Back when chain emails were a thing, there was a pretty scary one circulating that claimed antiperspirant was a leading cause of breast cancer. By preventing sweating and thereby affecting your body’s ability to expel toxic substances, toxins accumulate in the nearby lymph nodes, the email said, and most cases of breast cancer occur in the upper quadrant of the breast near the armpit. The conclusion: Scent-masking deodorant is the safer choice.
While fearmongering emails have fallen out of favor, misinformation still abounds on the internet, including rumors that an active ingredient in antiperspirant can lead to Alzheimer’s disease. We looked into it: Is antiperspirant bad for you?
First, here's a refresher on how the stuff actually works. Deodorant fights odor by killing bacteria with alcohol, while antiperspirant does that and stops up your sweat glands temporarily with an aluminum compound.
Bacteria thrive in the alkaline environment of soap-washed pits.
Sweat ducts release sweat, which is water and salt.
Bacteria on your skin breaks down sweat into smelly acids.
Alcohol kills bacteria, while triclosan inhibits future growth.
Fewer bacteria means less odor. Fragrance helps, too.
The aluminum compound reacts with the salt in sweat to form a gel that temporarily blocks the ducts.
Aluminum also acts like an astringent, contracting the pores.
Alcohol kills bacteria; fragrance smells nice.
Antiperspirant doesn’t prevent you from sweating altogether — it reduces sweat by 20 to 30 percent depending on the strength — and even if our bodies absorb a very small amount of aluminum from antiperspirants, there’s no scientific evidence that it increases breast-cancer risk, says Harold J. Burstein, M.D., Ph.D., a senior physician of breast oncology at Dana-Farber Cancer Institute and associate professor of medicine at Harvard Medical School.
The proximity of the underarm to the area of the breast where most cancers arise is purely coincidental, too. “The incidence of breast cancer in the different parts of the breast — lower, upper that sort of thing — is directly proportional to how much ductal breast tissue there is in those quadrants,” says Dr. Burstein, who chairs the American Society of Clinical Oncology's guidelines on endocrine therapy for breast cancer. “There is a so-called ‘tail’ of the breast, which reaches back into the armpit, and women who’ve nursed know that.” Lymph nodes operate separately from sweat ducts, which are located in the skin, and you don’t “sweat out” toxins anyway; they’re cleared by your kidneys and liver.
Yet the antiperspirant myth persists. Dr. Burstein says people may try to rationalize a cause for a disease that still isn’t well understood. “A small number of women have hereditary predisposition for breast cancer but that only accounts for a small minority of breast-cancer cases,” he says. “For any given woman, we almost never know why she got breast cancer and I think that mystery prompts people to imagine that something else did it.”
If you do have a strong family history of breast or ovarian cancer (they’re sometimes genetically linked), it’s a good idea to discuss it with your medical team, who may recommend earlier or more frequent preventive screenings or even genetic testing, Dr. Burstein says. All women should have a “general awareness” of what their breasts look and feel like and get any changes evaluated promptly. As for your pits? “People should use antiperspirant as they wish without any concern whatsoever over breast health,” Dr. Burstein says.
What about Alzheimer’s? Researchers in the '70s found that rabbits exposed to aluminum developed nerve-cell damage in their brains, which was thought to be a precursor to the disease. Then in the '80s, researchers found high levels of aluminum in the brains of people with Alzheimer’s. Both prompted fears about everyday exposure in everything from pots to soda cans and antacids to, yes, antiperspirant. Studies since then have failed to prove a link between aluminum exposure and the progressive form of dementia. Experts note that the brains of Alzheimer’s patients shrink, which could explain the relatively high concentration of the metal compared to normal brains. Scientists doubt that aluminum plays any role in the brain disease.