Wearing a bra restricts blood and lymph flow. In comparing breasts and testicles, according to Dr. Elizabeth Vaughan, owner of Integrative Medicine, in Greensboro, North Carolina, a man’s testicles are warmer when held close to the body, which reduces testosterone and sperm production. Fertility clinics will tell a male partner to get out of tight-fitting underwear to allow the testicles to be cooler and move freely. This increases sperm production and fertility. 

Breasts, like testicles, are meant to be cooler, as seen in thermography. Adequate blood flow in the breasts brings in nutrients and distributes hormones that are made in the breasts. Wearing a tight bra, especially with underwire, compresses the tissues and reduces blood and lymph flow. This allows the buildup of toxins and estrogen in breast tissue that can lead to fibrocystic breast and breast cancer.

Studies from around the world have shown that women who wear bras have a higher rate of breast abnormalities. A study from Scotland in 2014 reported breast cancer may be caused by “cleavage-enhancing bras due to the constricting effect of built-in-wiring on breast tissue and the lymphatic system.” A study from Brazil in 2016 showed the more hours a woman wears a bra and the tighter the bra, the greater the incidence of breast cancer in both pre- and post-menopausal women.

This is not new information. The first study to recognize the association between bra usage and the risk of cancer was published in 1991 by Harvard researchers. Sydney Ross Singer and his wife published the book, Dressed to Kill, after finding women in Fiji, and later in America, who wore a bra longer were at a greater risk of developing breast cancer.

Once going bra-free, most women notice improvement in breast lumps and breast tenderness. Some women notice a transient period of increased breast tenderness or achiness as toxins are moving out of breast cells and into the lymphatic system. This generally does not last more than three weeks even in large breasted women. When there is discomfort, a simple breast self-massage to move the toxins out is very helpful.