What can you do about an uneven bust? I get this question all the time, and for those who understand—I’ve got you! As your undergarment educator since 2005, I’ve seen thousands of chests and can say with full authority: breast asymmetry is common, normal, and okay. Hurray! 

Busts are like hands and feet—they’re never perfectly symmetrical. There’s nothing wrong with you or your body if your set isn’t exactly even. That said, it can bring up a lot of body insecurities or worries if your set isn’t perfectly symmetrical. And it can also cause discomfort from an ill fitting cup on one side, gapping, or spillage.

So if you want to even out your silhouette and get your best fit with the help of an insert or a bra designed for this exact need, there are plenty of great options. Whatever you decide to do, do it with some hurray! Read below all about how common uneven breasts are, what causes it, and what you can do about it. 

Disclaimer: Psst! Some of the brands linked are proud partners of mine or I may get a small thank you commission if you purchase through me. Your purchase through those links helps a lot in keeping articles like this coming your way. Either way, I always share items that I truly love and can help you say hurray!

How Common Are Uneven Breasts?

Uneven breasts—also known as breast asymmetry—are incredibly common! As a bra fitter since 2005, I have seen a LOT of breasts and chests, and can testify that this is very common. In fact, most people have some degree of asymmetry, whether it’s a difference in size, shape, position, or nipple placement. A study published in Annals of Plastic Surgery found that over 90% of women have some degree of breast asymmetry in volume, shape, or nipple position. And a British Journal of Plastic Surgery study reported that breast asymmetry is considered a normal anatomical variation rather than an abnormality.

Breast asymmetry can be caused by a variety of factors. For some, the difference is subtle, while for others, it can be more noticeable—sometimes by a full cup size or more.

The good news? Uneven breasts are completely normal, and there are plenty of solutions—from fit tips to specialized bra styles and inserts—that can help you feel comfortable and supported. Keep reading to explore your options!

What Causes Breast Asymmetry?

Breast asymmetry can be caused by several factors, so don’t stress! These can range from natural development to hormonal shifts. Here are some of the most common causes:

1. Natural Growth & Genetics

Just like your eyes, hands, or feet, breasts develop independently and at different rates. You know how one shoe fits a little tighter than the other? Or a ring feels different on the same finger on different hands? The same happens with breasts. It’s normal for one breast to grow slightly larger or take on a different shape due to genetic factors.

2. Hormonal Changes

Hormones play a HUGE role in breast size and shape fluctuations. Major life stages that can affect symmetry include:

• Puberty – During adolescence, one breast may develop faster than the other, sometimes taking years to even out, or sometimes they just remain that way.
• Menstrual Cycle – Temporary swelling or tenderness in one breast more than the other is common due to hormonal shifts. Take notice and see if that happens with yours about 1 week or so before your cycle starts.
• Pregnancy & Breastfeeding – This is a super common reason I’ve seen asymmetry in the fitting room. Changes in glandular tissue and milk production can cause one breast to enlarge more than the other, and if your kiddo favors one breast over the other, that can affect its size later on.
• Menopause – A decrease in estrogen will alter a LOT of things in the body, and breast shape and fullness (sometimes unevenly) is just one of those things.

3. Structural & Muscular Differences

The chest wall structure that lives underneath the bust, ribcage shape, and muscle development can all impact the way breasts sit on the body, making one appear higher, lower, or larger than the other. I’ve fit folks with a barrel chest, or scoliosis where the breasts might appear asymmetrical on the body. Sometimes the volume is actually really similar but the placement on each side of the chest is different. 

4. Medical Conditions or Trauma

• Poland Syndrome – A rare congenital condition where one side of the chest and breast tissue develops differently. 
• Breast Surgery or Injury – Surgeries, biopsies, or trauma can impact breast tissue growth and appearance. A lumpectomy or mastectomy is a very common reason for this, but other events are just as possible to affect breast shape or size on one side.
• Fibrocystic Changes & Lumps – Benign (non-cancerous) lumps or cysts can temporarily change the size of one breast. This happened to me! While most lumps are harmless, any sudden change should be checked by a healthcare provider. I got mine checked out and all is well, but it’s always a good idea to be safe. 

Should You Be Concerned If Your Breasts Are Uneven?

In most cases, breast asymmetry is completely normal. Truly. I have seen this in thousands of people! And there is nothing wrong with you or your body. I promise. You are still lovable, worthy, and beautiful whether your breasts are twins, sisters, or cousins. Hurray!

Also, self-care with underwear includes taking care of any potential medical needs. If you notice a sudden change in size, shape, or texture, or experience pain, dimpling, or nipple discharge, it’s a good idea to check in with a doctor to rule out any underlying concerns.

Want to explore supportive solutions for uneven breasts? Keep reading for expert fit tips and shopping recommendations! 😊

What Can I Wear to Even Out My Breasts? 

Great news! We’ve come to the shopping part of this article and I have some GREAT options for you. Listen, it’s always OK to let your uneven bust be just as it is. There is nothing wrong with having an asymmetrical bust! That said, if you want to even out your silhouette, there are several options available these days. You get to choose! From special bras to inserts, below are a few of my favorite solutions to even out your bust. 

A Stretch or Flexible Cup Bra

One of the easiest ways to work with an uneven bust is to wear a cup that will stretch and accommodate both. Bra cups that are made from stretchy mesh, lace, or a flexible molded material like “3D Spacer Molding” are great for this. The entire cup can be stretchy, or even just the top portion where the fullness or shape of the bust is typically more accentuated. This style of bra is especially useful for busts that are just slightly uneven. 

Tip: Always fit your bra to the fullest breast and leave a little extra room in the smaller cup. This way you won’t dig into your fuller side or cause any spillage. You can either tighten the strap a little more to help the cup lie flush, or put an insert into the smaller side. 

The Balanced Bra Company

I have shared this brand many times on my own social media, and in my TV appearances because I just believe in the genius of this product so much! This clever bra brand allows you to purchase a cup size on one side, and another on the other side. For example, you can choose 34D on one side and 34DD on the other, and The Balanced Bra Company will put it together using both a front and back closure. Hurray! 

Check out their various bra styles below and use code KIMMAY10 to get 10% off your order.

Understance

Meet the Symmetry Flex Wire Lightly Padded Demi Bra from Understance. With this bra, you have the option to add in the included, slim pad or your own insert. (See some insert examples below).

This is just one style from their Asymmetry Collection, and I love it. First, the stretch cup really works with your shape—just fit to the fuller bust and leave a little room on the smaller side. You can adjust the cozy, padded strap slightly tighter to keep things flush or slip in one of the included pads to even out a slight difference—or add modesty and shape to both. The stretchy pocket opening can even accommodate your own insert for larger differences.

Bonus features: Flex wire, convertible straps, soft material, and US sizes 30–44, C–H cups.

Wacoal 

The Shape Revelation® Uneven Underwire Bra was especially designed for uneven breasts by this popular bra brand. This underwire bra features straps at the top of the cup with a unique front adjuster that allows you to slightly change the cup coverage for your breast tissue as needed. The stretch cup material also assists each side to fit flush to the bust. It’s a neat concept and a cozy, smooth bra that will work with most outfits! Watch me talk about this on The Today Show.

Inserts and Balancers

Inserts have come a long way from the chicken cutlet style insert, and there are various styles and options available these days! Bra brand, Anita, makes post surgical protheses that can fill out an entire cup, while the styles below are best for evening out slight to a few cup size differences between two breasts. Some are made from lightweight material, others from silicone. Test out the fit and feel for you and see what works best! 

If you’re tired of flimsy inserts that move around, I found a game-changing solution. Read more on Honey Cloudz in the article below.

Additional Uneven Bust Resources

Bust asymmetry can really affect confidence, so it’s an important topic! That’s why I have been talking about uneven breasts in videos and on TV for well over a decade, and have addressed this on Rachael Ray, The Drew Barrymore Show, and The Today Show. Check out the clips and recaps below! 

Free Fit Guide & Video

Want to wear a bra without ripping it off at the end of the day? Watch Kimmay’s video tutorial on getting a comfortable fit, plus a printable guide and checklist to take shopping. Don't spend another minute feeling uncomfortable in your bra.

Your turn:​ Have you struggled with gaping on one side or spillage on the other? Do you find yourself adjusting throughout the day or feeling self-conscious about the difference? And which options are you excited to try?  Share with me @hurraykimmay on Instagram and TikTok!