbbell in each hand at your sides with palms facing your body (a neutral grip, thumbs forward).

Keep your elbows pinned close to your torso and your upper arms still.

Curl both dumbbells up toward your shoulders, keeping your wrists straight and the neutral grip throughout.

Squeeze briefly at the top without letting the elbows drift forward.

Lower under control back to the starting position, resisting the weight on the way down.

Common Mistakes

Swinging the torso or using the shoulders to heave the weight up instead of curling with the arms alone.

Letting the elbows drift forward or away from the body, which reduces bicep tension.

Rushing the lowering phase instead of controlling the full eccentric range.

Rotating the wrist mid-rep instead of keeping the neutral grip that defines the hammer curl.

The hammer curl’s neutral grip shifts more work onto the brachialis and forearms than a standard bicep curl, which is why it’s a staple for building forearm size and thickness alongside the biceps.

It’s also easier on the wrists and elbows for lifters who feel discomfort with a supinated (palms-up) curl grip, since the neutral position keeps the forearm in a more natural line.

Pair it with a rowing movement like the barbell bent-over row on a pull day, or run it alongside a standard curl in a dedicated arm day workout for complete bicep and forearm coverage.

Hammer Curl vs Bicep Curl

Both curls train the elbow flexors, but the grip changes which muscle does the most work. The standard dumbbell bicep curl uses a palms-up grip that puts the biceps brachii through its longest range of tension. The hammer curl’s neutral, palms-facing grip shifts emphasis onto the brachialis and brachioradialis, the muscles underneath and alongside the biceps that give the arm its overall thickness.

	Hammer Curl	Bicep Curl
Grip	Neutral (palms facing in)	Supinated (palms facing up)
Primary emphasis	Brachialis, brachioradialis, forearms	Biceps brachii
Wrist and elbow comfort	Often more comfortable	Can bother sensitive wrists
Best for	Forearm and arm thickness	Peak bicep size

Neither replaces the other. Most well-rounded arm programs include both curls in the same session or rotate them week to week for complete coverage.

Muscles Worked by the Hammer Curl

Primary: brachialis, brachioradialis
Secondary: biceps brachii
Stabilizers: forearm flexors and the shoulder, which keeps the upper arm still through the rep[1][2]

The brachialis sits underneath the biceps and, when well developed, pushes the biceps up and out, which is why hammer curls are a common addition for lifters chasing overall arm size rather than biceps peak alone.

Hammer Curl Alternatives

Dumbbell bicep curl: the supinated-grip counterpart, putting more direct tension on the biceps brachii.
Reverse curl: an overhand, palms-down grip that shifts even more emphasis onto the brachioradialis and forearms than the hammer curl.
Cross-body hammer curl: curls the dumbbell across the body toward the opposite shoulder, adding a slight rotational demand.
Barbell bent-over row: not an isolation substitute, but a compound pull that trains the biceps and forearms indirectly alongside the back.

References

National Strength and Conditioning Association. Anaerobic and Muscle Endurance Development: Lifting Guidelines. National Strength and Conditioning Association (2017)Back to claim
Brad S Currier, Alysha C D'Souza, Maria A Fiatarone Singh, Caroline V Lowisz, Eric S Rawson, Brad J Schoenfeld, Abbie E Smith-Ryan, Jeremy P Steen, Gwendolyn A Thomas, N Travis Triplett, Tyrone A Washington, Timothy J Werner, Stuart M Phillips. American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews. Medicine & Science in Sports & Exercise (2026)Back to claim
Deborah Riebe, Barry A Franklin, Paul D Thompson, Carol E Garber, George P Whitfield, Melissa Magal, Linda S Pescatello. Updating ACSM's Recommendations for Exercise Preparticipation Health Screening. Medicine & Science in Sports & Exercise (2015)

See our exercise methodology for how this evidence is applied and its limits.

Frequently Asked Questions

What muscle do hammer curls work on?: Hammer curls primarily work the brachialis and brachioradialis, the forearm muscles that sit underneath and alongside the biceps, along with the biceps themselves. The neutral, palms-facing grip shifts more emphasis onto these muscles than a standard curl, which is why hammer curls are a staple for building forearm size and thickness.
Is hammer curl really effective?: Yes, the hammer curl is effective for building forearm and brachialis size, muscles a standard bicep curl trains less directly. It is also easier on the wrists and elbows for lifters who feel discomfort with a palms-up curl grip, since the neutral position keeps the forearm in a more natural line throughout the movement.
Is hammer curl better than bicep curl?: Neither is better outright, they train overlapping but different muscles. The standard bicep curl puts more direct tension on the biceps through a palms-up grip, while the hammer curl shifts emphasis onto the brachialis and forearms with a neutral grip. Most well-rounded arm programs include both rather than choosing one over the other.
How do I know if I'm doing hammer curls correctly?: You are doing hammer curls correctly if your elbows stay pinned close to your torso throughout, your wrists stay straight in a neutral, palms-facing grip, and you lower the weight under control instead of dropping it. If your torso swings or your elbows drift forward, the weight is too heavy for strict form.
Is a 50 lb hammer curl good?: Curling a 50 lb dumbbell per arm with strict form is an advanced level of strength that most recreational lifters take years of consistent training to reach, well above what most intermediate lifters use. For most people, a controlled 15 to 30 lb hammer curl with good form is a solid, realistic working weight.
Should beginners do hammer curls?: Yes, hammer curls are beginner friendly, since the neutral grip is easier on the wrists than a standard curl and the movement has a low skill floor. Beginners should start with light dumbbells and focus on keeping the elbows pinned to the torso before adding weight, since forearm and elbow tendons adapt more slowly than the biceps themselves.
What is a common mistake people make when doing hammer curls?: The most common hammer curl mistake is swinging the torso or heaving with the shoulders to move the weight instead of curling with the arms alone, usually a sign the load is too heavy. Letting the elbows drift forward mid-rep is a close second, since it shifts tension off the target muscles and turns the movement into a shoulder exercise.
Are hammer curls for shoulders?: No, hammer curls are primarily an arm exercise, targeting the brachialis, brachioradialis and biceps rather than the shoulders. The shoulders play a minor stabilizing role in keeping the upper arm still through the rep, but they are not the muscles the movement is built to train or grow.