Yes, doing bicep curls one at a time—known as unilateral curls—can offer unique benefits over performing them with both arms together (bilateral curls). Choosing the right technique depends on your goals, fitness level, and need for muscle balance. In this guide, you’ll learn exactly when and why to use single-arm bicep curls, what the research says in 2025, and how to get the best results for your arms.
Mastering bicep curl form is crucial for maximizing muscle growth and minimizing injury. This article explains the key differences, benefits, and best practices—plus recent scientific findings—so you can make the right decision for your workouts.
What Are Single-Arm (Unilateral) Bicep Curls?
Single-arm or unilateral bicep curls involve lifting a dumbbell with one arm at a time, instead of both arms simultaneously. This approach requires more stabilization, can fix strength imbalances, and often delivers a better mind-muscle connection.
- Corrects muscle imbalances
- Increases focus on each arm
- Enhances core engagement
- May improve contraction and peak tension
According to Men’s Health (2025), unilateral training is especially effective for developing symmetry and balance in the arms.
Are Bicep Curls One at a Time Better for Muscle Growth?
Both single-arm and double-arm curls can build muscle equally well, as long as total workload is matched.
A 2024 systematic review published in the Journal of Strength and Conditioning Research found no significant difference in hypertrophy (muscle growth) when comparing unilateral and bilateral bicep training, provided the same overall volume and intensity were used. [source]
Why Choose One Style Over the Other?
- Unilateral curls:
- Ideal for fixing arm imbalances
- Increase core and grip engagement
- Help avoid “cheating” or using momentum
- Enhance mind-muscle connection
- Bilateral curls:
- More time-efficient
- Useful for overall strength and mass
- Convenient for busy gym sessions
As explained by the American Council on Exercise (2024), using both variations ensures balanced arm development and peak performance.
Strength Gains: Which Is Superior?
Bilateral curls are better for building overall strength in both arms at the same time, while single-arm curls improve strength in each individual arm.
Research shows that the “principle of specificity” applies: If you want to be strong at one-arm lifts, train one arm at a time. If you care more about two-arm lifts (like barbell curls), stick with bilateral training. [ResearchGate Meta-Analysis, 2025]
| Curl Style | Best For | Time Needed | Imbalance Correction | Core Involvement |
|---|---|---|---|---|
| Unilateral | Balance & focus | More | Yes | High |
| Bilateral | Efficiency & max load | Less | No | Low |
Functional Benefits and Athletic Performance
Single-arm bicep curls help:
- Correct muscle imbalances between dominant and non-dominant arms.
- Enhance core strength due to stabilization needs.
- Improve coordination and balance for athletic activities.
- Promote injury prevention by strengthening both sides equally.
Unilateral exercises are recommended by coaches for athletes and those recovering from injury (Verywell Fit, 2024).
Is One Style More Time-Efficient?
Bilateral curls are more time-efficient because both arms work together, cutting your total rep count in half. If you have a busy schedule or want to move quickly through your workout, choose double-arm curls for convenience.
However, if you want better quality reps and don’t mind spending a few extra minutes, single-arm curls can pay off in the long run with better muscle balance and peak contraction.
Recent Research & Policy Updates
- Latest studies confirm both methods are safe and effective.
- Fitness authorities like ACE and Men’s Health have NOT changed their guidance in 2025.
- Leading trainers recommend mixing both styles for the best results.
- No major price or equipment changes for basic dumbbell training.
For detailed form tips and updated research, check the ACE bicep curl guide.
Real-World Example: When to Use Each Style
If you notice one arm is weaker, smaller, or “lags” in curls:
- Focus on single-arm (unilateral) curls for 4–6 weeks.
- Track progress—most people see improved balance and strength.
If you want quick, efficient upper body workouts:
- Use both arms at the same time for your main sets.
- Finish with a set or two of unilateral curls to check balance.
Frequently Asked Questions
Can I Alternate Arms During Bicep Curls?
Yes! Alternating dumbbell curls blend both methods and are a great way to challenge your grip and balance.
Will One-Arm Curls Make My Biceps Uneven?
No. In fact, they often FIX uneven biceps by allowing you to work each arm independently.
What Equipment Is Best?
Any adjustable dumbbell or cable machine works for both single and double-arm curls.
Do Celebrities or Athletes Prefer One Method?
Most combine both styles to maximize results and avoid plateaus. Variety is key for long-term progress.
Conclusion
The best approach is to use both single-arm and double-arm bicep curls in your weekly training.
Single-arm curls offer balance, focus, and functional benefits, while double-arm curls save time and build strength efficiently. For best results, mix both types into your program, monitor your progress, and adjust based on your goals.