
What is an alum stone and how do you use it?
Crystal deodorants can seem like a bit of a hoax. We, like many of you, were huge skeptics before we joined the alum stone club. Let us start by saying it’s not like using a crystal to attract love or abundance… Although we’re all for having a crystal collection! LOL. The alum stone is really just a block of salt. It prevents bacteria which in turn prevents odor. It’s that simple! In this blog we’ll dive into what an alum stone is and what it’s not, and share our top tips for how to use an alum stone.
You might have seen crystal deodorants before, in a plastic applicator just like regular roll-on deodorants. It's been around for a really long time, but a lot of people have never had success with it. Well, not only did we find an alum stone that is completely plastic-free, but we found the secret that‘s worked for over 700 people and counting! Don’t take our word for it, check out some of the reviews they’ve left. Read on to find out our secret for how to use a crystal deodorant and a step-by-step guide to using it as an aftershave or a facial toner as well.
What’s in an alum stone?
Alum stones are a mineral salt in crystal form, made of a single ingredient: potassium alum. This is not the same chemical compound as the aluminum which is found in most conventional deodorants. Potassium alum has antimicrobial properties (which is a big part of why they work), and it has been used since antiquity. Ancient Egyptians used it as a dye, as a mordant in textiles and for tanning. Beginning in medieval times, it was used in medicine as a styptic for minor wounds and cuts. It is still widely used in water treatment, medicine, cosmetics, and even in food (in baking soda and pickling). You can find it at pharmacies as a styptic pencil for first aid, at barbershops as an aftershave, and in cosmetics as an astringent. It has been used as a deodorant for a long time as well, and ours has a smooth rounded shape that's easy to hold and easy to apply.
How does it work?
Unlike other deodorants, alum stones don't cover up body odor with fragrances or perfumes. To use it, you wet the top and apply it to your skin, leaving a thin layer of salt. The salt works to stop bacteria from forming, so you don’t develop any unpleasant scent. As a mineral salt, it is naturally antimicrobial and antiseptic, which allows it to fight odor-producing bacteria. Think of it as a layer of mineral salt that sits on the surface of your skin and keeps body odor at bay. It leaves no scent on the skin and it’s made with a single ingredient which is great for sensitive skin. When you apply to clean skin, you’ll be completely odorless and feel fresh for hours. Plus, it's a clear salt, so there's no white streaks!
You can also use the alum stone as an aftershave - it tones and firms the skin and stops any bleeding from nicks or cuts. It’s a styptic, meaning it tightens tissue and helps blood to clot, so you can use it on your face, legs, or anywhere else you have a small cut. It's popular for use after shaving, but we also like to keep one under the sink or in our first aid kit to treat other minor cuts and abrasions.
It’s astringent and drying, so you can also use the alum stone as a facial toner to treat blemishes, keep acne away, and draw out oils and

How do you use an alum stone?
You can use an alum stone as a deodorant, aftershave or facial toner. Be sure to let it dry between uses and store it somewhere safe from falls - a soap tray or small dish works perfectly for this.
Here's our best tips and tricks for how to use the alum stone.
How to use the alum stone as deodorant:
To apply as deodorant, simply wet the top of the alum stone and rub it onto your skin as you would any deodorant. Smooth it onto your underarm area until most of the water is absorbed, to create an invisible salt layer. Let your skin dry for a couple of seconds before putting on clothes.
The secret to making the crystal deodorant work is to make sure you're applying to clean skin! Before you apply, make sure you've either showered, shaved, or simply cleansed the underarm area with a little soap and/or hot water. Any of these will work, but the idea is to make sure you have no odor to begin with. The alum stone won't hide odor that's already there, but it can prevent any from appearing on clean skin! If you find it easier, you can also apply your alum stone the night before and in our experience it lasts through into the next day.
You may experience a detox period if you're switching from traditional deodorant. Give your body a few weeks to adjust to the difference and you should see it start to work. If you’re having trouble, try this pit mask recipe!
A lot of our customers say it makes their skin feel super silky and soft after use. An added benefit of its toning properties!
How to use the alum stone as an aftershave:
Many people like to use the alum stone on their face after a shave because of its toning and astringent properties. It is also antiseptic, meaning it can help soothe any razor bumps, razor burn or redness. To use your alum stone as an aftershave, wet the top of the stone and apply to your skin directly after you shave. Rub the stone around until most of the moisture is absorbed.
If you want to apply an aftershave balm or facial moisturizer as well, splash some water on your face after using the alum stone and then follow it with your moisturizer or aftershave.
To use it to stop bleeding, wet the top and rub over the cut until it dries, and it should stop bleeding almost right away. It can sting a bit since it's a salt, but that means it's working.
You can also use this after a bikini wax or sugar wax because it calms the skin, protects against infection and should soothe any inflammation or bumps that can occur. It can have a light stinging because it is a salt, so try this with care.
How to use the alum stone as a facial toner:
The alum stone mineral salt crystal can be a great spot treatment for oily complexions and acne prone skin. It's an astringent, which means you can use it to dry out problem areas or just tone and tighten your skin. Simply wet the top and apply to affected areas.
You can do this at night, or in the morning but do note that it can be drying on some skin types. Be careful to not over-use this treatment as it can dry out your skin or throw your natural oils out of balance. A couple of times a week should be fine.
Is it safe?
Yes, alum stones are a safe and effective natural deodorant. They're actually made of potassium alum which is different than the aluminum found in conventional deodorants, and they don't possess the same health risks. Regular antiperspirant deodorants usually contain either Aluminum Chloride, Chlorohydrate or Zirconium, all of which have known health concerns.The aluminum found in conventional deodorants is thought to be an endocrine disruptor which causes all kinds of hormonal problems and health risks. Potassium alum on the other hand is a mineral salt with a large molecular structure that sits on the surface of your skin rather than being absorbed. It is not a heavy metal and it doesn't disrupt your skin's microbiome. Rather, it is a gentle and effective natural mineral salt that is ethically mined in France.
We loved this Mind Body Green article on how crystal deodorants work and what dermatologists had to say. It links to some helpful research articles, too. The Environmental Working Group (EWG) deems it safe as well, which gives us peace of mind.
The beauty of a crystal deodorant is that it's also free from all the additives and ingredients that usually cause irritation, like parabens, phthalates, artificial fragrances and dyes. It is safe for sensitive skin and free of toxins.
As with any topical product, discontinue use if skin irritation occurs and consult your doctor.
How long does it last?
As a deodorant, each stone can last you for five years! I’ve been using mine consistently for about two years now and it’s smoother on top and about half an inch lower in height. You can see the difference when you set it next to a new one but it’s still huge! I’m going to guess it will last me a little over five years but it does depend on how often you use it and where. As an aftershave, if you used it daily on your face I’d say about the same, 4-5 years. That being said, Bea Johnson (mother of the zero waste movement) said hers lasted her about 10, so I guess it’s about how you use it!
You can use the alum stone until it’s too small to hold. After that it’s basically a small rock so you won’t want to try to compost it, but you can keep it as decorative or you can sand it down into a powder, add the powder to water and turn it into a deodorant spray!
The magic of crystal deodorant
The history of alum stones is fascinating, and there's so many ways to use them. As a crystal deodorant, they leave your skin smelling fresh and clean, and they contain no perfumes, dye or aluminum. They look stunning on your counter and one stone can last you for about five years. They’re so good for the skin to fight blemishes, tone the skin and treat any cuts from shaving. We’ve had over forty rave reviews and counting. Try it for yourself and let us know what you think!
Comments
Genevieve Fisher said:
Hi Tasha – Yes absolutely. It works on hairy armpits as long as you get enough of the saltwater onto the skin and let it dry. And it’s great for acne, both healing and preventing. Hope that helps! :)
March 23, 2023
Genevieve Fisher said:
Hi Shan! You could, but it might disrupt the salt layer. I imagine it would only work as well as the other deodorant works. You don’t necessarily want to layer it with anything but if you love the scent of the deodorant, maybe you could use it as a cream perfume!
March 23, 2023
Shan said:
Can we use the rock and then apply deodorant on top?
October 10, 2022
Tasha said:
I have a question? maybe two.. Can a fellow with hairy armpits use this stond? And, maybe I missed it, but would it help with acne in that sensitive area?
December 04, 2020