Bras can be uncomfortable sometimes. There’s no doubt in denying that; but to what extent are they actually harmful to women’s health?

For example, some people believe that bras constrict blood flow as well as lymphatic fluid flow in breasts, which can lead to a number of health problems, including breast cancer. There are a number of articles online that claim bras cause breast cancer, but the accuracy of these so-called “studies” and medical anthropologists who decry the use of brassieres is rather unclear.

Most high-ranking medical institutions, like the American Cancer Society (ACS) and the Susan G. Komen Foundation, have dismissed the bra-cancer connection as a myth with little to no scientific backing whatsoever. Despite their dismissals, however, no one has stepped up to undertake a more in-depth empirical study investigating this claim — perhaps because they feel as though there’s no point in entertaining this notion at all. But that’s not stopping certain proponents from spreading their beliefs online.

Now, medical anthropologists Sydney Ross Singer and Soma Grismaijer are boycotting Komen and the ACS, declaring that covering up information about the ill effects of brassieres is causing thousands of deaths from breast cancer each year. The couple, who penned the book, Dressed To Kill: The Link Between Breast Cancer and Bras, believes that women who wear bras all the time are 125 times more likely to develop breast cancer than females who never wear bras, or rarely wear them. Women who wear bras only during the day, meanwhile, have a lesser chance of developing breast cancer, but not as small as those who go bra-less, these authors claim.

Grismaijer and Singer have completed research on the subject, published in the American Naturopathic Medical Association (ANMA) journal. Naturopathy is a form of alternative medicine teetering on the edge of pseudoscience, often rejecting the use of modern surgery and drugs, so their claims should be taken with a grain of salt.

The Komen Foundation, meanwhile, has mentioned the bra connection on their page, “Factors That Do Not Increase Risk” of breast cancer. “Scientific evidence does not support a link between wearing an underwire bra (or any type of bra) and an increased risk of breast cancer,” Komen writes. “There is no biological reason the two would be linked, and any observed relationship is likely due to other factors.” Komen also lists abortion, miscarriage, exposure to pesticides and chemicals, breast implants, cell phones, deoderants, and other examples as things that don't cause breast cancer despite claims that they do.

Indeed, the “biological reason” Grismaijer and Singer point out is lymph damage. But Dr. Ted Gansler, director of medical content for the American Cancer Society, told The New York Times that wearing a bra — which would only minimally affect lymph flow if at all — was not likely to be connected to breast cancer from lymph damage.

The study tossed around that either began or added fire to this question was a 1991 case-control study that discovered that premenopausal women who didn’t wear bras were less likely to develop breast cancer than those who did wear bras. However, the other factors that are often involved in determining breast cancer cause — such as weight — were not taken into account in this study. Likewise, the authors concluded that the fact that non-bra wearers were more likely to be lean could have played a role in their decreased risk. Some studies have shown that large breast size could be a risk factor in breast cancer. However, other studies have shown no association between breast size and increased risks.

Currently, the only thing that scientists can say with certainty is that certain gene mutations can significantly increase the risk for breast cancer. Environmental factors have been linked to breast cancer prevalence, as well as hormone levels, but they are still being researched preliminarily. If you want to take your bra off when you go to sleep, more power to you. But don't expect that it will significantly decrease your risk for breast cancer — at least not until further evidence appears.