Hammer Curls: Build Thick, Powerful Arms
Hammer curls use a neutral grip that shifts emphasis from the biceps to the brachialis and brachioradialis. These muscles push the bicep upward and thicken the forearm, creating the appearance of larger, more complete arms.
Proper Form
Stand with feet shoulder-width apart, holding dumbbells at your sides with palms facing your body (neutral grip).
Keep your elbows pinned close to your sides throughout the entire movement.
Curl the dumbbells up by flexing at the elbow, maintaining the neutral grip the entire time.
Squeeze at the top for a 1-second hold, then lower slowly (3-4 seconds) to full extension.
Keep your torso completely still; do not swing or lean back to lift the weight.
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Hammer Curls on GLP-1 Medications
Hammer curls are an underrated exercise for GLP-1 users building arm strength during weight loss. While standard bicep curls work the bicep peak, hammer curls develop the brachialis (the muscle underneath the bicep) and the brachioradialis (the main forearm muscle). This creates thicker arms when viewed from the front and improves grip strength, which carries over to every pulling exercise in your program. Include 2-3 sets of 10-15 reps alongside standard curls for complete arm development. The neutral grip is also easier on the wrists than supinated curling.
Variations
- 1Cross-body hammer curl (curl across your body toward opposite shoulder)
- 2Incline hammer curl for a greater stretch
- 3Rope hammer curl on cable machine for constant tension
- 4Alternating hammer curls (one arm at a time)
- 5Seated hammer curls to eliminate momentum
Hammer Curls vs. Bicep Curls
Standard bicep curls with a supinated (palms up) grip maximize bicep brachii activation, particularly the short head, creating the peaked bicep look. Hammer curls with a neutral (palms facing each other) grip shift significant work to the brachialis and brachioradialis. The brachialis sits underneath the bicep and, when developed, literally pushes the bicep upward, making it appear larger. The brachioradialis adds thickness to the upper forearm. For the most complete arm development, include both curl variations in your program.
The Brachialis: Your Secret Arm-Size Muscle
The brachialis is a pure elbow flexor that sits between the bicep and the humerus bone. It is responsible for approximately 50% of elbow flexion force. Despite being invisible when the arm is relaxed (it hides under the bicep), a well-developed brachialis significantly increases overall arm circumference. It is the "secret" muscle that separates good arms from great arms. Hammer curls and reverse curls are the two primary exercises that target the brachialis effectively.
- The brachialis provides roughly 50% of elbow flexion force
- It sits under the bicep and pushes it upward when developed
- Best targeted by neutral grip (hammer curls) and pronated grip (reverse curls)
- Responds well to moderate weight and higher reps (10-15 range)
Programming Hammer Curls
Include hammer curls in your arm training 2-3 times per week. Pair them with standard bicep curls in a superset: do a set of hammer curls immediately followed by a set of standard curls. This hits all the major arm flexors in one efficient pairing. Use 3 sets of 10-15 reps with a controlled tempo. The cross-body variation (curling the dumbbell across your body toward the opposite shoulder) adds a slight rotation that increases brachialis recruitment.
Muscles Worked
Exercise Disclaimer
This content is for informational purposes only and does not replace professional instruction. Consult a qualified trainer or healthcare provider before starting any exercise program. Individual calorie burn varies based on fitness level, intensity, and body composition.
Frequently Asked Questions
Yes, hammer curls still work the biceps, but with reduced emphasis compared to standard supinated curls. The neutral grip shifts significant work to the brachialis and brachioradialis while maintaining moderate bicep involvement. They are a complement to, not replacement for, standard curls.
Neither is better; they target different muscles. Standard curls emphasize the bicep peak (short head). Hammer curls emphasize the brachialis and brachioradialis for arm thickness. Include both for complete arm development.
Most people can hammer curl slightly more weight than standard curls because the neutral grip allows the brachioradialis to contribute more force. Use a weight that allows 10-15 controlled reps with no body swing. For most men, 20-40 lb dumbbells; for most women, 10-20 lbs.
Both work well. Alternating (one arm at a time) allows slightly more focus and a heavier weight per arm. Simultaneous (both arms together) is more time-efficient and provides a greater cardiovascular stimulus. Alternate between both styles across sessions.
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