My Right Arm is Bigger Than My Left Arm – What to Do?

Right-handed people have larger right hands while left-handed people normally have larger left hands. The dominating hand is normally larger as it recruits more muscles with daily tasks.

Both your right arm and your left arm can be bigger, depending on your dominant arm. Differences in arm size are normal. Muscle imbalance differences can even out by lifting weights or by doing more with the weaker arm.

Why is your right arm bigger than your left arm?

Hemihyperplasia describes the condition in which one part of the body is bigger than another. A leg can be larger than another leg or an arm can be larger than another arm in this condition.

However, this is not the case of your right arm being bigger than your left arm or your left arm is bigger than your right arm. It’s mostly an issue of activating the muscles in your dominating hand more.

What should I do if one arm is bigger than the other?

Muscles can be worked to gain size. Both the right arm and the left arm can get bigger. You can train your left arm to be bigger and in time, muscle imbalances between arms diminish or go away completely.

Work arms individually

You need to work arms individually, to begin with. This means no more biceps curls with the EZ bar or with the Olympic bar. But why would you not train your arms together when you want them to have the same size?

The dominant hand might take over and pull/push more weight when training both arms at the same time.

This is why you should start doing biceps curls and triceps extensions with the same weight, but with one hand at a time.

It’s best to start with the weaker or smaller hand first. Your left arm can be smaller and you need to start exercising it first. The number of repetitions you can do with the weaker hand is the number of repetitions you will do with the dominant hand. Great exercises to fix muscle imbalances in the arms.

  • Biceps curls
  • Triceps extensions
  • Dumbbell wrist extension
  • Reverse curls
  • Hammer curls
  • Farmer walks
  • Dumbbell shoulder presses

Don’t work both arms at the same time

Together with training arms individually, you need to reduce or eliminate exercises that work both arms at the same time. This includes Preacher curls and even barbell rows.

Start training the weaker arm first

Always start training your weakest arm first. When you take sets to failure you’ll notice you can do more repetitions with your stronger arm. This should be avoided.

Have the muscle-mind connection when training

Training with good muscle-mind connection has been debated on the web thousands of times, there’s no point going into detail about it. However, you should actively have your mind connected to how your arms are activated during exercises and not simply going through the motion. Even slowing down the tempo for each exercise can considerably improve your results.

Try doing more tasks around the house with the weaker arm

Another very good option of evening out muscle imbalance and your right hand being larger or your left arm is larger than your right arm is to do more around the house with the weaker hand. is all about home living. Why not try using power tools with your weaker hand? Sure, this doesn’t mean holding a chainsaw with your weaker hand. But you can use screwdrivers with your left arm as well as all types of small power tools which aren’t dangerous. Instead of doing biceps curls all day you can fix up that fence, paint the garage, or refinish the patio using power tools you hold with your left arm.

We explore cheap options in our Ridgid vs Ryobi comparison post. These power tools are certainly cheaper than dumbbells and you might even fix your muscle imbalance without overspending. Another method to cheaply fix this imbalance is to make your concrete weights and train in your home gym.


Given you have no medical condition which would require you to see a doctor you can fix your right arm being bigger than your left arm. Small daily changes can help, but you will need to have the will to do these changes and work more with your left arm.

This can be a simple task such as carrying groceries or opening the car door. The more you will do with your left arm the stronger and the larger its muscles will get.

You can also try doing other nominal chores around the house with your left arm first. You can carry firewood, stack up shelves, garden, and even cook more using your left hand. All of these small tasks eventually help you get back on track and avoid having one arm larger than the other.