Most deodorants contain a combination of aluminum-based compounds, synthetic fragrances, emollient oils, polyethylene glycol distearates and alcohol. Additionally, many deodorants contain talcum powder and preservatives, such as parabens or the chemical butylated hydroxytoluene, or BHT.
Aluminum-based compounds are the most common ingredient in deodorants and antiperspirants because they seal sweat ducts and temporarily prevent perspiration from getting on the skin. According to Dr. David Pariser, a professor of dermatology at Eastern Virginia Medical School, these compounds work best on dry skin and should be applied before bed rather than immediately after a shower or bath, notes Jeannette Moninger for WebMD. Despite wide-spread rumors linking aluminum compounds in deodorants to breast cancer and Alzheimer's disease, no scientific evidence of such links exists.
Emollient oils, such as mineral oil or sunflower oil, are used in many roll-on and stick deodorants because they help the product glide on smoothly and prevent it from flaking off when dry. Additionally, alcohol is used to dissolve aluminum compounds in some roll-ons, gels and sticks. Polyethylene glycol distearates are emulsifying agents used in many cosmetics and deodorants to make the products easier to wash off. Fragrance is included to mask odors.
Parabens, such as methylparaben and propylparaben, commonly were used in deodorants to slow the growth of bacteria. Manufacturers started using them less frequently after 2010 as consumers began advocating for preservative-free hygiene product alternatives. BHT, another preservative, is still used to slow the deterioration of ingredients after the product is opened and exposed to air.