Asymmetrical Pectorals

Alright… At 17, with a very lean, ectomorphic body, I became sick of being 6’1" and 150 lbs. - so I began heavy lifting with an altered diet.

…And already: rapid growth. It’s beautiful!

However (and I’m sure everyone saw this coming), I had some Polaroids taken of my body so I could pinpoint areas that need “extra assistance,” and I saw something that really bothered me: my left pectoral is less developed than my right.

Now, I’ve come up with all sorts of theories to explain this. The one that really sticks out in my mind, though, is this: all those push-ups and fooling around with weights when I was young and in gym class - having no concern with concepts like “good form” and “cheating” - led me to squirm and twist and finish that rep with my dominant, right arm/pec doing most of the work. So, as one might assume, my left pec ended up literally smaller than my right. And not only is there a difference in size, but definition as well: while I have virtually no visible upper-pectoral on either side, the lower pectoral of my right side is very well defined while my left side remains, well… very “smooth” and underdeveloped.

Obviosly this is a problem I'd like to correct, and that's why I'm posting this message: I'd like to see what everyone thinks. I was thinking of doing all my future pec work with dumbells, so as to force each pec to do its own duty, while maybe even increasing the weight of my left arm's dumbell a slight 5 lbs. or so. My common sense tells me that this will stimulate more growth in my left pectoral, therefore "evening out" my look. I would base my weight and estimate my repitions all around the left dumbells' weight, so as not to cause any damage. But, then again, I've never heard of anyone else doing something like this before (not to mention someone with this problem before), and the last thing I want to do is dig myself deeper into this situation.

Any comments or suggestions would be immensly helpful… and I know this is a weird question ;).

Thanks, everyone.


Dumbells will help, but you need to back off a bit and have some one help you with your FORM first, then let the weak side dictate the load and reps. It will eventually catch up. Don’t try asymmetrical loading, just let the weak side dictate. Make sure your form is good and even (both shoulders staying all the way back on bench), then start increasing the load.

Dan, its not a weird question, and LOTS of people have this problem, as no one is perfectly symmetrical. My left pec is considerably larger and more powerful than my right, and in my case it’s probably due to genetics (my left pec actually appears to insert deeper into my sternum than my right). The disparity is so great that, once, after taking a while off, I loaded up a barbell and began my lift only to watch the left side of the bar rise while the right remained stationary (imagine a teeter totter). Luckily, my spotter was on the ball.

You might try dumbell presses and alternate reps between both sides (i.e. one rep on only the weak side, then both, then only the weak side, etc.). Also, don’t sweat not having perfect symmetry. Unless it’s extreme, chanses are no one will notice.

I have the same problem, and I really hate it. Lately I’ve been using dumbells but my left pec comes away more sore than my right which angers me further.

just stick to db presses(slight decline are best) DON’T use more wt. on week side and DON’T do more reps with week side, just let the week side determin how many reps and how much wt. to use. EVERYONE is asymetrical (the inside of my left pec is kinda flat) just get big and no one will notice(atleast if they do they won’t say anything!)

I have a similar problem in that I was born with the right side of my rib cage actually curving in, and the left is normal(curves out). One of the main reasons I started working out was to try and correct the problem and I have almost built the right side up to the left. I do machine fly’s with my left arm stationary and work these in between other body exercises. So I’d do a set of curls and then hit the peck deck doing only the weak side. Hope this helps.

I believe there is an article in the T-mag archives that addresses this situation…it may have been a question and answer column. I believe they recomended doing slightly more volume on the weaker side…you yourself said you think the larger side became larger due to a greater workload.

I think switching to DB’s is only part of the solution to this very common problem. I think one must look to the neck and rotator cuff musculature in order to truly fix this problem. My guess is that for some unknown reason, the muscles around your weaker shoulder have become dysfunctional. Simply put dysfunctional means that the muscles are not healthy. They may be in spasm, have inter and/or intra-muscular adhesions and almost always they have an inreased density and trigger points. The best way of fixing this is going to a massage therapist, physical therapist or chiro and have them assess the musculature of your left shoulder/neck (levator scapula, teres minor, infra/supra spinatus,etc…) and do some soft tissue work on the dysfunctional areas. This should be a moderately painful experience if its done right! After massage the clinician should show you various strength and flexibility exercises to help restore function in the problem areas. For this reason I suggest going to a good sports PT but you will probably get a shorter massage. I have found great success at improving right/left assymetries with this protocol rather than merely switching to DB’s. This has a lot to do with “structural balance” that Poliquin has mentioned in an earlier Tmag article. I would bet that many of the people above who have tried to fix their immbalance by doing DBs and unilateral exercise without addressing the dysfunction have had less than satisfactory results. I say this because I’ve seen many people (myself included) struggle for years to fix this problem with modified strength training only to get frustrated.
Mark C

Ok, the guys at the gym and I discussed this and we concluded that you are one half of a set of Siamese twins. You and your brother were joined at the chest and separated at birth. Due to a mixup at the hospital they gave him to another family. What you need to do is find him and get the other half of your chest back :slight_smile:

hetyey225, any reason in particular you don’t think the increased volume on one side is a good idea?

I have the same problem Big Chief has and as I continue to develop it has become less noticable in the pecs but still just as noticable on the top of my abs. I just live with it, as I said it became less apparent down the road.

Demo, because volume DOES NOT WORK. all that will happen is you will over train that side of your chest, lets even say that somehow it would work (it would not but lets just say) then Isn’t your one delt and your one tri going to grow out of proportion to the other side( especially because benching on flat or incline is more a delt exercise anyway)?


I have always had a weaker shoulder: I believe it was inherited from my mother. She went to physical therepy for a year or two after her arm began to go numb in her sleep. What I’m saying is: what you mentioned really struck a nerve with me… maybe my shoulder has something to do with it… I hadn’t even thought about it up until now. If you could further explain to me - in as simple terms as you can - what the physiological reasons are behind a weak shoulder influencing the growth of the adjacent pectoral, it would really ease some of my anxiety about this whole thing (it appears it may be more complex/serious that I had originally thought). Thanks ahead of time.


And to everyone else up there: Thank you very much! You’ve all been such a great help.

(I love this place…)