Patients often ask me about things they’re exposed to every day that might increase cancer risk. Sometimes, the answers are straightforward: No, microwave ovens aren’t linked to cancer; yes, smoking is. Far more often, though, the answer is cloudier. In many cases, it’s hard for science to find a firm link between things we suspect are making us sick and a specific disease. That’s because so many factors are involved.
Lingering questions about real health concerns lead to the troubling rumors. One particularly persistent one links aluminum in antiperspirant to breast cancer. Patients often ask me if there’s any truth to it. While most of us use antiperspirant every day, we’d probably learn to live without it if it were dangerous.
Based on what we know today, the answer is stuck at “probably not” or “maybe.” We want to help you make the best choices, but research on the topic isn’t conclusive yet. The best thing to do is inform yourself about what’s known so far and make the choice that’s best for you.
Antiperspirants contain aluminum-based salts, an active ingredient that blocks sweat. Some people believe that this aluminum is absorbed into the lymph nodes under the arm, builds up over time, and damages cells in ways that lead to cancer.
The belief is based on these concerns:
- Researchers have found traces of aluminum in breast fat, breast tissues, and breast fluids, and in breast milk.
- Most breast cancers develop in the upper outer area of the breast that’s closest to the lymph nodes exposed to antiperspirants.
- Many women apply antiperspirant after they shave their armpits. Shaving can cause small cuts and irritation that make it easier for the body to absorb aluminum. This is why antiperspirant labels warn people not to use it on broken skin and to stop use if rash or irritation occurs.
Some rumors also suggest that the reason men have a lower risk for breast cancer is because their underarm hair blocks antiperspirants, so they absorb much less of the product. But science shows clearly that men are less likely to develop breast cancer because they have less breast tissue and their bodies’ natural male hormones usually don’t stimulate the growth of breast cells. Men’s bodies have very little estrogen, one of the hormones that increases breast cancer risk in women.
A handful of studies have looked at the possible link between antiperspirants and breast cancer. The results have been mixed or inconclusive:
- A U.S. study published in 2002 compared the effects of antiperspirant and deodorant use in more than 1,500 women, half of whom had been diagnosed with breast cancer. The researchers found no evidence to support the idea that antiperspirant use increases the risk of breast cancer, including among women who used it after shaving their underarms.
- A U.S. study published in 2003 surveyed more than 400 women diagnosed with breast cancer. Women who used antiperspirant or deodorant frequently and who shaved their underarms were diagnosed at an earlier age. The researchers concluded that underarm shaving and using antiperspirant or deodorant might play a role in breast cancer, but it wasn’t clear which ingredient(s) in the underarm products may be involved.
Reviews of research generally conclude that the evidence doesn’t show a link between antiperspirants and breast cancer. But many doctors also feel that the studies are too limited and more research is needed.
This is what we know so far:
- Most of our exposure to aluminum happens through eating and drinking. The lightweight metal occurs naturally in very small amounts in much of the water we drink and in some of the food we eat. It’s sometimes added to processed foods to improve texture, including some cheeses, pickles, and breads. It’s also in some medications, including buffered aspirin and antacids, vaccines, and in personal care products, including some nail polish, eye shadow, and lip products. Many pots and pans are made of aluminum and small amounts of the metal can leach into food during cooking. The same goes for food and beverages stored in aluminum cans or foil.
- There’s very little research on how much aluminum is absorbed through the skin from antiperspirants. The amount from any one application appears to be extremely tiny. But damaged skin — either from shaving or a rash — does seem to absorb more aluminum than healthy skin.
- It’s true that researchers have found traces of aluminum in breast tissues and fluids. They can’t tell, though, if the aluminum comes from antiperspirant use or from other sources. Scientists also have found traces of aluminum in blood, as well as bone, muscle, brain, and other tissues.
- In general, the body holds onto very little of the aluminum that it takes in through normal daily exposure. It doesn’t need it for any functions, and most leaves the body when you go to the bathroom.
- It’s true that there’s a greater incidence of breast cancer in the upper outer area closest to where antiperspirants are applied. Most scientists don’t think this is because of antiperspirants, though. Instead, it’s because there’s more breast tissue in this area. The number of breast cancers in this area is proportional to the amount of breast tissue in the area.
- Whether aluminum from antiperspirants or other sources plays a role in cancer remains unclear. One study of women diagnosed with breast cancer documented higher levels of aluminum in the area that’s close to the where antiperspirants are applied. Other studies have found more aluminum in breast fluid and tissue samples from women with breast cancer compared to samples from healthy women. But another study found no difference in the amount of aluminum in breast cancer tissue samples compared to normal breast tissue. And just because a chemical is found in the breast area doesn’t necessarily mean that it’s causing trouble.
What you can do
Even if there’s no link between antiperspirants and breast cancer, it could still be wise to reduce your exposure to aluminum for other reasons. The nervous system, including the brain and spinal cord, is considered the most sensitive target of aluminum. Some research suggests that aluminum might be linked to Alzheimer’s disease. Most experts don’t think that everyday sources of aluminum increase the risk of Alzheimer’s. But the issue is controversial.
Aluminum is so common in our environment that it’s impossible to avoid all exposure to it. But if something may pose a health hazard, it’s smart be cautious. Here are some straightforward things you can do to limit your exposure:
- Don’t apply antiperspirant immediately after shaving. Try switching up your routine: shower at night and shave your armpits. Then apply antiperspirant in the morning, after any skin irritation has eased.
- Use antiperspirant with a lower concentration of aluminum. You may not notice the difference unless you’re someone who sweats a lot. Check the label: aluminum as an active ingredient ranges from around 15% to 25%. The higher the percentage, the more aluminum the product contains (and the greater its ability to keep you dry).
- Switch to deodorant. Deodorants block body odor but not underarm wetness because there’s no aluminum. Check the label to be sure — if aluminum is in the product, it must be listed clearly on the label as an active ingredient. It might take some experimenting to find a deodorant that truly blocks odors. To find ones that are free of parabens and synthetic fragrances, check the Environmental Working Group (EWG) Skin Deep Cosmetics Database.
- Cook with non-aluminum pans, such as stainless steel or cast iron. Or use anodized aluminum pans, which have been treated so they don’t leach aluminum during cooking.
- Some foods may contain aluminum-based food additives. Processed cheeses may contain an aluminum-based emulsifying agent and pickles may contain alum, which improves crispness. Store-bought bakery goods may use baking powder that contains aluminum. Check food labels and avoid as many foods as you can that contain alum, alumino, aluminate, or aluminum. When you’re cooking, use aluminum-free baking powder.
- Avoid aluminum-containing antacids to treat heartburn and indigestion. Try drinking a cup of peppermint tea or chewing gum instead.
- Use shampoos, soaps, lotions, and cosmetics that don’t contain aluminum. If you’re unsure whether they’re aluminum-free, check the EWG database.
- Buy fewer canned foods and drinks. Try jarred tomato sauces and frozen vegetables, which often taste fresher than canned anyway.
Some of these changes are easy. I already avoid canned foods because the inside of most cans is coated with bisphenol A (BPA). My pots and pans are cast iron or stainless steel. (For more information on BPA, read my Think Pink, Live Green column on avoiding BPA. But switching to deodorants is easier said than done. It’s hard to give up dry armpits! Even if they don’t smell, sweat circles on your shirt aren’t very attractive. Do you have recommendations for deodorants that really stop odor, or any other advice for people who want to stop using antiperspirants? I’d appreciate hearing your recommendations and advice!