Experts warn against certain ingredients present in most deodorants and antiperspirants.
While underarm products are not being digested, medical experts said that cosmetic ingredients being applied on the skin may be worse.
"When you eat something, it's broken down by your liver and digestive system," Dr. Heather Patisaul, associate professor of biology at North Carolina University, told Time.
"But when you put something on your skin, there are times when it can enter your bloodstream without being metabolized," Patisaul added.
According to Patisaul, there are such things as "endocrine disruptors" that could mess with the function of the body's reproductive and developmental hormones. Some chemical substances may enter the bloodstream when applied on the skin, she said. But according to blood tests, many of the substances present in deodorants can actually enter through the epidermis and into the body.
Another research conducted by Dr. Philp Harvey, edictor-in-chief of the Journal of Applied Toxicology, showed that compounds used in deodorants are being absorbed and stored in fat cells clustered in the underarm area.
In a more alarming study, author Philippa Darbre, an oncologist at the University of Reading in the UK, found that the aluminum content of most deodorants and antiperspirants may cause "gene instability" in the breast tissue that may lead to breast cancer risks.
However, Dr. Ted S. Gansler of the American Cancer Society said that many of these studies are "flawed," that even though some had detected chemicals from underarm products in breast tissue, they did not prove that these chemicals had any effect on breast cancer risk.
Aside from aluminum, Time reports that these other ingredients present in most underarm products are raising concerns among health experts.
1. Parabens - used as preservatives in deodorants and other cosmetic and personal care products.
2. Triclosan - added by cosmetic manufacturers to their products to prevent bacterial contamination.
3. Phthalates - help deodorant and other cosmetics stick to the skin.
4. Fragrance - scents added to the product which are said to cause some allergies.