How To Slim Down A Muscular Upper Body

how to slim down a muscular upper body

I have talked a lot about how to slim down thighs and calves, but haven’t talked too much about how to slim down a muscular upper body.

This is because most complaints I receive are about legs, but also most women don’t seem to bulk up in their upper body like they do with their legs.

But in saying that, all of us are different, and I had a request for this blog post, so I know it happens to some of us.

I have also experienced my upper body bulking up with too much heavy lifting and CrossFit.

My arms themselves didn’t become that much bigger, it was more my back. My back got really broad and my crop tops and shirts became really tight around this area.

So if the same thing has happend to you too, read on to find out how to reduce a muscular upper body.

You’ll learn what exercises to avoid, and what exercises you can do to tone them up without getting bulky.


Reducing any muscle takes time and requires you to not use these muscles, to give them a chance to reduce in size (or “atrophy”).

If you continue with heavy lifting or whatever exercise it is that bulked you up in the first place, you will never reduce this muscle. Stopping this type of exercise is the most important thing.

I know giving up intense exercise and heavy lifting can be difficult at first, but there are lots of other exercises you can do (see below).

You can speed up the process by eating at a slight calorie deficit (and I really mean slight) and eating a low carb diet.  These things will help you lose weight and muscle.

But it’s extremely important that you don’t starve your self. That will just slow down your metabolism and it may have serious consequences on your health. 


Obviously, you need to stop doing the exercise/s that have contributed to your bulkiness. That is number one.

In my experience, the exercises that make your upper body too muscular include:

  • Overhead pressing exercises such as barbell shoulder press; and
  • Overhead pulling exercises, especially chin-ups and lat pulldowns.

Any overhead pushing / pulling motion will make your back broader, which might be an issue for you, as it was for me.

These exercises are used heavily in CrossFit, so if you are doing CrossFit and are getting too muscular for your liking, I would stop.

I would also avoid all heavy lifting and workouts focusing on strength. By this, I mean lifting anywhere in the 3-8 rep range. And also avoid any isolation exercises such as bicep curls.

how to slim down a muscular upper body


I would also highly recommend you to find out your body type. This is super important since different body types lose weight and build muscle differently.

 I’m a mesomorph body type which means I’m quite athletic and I can gain muscles quite easily. I didn’t know my body type when I started getting into fitness but if I knew, I could’ve saved myself much trouble.

If you are not sure about your body type, you can take my Body Type Quiz. It will help you learn your body type in just 2 minutes and it’s completely free. :)


Doing some form of resistance training is still important and will make your upper body looked toned. Also, resistance training is great for raising your metabolism which means it will be easier for you to lose weight.

So you can’t skip it.

These are some workouts you can try that will help tone up your upper body without getting too muscular. Also, a lot of them are great for your core too!


Boxing is my favourite workout for toning up your arms without adding bulk.

It tones them up really fast, and you only need to do 1-2 classes per week to notice a difference.

If you can’t get to a class, try making up your own little circuit at the gym (if it has boxing gloves and a bag), or doing a Les Mills Body Combat class at home.

how to slim down a muscular upper body


Swimming is also really great for toning up your arms without increasing their size.

I know professional swimmers having really broad shoulders, but they do train ridiculously hard, which is why they have this shape. If you just swim 30 minutes 1-2 times per week, this won’t happen to you.

When I was triathlon training, all I did was swim, cycle and run.

My arms were super toned and I wasn’t doing any resistance training for them. I was just swimming 2-3 times per week for 30 minutes. So I know it works :)


You don’t need to avoid resistance training all together. I would just avoid anything heavy as I mentioned and anything low rep (3-8 rep range).

I have posted a free lean arms workout on my blog, so have a look at this to give you an idea on some circuits you can do.

Otherwise, I have posted a few free workouts from my  3 Steps to Lean Legs program.

These are all full body so they will work your arms and core, as well as your legs. And it will give you a good idea on some exercises you can do that will tone up, but won’t cause bulkiness.


HIIT workouts are great for toning up and a lot of women don’t have issues with HIIT bulking up their upper body.

HIIT workouts are usually very leg focused and they can cause your lower body to bulk up.

So I would avoid too many lower body exercises and avoid too many shoulder pressing exercises. Here are a few examples of HIIT workouts that won’t bulk you up.

A lot of core workouts also involve being in the plank position, and this is great for your shoulders and upper body too!


Pilates is a great form of lighter resistance training that will tone up without adding bulk.

You can do regular pilates or reformer pilates – both are great. They use light weights, pilates rings or just body weight only.

As always, if you have any questions, please feel free to ask me :) I hope you found this helpful! xx

Picture of Rachael

Rachael is an Australian born certified personal trainer and nutritionist who holds a Bachelor degree in Science.

After struggling for years to find an exercise and diet program that is tailored to women striving for lean and toned body with no bulk she designed her Lean Legs Program. This program is tailored to each body type and focused on helping women get toned but feminine bodies, without getting bulky.

Her mission is to empower women and help them stay in shape in a healthy and balanced way.

55 comments on “How To Slim Down A Muscular Upper Body”

    a says:

    Hi there I ended up gaining a broad upper back and bigger arms through swimming, any anther suggestions besides not exercising my upper part?

      Diana - Lean Legs Support says:

      Hi lovely,
      I would recommend boxing as it’s really good for making your upper body lean and toned. You should also eat at a small calorie deficit (200-300 calories less than you burn) in order to reduce the muscle mass.
      Here are some great upper body exercises that won’t make you bulky:



    Lia says:

    Please, if you’re reading this remember that if you’re doing something you enjoy and you get more muscular, it’s okay.
    Muscular bodies are okay.
    Life should be about enjoying things. Do what you wish but remember you done have to do anything because of what others think. You are beautiful as you are.

    Eunice Henry says:

    Hi Rachel, I have problem with my arms. It’s too bulky and muscular. Please help me and guide me on how to decrease or lose the muscle in my arms. I have been struggling for 2 years.

      Diana - Lean Legs Support says:

      Hi lovely,
      The best way to decrease muscle in your arms is by reducing your overall muscle mass. I’ve found that swimming and boxing are particularly good for slimming down the arms (both fat and muscle)! :) xx


    Brooke DeVore says:

    Hi, I had been doing pilates on a megareformer machine for 5 months now, and the backs of my arms have gotten significantly larger. I used to have very small arms, and this new mega reformer workout is the only workout besides walking that I have done in those past 5 months. We do a lot of pushups in the class. People have made comments about how my arms look muscular now, when they used to look lean.

    Is there any way to slim the backs of my arms in 2 months? I get married in 2 months and am scared that if I do any kind of weight lifting in my arms they will stay as big as they are, but if I don’t do anything, will my arms get bigger because the muscle is not being worked at all?

      Diana - Lean Legs Support says:

      Hi lovely,
      I think the best way to slim down your arms is to reduce overall muscle mass. You could take a break from doing push ups and exercises that build your arms and focus on light intensity cardio instead.
      Boxing is a great exercise to tone up your arms without getting bulky, and also helps tone up your core too. :)

      Wishing you all the best! xx


    Jerrrine says:

    I have really big and muscular arms right now. And would doing the above exercises help? Because i’m worried if I keep doing hiit and boxing and etc it will only become bigger :-(

      Diana - Lean Legs Support says:

      Hi lovely,
      Feel free to do these workouts, they’ve been designed to help you slim down without bulking. I would actually recommend boxing to slim down your arms, but I would avoid HIIT if you gain muscle easily.


    Jeannine Cotogno says:


    Jeannine Cotogno says:

    This happened to me with Crossfit as well. Clothes don’t look good. Shoulders and back become extraordinarily out of proportion I never did over head pressing Bc it’s a building exercise. And in cf it’s alk building. I need to go back to shaping and with light weights. I’m only 5’1 I feel like a linebacker. Thanks I know I’m not alone

      Diana - Lean Legs Support says:

      Hi lovely,
      You can also do bodyweight exercises to slim down, you don’t necessarily need weights for upper body exercises. Also, boxing and swimming are great workouts for your arms and shoulders! xx


      jasmin says:

      You’re not alone! I’m 5’3″ and I hate wearing tight tops or short sleeves because my arms and shoulders are so bulky!! Thanks to crossfit and bikini competition training.. I’m left with these huge arms/shoulders and a thinner body. It’s very discouraging and I feel out of proportion. I just gain muscle quickly, but got to get rid of these arms! Good to know there are other out there.

    Soni says:

    Interesting. But what do you mean with avoiding all heavy weight exercises? I wanna grow my lower body. So I have to lift heavy in many exercises. Did you mean that even squats or dead lifts, that barely touch my upper body, affect it anyway? Or just you were referring to exercises for upper body?

      Diana - Lean Legs Support says:

      Hi lovely,
      If you’d like to gain muscle in your lower body you should keep lifting weights. Squats and dead lifts are also great for your core and will make your abs more toned! :) xx


    Nikita says:

    Thank you so much for this article. I’m tired of reading, “Lift heavy, you don’t have enough Testosterone to bulk up”. Though I know that’s true, my BMI indicated my lean mass as excess for my arms. My arms also look “bulky”. This article restores some faith after all the hard work and disappointing results.

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