Zinc Oxide and Magnesium hydroxide combo in deodorant

Hi there, I’m formulating a deodorant replacing baking soda which can irritate sensitive skin with the above mentioned chemicals. In my research I found that some people respond better to zinc oxide than magnesium hydroxide and vice versa when it comes to odor protection. I haven’t come across many recipes that use both in their formulations and was wondering if anyone can tell me if there is a potential bad reaction between zinc oxide and magnesium hydroxide if I were To use them in combination with each other?

Comments

  • chemicalmattchemicalmatt Member, Professional Chemist
    Compatibility should not be a problem, especially considering both have little solubility to begin with. You are creating a suspension not a solution. 
  • raiyanaraiyana Member
    edited December 2019
    i've seen natural deodorants with zinc oxide and/or magnesium hydroxide before and claim to be more gentle compared to baking-soda deodorants. baking soda due to its high pH is like an evil ingredient in deodorants. Thats what i see some brands claim anyway. But magnesium hydroxide solution has a high pH too.
    For a person who has been using own-made deodorants for about a year now (a combination of MCT oil, beeswax, arrowroot powder, magnesium hydroxide and sometimes Diatomaceous Earth or zinc oxide), i have to say these natural deodorants can really work to combat body odour (but you will still sweat, not like antiperspirants).
    BUT, they also increase the chance of having pimples under your pits, yeast infections, rashes... I started getting these tiny pimples under my left pit after months of using natural deodorant which i thought was totally working. i stopped using and no pimple after that. 
    The pits arent well ventilated like the face. It's a dark, sweaty place, a nice place for microbes to live happily. homemade deodorants contain lots of food for microbes, hence the pimples.
    Now i'm using natural deodorant only when I'm going out because it works. But i hate the pimples after prolonged use. Maybe it's just me. My husband uses the same deodorant and he never got any pimples. He actually likes this natural deodorant that I make and thinks it's performing better than antiperspirant. (we dont use anti-perspirants cuz I like making and testing my own personal care stuff, some people like DIY. hehe)
    One more thing, these natural deodorants like to include a nice blend of essential oils like peppermint that can be sensitizing to some people. I've tried making mine with menthol before. Just a very tiny amount of menthol for that cooling sensation. I had the biggest rash a few hours after applying that deodorant for the first time. My husband didnt. I never had issue with menthol before, but somehow when i used it under my pits, I got a rash.
    Sharing this because these are the things you need to consider when  formulating your natural deodorant for sensitive skin. You can put whatever claims. but when a customer complaints about a rash = big problem.
    Maybe you can start with a standard nappy rash formula (with zinc oxide) and add deodorizing ingredient.... food in the kitchen like cornstarch isnt a good idea (speaking from experience, pimples...) and some people can have yeast infection! Thats why it isnt a good idea to use cornstarch for nappy rash powder - same concept for underarm products. Sorry for the long post! 
  • Compatibility should not be a problem, especially considering both have little solubility to begin with. You are creating a suspension not a solution. 
    Thank you so much! 
  • Thanks for your information on ingredients in natural deodorants. Beeswax and arrowroot would give you pimples. Maybe you should use some lighter materials if you wanted to reformulate and still make your own. 
    Dr. Catherine Pratt
    (B.Sc with HONS I , Ph.D Analytical/Organic Chem and Microbiology), Cosmetic Chemistry IPCS)
  • Suzita8Suzita8 Member
    @Bdegro ; - hi there;
    I have been making deodorant for 3 years now, and as @raiyana mentioned, some in my family also got the "pimples" (very painful), but we determined after trial and error that it was due to the baking soda. So i started replacing it with Magnesium Hydroxide, and also using just .5% of zinc oxide and it's been great! Mind you, i'm still finding it's not as effective for big stinky people (like my youngest daughter, haha) as the baking soda one, yet for others (like my husband) it works great... 
    I was wondering if you would mind sharing how it's been going for you? Did you end up making a new deodorant? Thanks, cheers,
  • kajo80kajo80 Member
    I heard zinc hydroxide to be better compatibility with magnesium hydroxide. Does anyone know where to purchase zinc hydroxide?
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