We had an interesting research project on deodorants and in specific the relatively new crystal deodorants that originated in Thailand.
We learned that our western cleanliness lends to the need of a deodorant. When we wash with alkaline soaps this increases the pH of our armpits and that is a better environment for the bacteria that than the slightly acidic nature of an unwashed arm pit. The bacteria feed on sweat from the apocrine glands and dead skin. The bacterial waste product is trans-3-Methyl-2-hexenoic acid and is the primary cause of body odor.
There are two ways to reduce the smell of an armpit and that is through reducing the amount of sweat and by deodorizing the smells.
Antiperspirants work by clogging the armpits pores. Aluminum chlorohydrate and aluminum zirconium tetrachlorohydrate gly – as well as other aluminum-based compounds, react with sweat to form a gel plug in the sweat gland duct. The aluminum salts also interact with the keratin fibrils in the sweat ducts and form a physical plug that prevents sweat from reaching the skin’s surface. The astringent properties of Aluminum salts cause the pores to contract. It is by shrinking and blocking the pores that an antiperspirant works.
Deodorants typically work by both acidifying the under arm as well as by the use of anti bacterial compounds such as alcohol and triclosan to kill the bacteria.
The new alternative to these more modern formulations is ammonium alum, which is a common type of alum sold in crystal form and often referred to as a deodorant crystal. It has been used as a deodorant throughout history in Thailand and other countries. One might also see potassium alum as well. These work as a very strong anti bacterial. While not preventing perspiration they create an environment in the nice warm armpit such that it is unfavorable to bacteria.
We also discovered that many of the commercial deodorants and antiperspirants have some sneaky ingredients. Several contained substances that would, over a period of 12 hours or so – provide a growing medium for bacteria. They also contained some compounds that change their scent over time under heat and moisture. Thus, many deodorants contained elements of what we can call re-odorants. When our team learned about deodorants two members had an “ah ha” moment. Both wondered why they smelled worse in the morning than after an extended campout when they used no deodorant? Re-odorants may explain their experience.
So what has been the experience of our test crew with crystal deodorants? For the most part the crystal deodorant was 100% effective for about 20 hours. Also for those with sensitive skin, less reactions to these types of deodorants as opposed to those major formulated brands.