First things first: The term “48-hour deodorant” should not be taken too literally. Even the manufacturers assume that you wash yourself once a day. Rather, behind the name is the security promise that the deodorant is guaranteed not to let you down all day. You should also know that deodorant is usually only used as a colloquial umbrella term for deodorant and antiperspirant. Two types of product that clearly differ in their mode of action.
A deodorant targets skin bacteria. With the help of antibacterial agents such as triclosan or silver citrate, they fight the bacteria that give sweat its unpleasant odor, or cover it with fragrances. If you want to nip the development of sweat in the bud, you should use an antiperspirant. The contained aluminum salts constrict the sweat glands and thus inhibit sweat production. For a long time, aluminum salts were criticized because the active ingredient accumulates in the body and – so the assumption – can promote breast cancer and dementia, for example. But according to studies from 2019, the Federal Institute for Risk Assessment has given the all-clear here: absorption through the skin is significantly lower than assumed. A health risk is currently unlikely for both hairy and shaved armpits.
What, in addition to deodorants, also protects against unpleasant underarm sweat: You should use soap in the shower, because water alone is less effective in eliminating odors and bacteria. If the armpits are shaved, there is in principle less sweat, and bacteria are also less likely to multiply in a hair-free environment.