why is my left arm bigger than my right?

My left arm is about 3/4 inch bigger than my right, yet I am right-handed. You might not think 3/4 of an inch makes a difference but it does. my tricep on my left arm is easy to see yet I can hardly even tell that I have one on my right. Why is this happening and how can I correct it?

There was a similar question answered by, If I recall correctly, Poliquin, some time ago. I dont know how to guide you thier though. But is your left arm stronger as well or is it just bigger in girth?


I have the same problem, if it’s one. I’m a lefty and my right arm is bigger, but weaker. When people want to feel my arms, I always show the right one. But frankly, I don’t give much of a shit!

That’s pretty common. Most people aren’t perfectly symmetrical. You just need to start doing one limb at a time training with dumbells or cables. Do your smaller arm first, with your other arm only do as many reps as you did with your weaker arm.

First test out your external rotators. Try using the test in the structural strength article by Charles Poloquin. Make sure you are of equal strength on each side. Then try some seated high pulls with a rope. Do a rep-out set. Have someone watch to make sure you have symmetry throughout the whole set in form and tempo (from back: have them chech shoulders and elbows). If you don’t have symmetry you may be compensating with your strong side. If stabalizers are a problem, drop the intesity and concentrate on slow tempo and fairly high time-under-tension (stabalizers are usually mainly slow-twitch composition). If the stabalizers are not the problem, then move on to primary movers. Try using only dumbells for about a month using slow tempo and a hypertrophy mentality. Make sure you have perfect symmetry. If you don’t - stop. It probably means the weak arm is fatigued and the strong arm isn’t. If you lift continue to lift without symmetry. Your problem with not be solved.

Nick, I have the EXACT same problem as you. I wrote Ian King about this, and he responded that due to my sport involvement which relies much more so on the right side of my body, I probably had a neural impingement in the traps because of tight lats and/or chest. So I started a very intensive stretching routine and its helped a lot. After about five months now, the difference is almost unnoticeable. There was also a suggestion to work the traps before arm training. I tried this last time I worked the guns, and it did actually help a little. I got a pump a little easier. So try that too…

This is funny as I just talked to TC about my problem like this. I’m right handed, and stronger (only slightly though, not appreciably) with my right hand. However, the long head of my left bicep is shorter than the long head of my right bicep. Therefore my left bicep is bigger (1/4 inch) than my right, it has a better “peak” than my right. Wild, wild stuff.