What you may have heard
Wearing bras causes cancer.
What science tells us
There has been concern that bra wearing changes how lymph nodes remove waste and toxins from the breast. However, there is no epidemiological evidence to support this claim.
The Fred Hutchinson Cancer Research Center in Seattle interviewed over 1,000 women with the most common types of breast cancer and 500 randomly selected women without breast cancer. The investigators found no difference between those who did wear a bra and those who did not (Harvard Health). An earlier Harvard School of Public Health study also found no association when they asked 15,630 women about their bra usage and breast cancer history (Hsieh et al.). These two studies suggest that there is no association between bra use and breast cancer.
Laboratory Evidence/Supporting Evidence
There is no laboratory evidence that links bras to cancer risk.
IARC Carcinogen Classification: Not classified.
How to reduce your risk
There are several known risk factors associated with breast cancer. Drinking alcohol is clearly linked to an increased risk of breast cancer, and that risk increases as the amount of alcohol consumed does. Women who have one alcoholic drink a day have a small (7-10%) increase compared with non-drinkers; this risk increases to 20% in women who have 2-3 drinks a day (ACS).
Another known risk factor is obesity after menopause, or having a BMI of 30.0 or higher. After a woman reaches menopause, most of a woman’s estrogen comes from fat tissue. Excess fat can raise estrogen levels and increase the risk of developing breast cancer. Women who are overweight or obese also tend to have higher insulin levels, which are associated with some cancers. Both of these risk factors may be mitigated with physical activity and a healthy diet, which reduce the risk of breast cancer (ACS).
There is no epidemiological evidence that supports an association between bra use and breast cancer.
Learn More From These Trusted Sources
American Cancer Society (ACS): Lifestyle-related breast cancer risk factors
ACS: Breast cancer risk factors you cannot change
Harvard Health: Breast cancer and bras
Cancer Epidemiology, Biomarkers, and Prevention Journal: Bra Wearing Not Associated with Breast Cancer Risk
Hsieh et al. Breast size, handedness, and breast cancer risk
Published: June 24, 2021
Verified/updated: August 22, 2022