A lot of women don’t understand why radiologists ask them not to wear deodorant when they come in for a mammogram. Most deodorants and antiperspirants contain aluminum, which blocks sweat ducts and prevents you from perspiring. The amount of aluminum in the average bar of deodorant is small, however, even a small amount is enough to interfere with a mammogram.

The aluminum particles in deodorant look like tiny white dots on mammogram, mimicking the appearance of calcifications on a mammogram. Calcifications can be an early sign of breast cancer. If there are any aluminum particles in the picture, it becomes difficult to distinguish deodorant aluminum from calcifications. This is why doctors ask patients not to wear deodorant on the day of her mammogram. Without deodorant, they can be certain they’ll get a clean image they can use to evaluate the patient’s health. For patients worried about odor, consider bringing deodorant with you and applying it after the exam.