Why Are Your Breasts Two Different Sizes?

By Michael Adeyanju |
|5 min read

Is your right breast bigger than left or vice versa? Most women have probably wondered why their breasts are two different sizes at one point in their life. You might have even been worried about it, thinking it's caused by an illness.

Well, we have good news for you. More often than not, breast asymmetry is perfectly normal. Sure, some conditions can cause one of your breasts to be bigger than the other, but it's usually not a cause of concern. Read on to find out what's causing breast asymmetry and how you can deal with it.

What Causes Breast Asymmetry

"My left breast is bigger than the right; is something wrong with them?" If you've ever asked similar questions before, we have good news for you. Uneven breast sizes and shapes are actually a lot more common than you think. Think of your breasts as sisters, not twins - they look similar but they won't look exactly alike.

Common Causes

Here are some common causes of uneven breast sizes.

Hormonal changes

Hormonal changes can change the volume of your breasts, causing one to be bigger than the other. For example, your breasts will grow slightly near ovulation due to blood flow and water retention. It's common for one side to grow a bit more.

Weight fluctuation

Weight gain and weight loss can change the volume of your breasts. After all, your breasts are mainly composed of fat. Sometimes, the weight fluctuation affects one breast more than the other, causing one side to appear bigger.

Pregnancy and breastfeeding

Pregnancy can also make your breasts appear uneven. Both weight gain and hormonal changes play a huge role here. But, it's not a cause for concern, and they will usually return to normal within a few months after giving birth.

Breastfeeding can also cause breast asymmetry. If your baby prefers nursing on one side, it will become bigger due to more breast milk production and blood flow.


"Okay, but what if my left breast is bigger than my right to begin with?" Well, it means you inherited uneven breasts from your mother or grandmother. Genetics play a big role in determining your breast size and shape. If your mom and grandmother's breasts are asymmetrical, it's likely that yours will be, too.

Medical Causes

Here are some medical conditions that can cause breast asymmetry. With these conditions, uneven breast sizes are often accompanied by other symptoms, such as pain and lumps. If you notice such symptoms, consult your doctor.

Juvenile Hypertrophy

This is a rare condition in which one breast grows significantly larger than the other. It only happens in adolescents during puberty. The cause is unknown, but scientists believe it may be due to hormone sensitivity.

Hypoplastic Breasts

Also known as underdeveloped breasts, this condition causes the breasts to be small, spaced far apart, and very uneven. Another symptom of this condition is large areolas. This condition can be caused by extreme hormonal changes, injuries, or medical conditions.

Atypical Ductal Hyperplasia

This condition affects the breasts' milk ducts, causing them to grow excessively. While this isn't a tumor or cancer, this condition may increase your risk of getting cancer. If you notice any lumps or growth on your breasts, contact your doctor immediately.

Tips to Deal with Breasts with Different Sizes

More often than not, uneven breast sizes are unnoticeable. But if they bother you and make you self-conscious, here are some things you can do to help correct them.

Home Remedies

Follow these easy tips at home to make your breasts appear more even.

Breast massage

Massaging your breasts can increase blood flow and help them even out. Make sure to massage the smaller breast more than the bigger one. Use gentle, circular motions to avoid hurting yourself. Using sesame and flaxseed oil can make this method more effective.


Working out your chest area can also make your breasts look more even and perkier. Focus on upper body exercises, such as chest presses, dumbbell flys, and deadlifts.

Pick the right bra

Make sure you're wearing the right bra to support your breasts and make them look equal. Pick bras that fit your larger breast to avoid pain. Try wearing molded and padded bras to minimize any unevenness.

Warm and cold water therapy

Each time you shower, pour warm and cold water on your breasts alternately to improve blood flow and promote collagen production. First, pour warm water over your smaller breast for a minute, then pour cold water on it for 30 seconds. Do this at least three times. You should see results within a month or two.

Medical Help

If home remedies don't work for you, you can consider getting professional help.

Breast reduction surgery

If you're happy with your smaller breast, consider reducing the size of the bigger one. Contact a plastic surgeon to even out the size of your breasts. Be warned that the side effects of this surgery include scarring, pain, and fatigue.

Breast augmentation surgery

If you prefer the look of your larger breast, then you can consider getting a breast augmentation surgery. Rather than getting a silicone implant, ask your plastic surgeon about doing a fat transfer for a more natural look.

Takeaway Message

Next time you notice your right breast is bigger than your left, stay calm. Try examining your breasts, see if your period is approaching, or if your weight has fluctuated lately. This condition is rarely a cause for concern. However, if you notice any pain, excessive swelling, sores, or secretions, don't hesitate to consult your doctor.



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