Deodorant alone does not cause stains on clothing ? antiperspirants do. If the deodorant is also an antiperspirant, then stains may be left on clothing. The stains are caused by the aluminum-based compounds found in antiperspirants; when these active ingredients mix with sweat, stains are formed.
To reduce staining, only apply a single layer of antiperspirant, and let it dry fully before dressing. Applying antiperspirant at night before bed allows ample time for it to dry. To remove fresh stains, soak clothes in cold water with ammonia to neutralize the acidic antiperspirant.
Aluminum, which is found in antiperspirants, has been associated with Alzheimer's disease and breast cancer; however, scientific studies suggest little risk of absorbing aluminum by wearing antiperspirants.