What Should I Do If One Arm Is Bigger Than the Other? (Inflammation Or Blood Clot?)

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The reason why one arm is unusually bigger than the other can point to different possibilities like the presence of a dominant hand, single-arm swelling, and tendon injuries. You can quickly identify swelling by associating it with other symptoms such as redness, warmth, and slight pain in your swollen arm. However, searching for the root cause of this swelling is a tad more difficult. Various health complications involving blood clots and inflammatory reactions can be responsible. However, if the problem isn’t health-related, you can easily target balancing your arm size and strength by following single-arm exercises.

Of course, we can’t expect perfect symmetry in our bodies as asymmetry is a part of nature.

It’s normal to notice that one arm is bigger or longer than the other, just as it’s normal with other body parts like legs too.

In most instances, the difference is extremely subtle that it goes unnoticed.

You can only work on fixing this difference if it’s related to arm strength imbalance or body complications that lead to swelling of a single arm.

Why is one arm bigger than the other?  How can you know if your arm is swollen? What causes single-arm swelling? How can you treat a swollen arm? How can you balance the strength and size in both of your biceps?

Why is one arm bigger than the other?

A young man who's working out is looking at his arms and wondering why one seems bigger than the other

Our physique can often trouble us since we live with and experience everything with our body for quite a long time.

Before we look into treating our arm, we need to figure out what exactly is wrong with it, and here’s a list of possibilities.

  1. Dominant hand – This is the most typical and apparent reason for this size imbalance. If you’re a right-hander, you’ll notice that your right hand is a little bigger since carrying out daily activities with your right arm will automatically give it more exercise. The same goes for left-handers, who’ll notice their left hand is bigger.  
  2. Arm swelling – Underlying complications in your body can trigger the swelling of a single arm in certain instances. If you notice that your arm is unusually larger and if the skin texture seems different from your other arm, you’ll have to visit your doctor.
  3. Tendon injury – If you’ve recently gone through an accident and you feel a certain imbalance in your bicep, chances are that your tendons haven’t healed properly. Sometimes such an injury can even occur during daily workouts, and you can clearly notice this size difference, especially when you’re flexing.
  4. Improper workout form – Maintaining the exact training form is important. A simple error in your form would mean that you’re letting your other body parts do all the work instead of the area that you’re intending on working out.  

How to know if your arm is swollen?

When you notice one arm is bigger, the way to exactly pinpoint that the cause is swelling is quite easy.

You’ll always experience other symptoms as listed below, along with the swelling.

  1. Mild pain – A specific heat and slight pain caused by an increased blood flow can be felt by you.
  2. Discoloration of the skin – Especially when your arm swells due to a bruise, you can sense a certain purple or yellow color on your arm. Such bruising can occur from an injury to either your bicep or tricep.
  3. Tingling fingers – This occurs in one hand when a nerve has been tightened in between two bones or muscles.
  4. Skin texture – Redness and warmth in your arm area that’s bigger would undoubtedly hint at swelling.
  5. Difficulty in movement – Apart from the change of mere looks in both your arms, if you’re going through difficulties in carrying out your daily activities due to a certain stiffness and inability to move one arm, chances are that it’s swollen and in need of medical attention.

What causes single-arm swelling?

Out of the four possibilities, the one that you should be most concerned about is single-arm swelling.

A woman is feeling swelling pain on her left arm after working out

Since only one arm has swollen, you can cross off any systemic diseases since such diseases affect other parts of your body as well.

So, what we’re then left with is clearly shown in the following table.

Health conditionWhat it means
Vein complicationsBlood clots in your deep veins, known as thrombosis, can cause swelling in your arm. If the large subclavian vein near your neck gets compressed too, you might notice arm swelling as a symptom.
Inflammatory reactionsWhile arm swelling after vaccination is normal and nothing to worry about, swelling due to allergies and insect bites could require medical assistance if it doesn’t go down.
Lymphatic complicationsAny kind of damage to your lymphatic drainage system can make lymph fluid collect up. This can be caused by infections, tumors, and lymph node-based surgeries.
OsteomyelitisThis is also known as chronic upper arm bone infection. According to the US National Library of Medicine, 50,000 cases are reported annually, which means it’s not so common.
Benign bony growthThis is a very rare condition that develops either when you’re a child or in your adolescence. This involves a benign tumor that takes shape on the upper surface of a bone. X-Ray procedures are required to confirm this condition.

How to treat a swollen arm

While it’s true that you need to know what your medical condition is, for precise treatment, when it comes to swelling, there are specific home remedies that you can try out.

Pain medications like ibuprofen can help out any physical pain with your swelling.

Apart from this, you can treat your swelling and any itchiness to inflammatory reactions by taking antihistamines.

If your swelling results from arm overuse or injury, you’ll have to take lots of rest and try using a cold compress.

According to a 2010 study conducted by the US National Library of Medicine, cold compression therapy was said to directly relieve swelling and inflammation. 

If blood clots are causing this whole dilemma, medication is mandatory.

Anticoagulation medication helps treat arm clots, and various other medicines also exist to help break up blood clots, such as thrombolytic.

In certain instances where swelling has occurred due to tendon overuse, surgery might be the best option there is to take. 

How can you balance the strength and size in both your biceps?

If the problem with your arm size has nothing to do with the body and internal complications, chances are that one of your biceps isn’t receiving the same workout as the other.

Here is a list of things you’ll need to consider to restore the balance of strength in both your biceps:

  1. Unilateral workout – You can even out your biceps by simply working on the bicep that’s smaller in size. This means that it’s time to replace your barbell curls with dumbbell curls to give more focus to single-arm exercises.
  2. Resistance bands – These bands are not only ideal for strength building in one arm, but it also helps to improve your mobility and flexibility within your upper body.
  3. Dumbbell balance – By using heavier dumbbells for your underdeveloped arm, you can carry on with your usual workout process without needing to provide too much attention to one single arm.
  4. Repetition – Try doing repeated weight lifting exercises for your smaller arm with a lighter weight. This will help increase the blood flow to your muscles while helping build mass and strength


As explained, various exercising options are available to fix the arm size imbalance.

Workout techniques such as engaging yourself in concentration curls, lying cable curls, and single-arm reverse cable curls exist solely for this purpose.

You can easily aim at fixing this problem at the gym or even at home, given that you’ve got the correct equipment.

However, if you’ve sensed any kind of single-arm swelling according to the symptoms we have listed, you’ll need to visit your doctor to properly diagnose the condition, because self-diagnosing can only do so much.

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Kavisha Rodrigo
I'm a sports person that enjoys researching into pushing the limitations of the human body. When it comes to health, I'm a big fan of working out and staying healthy. For hobbies, I'm a big fan of Pokemon and Coldplay.

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