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crystal deodorant potassium alum safe

Think “aluminium free” deodorant means that you’re avoiding all aluminium? You might need to think again, especially if you’re using crystal deodorants as a low tox alternative.

Like many of us trying to choose healthier options and switching to a natural deodorant, when I first I saw these crystal deodorants I thought they were the perfect way to avoid aluminium. 

At first glance, there seems to be a lot to like. Many of them have short, simple ingredients lists. The packaging promises things like “natural salt deodorant”, “aluminium free” and “mineral stick”. 

Others claim that they’re great for people with allergies, “safe for sensitive skin” and are completely free of harmful chemicals

It’s no wonder we think that a deodorant rock crystal sounds about as safe and natural as they come –  they’re mineral salts originating from mineral crystals. Some of these deodorants even come in crystal or stone-like form.

But is a mineral salt deodorant all it’s cracked up to be? 

Is crystal deodorant safe?

First of all, what is crystal deodorant made of? 

Let’s have a look at crystal deodorant ingredients. I found one called Crystal Mineral Deodorant Stick unscented.  It’s got just one ingredient: potassium alum (natural mineral salts).

Potassium Alum.

That’s right. And if you think that Potassium Alum sounds a bit like aluminium, you’d be right. Sometimes you’ll see this listed as crystallised alum, or just mineral salts. 

So to answer our question, does crystal deodorant contain aluminum – the answer is yes. Even though many crystal deodorants have “aluminium free” labels, the main ingredient in many crystal deodorants, potassium alum, contains a form of aluminium.

If you’re trying to avoid any form of aluminium in your skincare products, that knowledge might be enough for you to avoid deodorant crystals altogether.

What is potassium alum?

Potassium alum, or potassium aluminum sulfate, is a naturally occurring mineral salt. 

Crystal deodorants will often state that they’re aluminium free, but what they really mean is that they’re free of aluminium chlorohydrate, aluminium chlorohydroxide and aluminium zirconium.

One of the harmful effects of deodorant, especially traditional antiperspirants, is that they use aluminium to block sweat glands and prevent odour. So how does potassium alum deodorant work differently? Apparently it creates a temporary layer over the skin that inhibits the growth of odour-causing bacteria. 

Of course, now we need to ask the question: is potassium alum absorbed through the skin?

This ingredient is marketed as safe because it doesn’t penetrate the skin due to its molecular size. However, that’s not the end of the story. 



Natural Deodorant Cheat Sheet

Toxic Beauty: Deodorants


So is potassium alum safe in deodorant?

Even though potassium alum is considered to be safe because the size of the molecules are apparently too large to enter the skin, we may want to question that. Pharmaceutical companies are exploring the use of alum based powders as an alternative to injectable vaccines due to its properties helping other ingredients absorb into the skin and become active in the body.

In addition, wetted crystals are actually broken down into ions, the smallest possible form of aluminium, which is easily dissolved in water. And considering crystal deodorants in stone form ask that water be applied before use, and that the first and largest ingredient in any crystal deodorant spray is water, and that our bodies are largely made up of water, the theory that any aluminium in a potassium alum based deodorant won’t be absorbed through the skin struggles to stand up to these findings.

And while manufacturers say that ‘it’s understood’ that potassium alum isn’t absorbed into the skin, what they really mean is that there hasn’t been enough research done on this. We do know that using antiperspirants containing aluminium may significantly increase the aluminium absorbed by your body.

However, government bodies have reviewed potassium alum safety and agree that it’s low tox.

So is alum crystal deodorant safe? Potassium alum does contain aluminium, and it could very well be absorbed into the skin but the research shows that it’s of low concern.

Crystal deodorants aren't always just natural minerals

It seems as though a natural crystal deodorant stick is probably one of the safest versions of aluminium deodorants. 

BUT, potassium alum can also be synthetically produced, often using aluminium hydroxide (a white cosmetic opacifying agent) mixed with potassium or ammonium sulphate in sulphuric acid. And there’s that little ‘gotcha’ moment – knowing the ingredients are okay is not enough if they’ve been synthetically produced using the toxic chemicals you’re trying to avoid.

Liquid crystal deodorants are made by “dissolving a powdered crystalline double sulfate of aluminum (alum) in a saturated solution of water, or a combination of water and alcohol”. Often, synthetic fragrances and preservatives are added, which means you’re not using a natural product at all. 

What's the verdict?

So is potassium alum in deodorant safe? Since there’s no doubt that potassium alum contains aluminium, if your switch is in an effort to reduce the amount of aluminium build up in the body, you will want to look for something else for natural protection.

I’ve only talked about the naturally occurring crystal deodorant sticks here. There are lots of versions of crystal deodorants, including plenty that are “mineral enriched”. You’ll find roll on and spray versions, too. That means that potassium alum is just one of the ingredients. 

As always, you need to read the back of the pack carefully. Potassium alum might be okay, but you need to make sure that ALL the ingredients are good.  

Which are the best crystal deodorants to use? 

We get readers from all over the world, so I’ve split these out to help you find a good alum stone deodorant no matter where you are! As always, I’ve chosen the unscented versions to avoid the chemicals that are found in synthetic fragrances. 

Best Crystal Deodorant USA

Best crystal stick deodorant: CRYSTAL Unscented Mineral Deodorant Stick

Best crystal spray deodorant: CRYSTAL Body Deodorant Spray

Best roll on crystal deodorant: CRYSTAL Mineral Deodorant Roll On 

Best Crystal Deodorant UK

Best crystal stick deodorant: Salt of the Earth – Natural Deodorant Crystal Classic

Best crystal spray deodorant: Salt of the Earth – Refillable Natural Deodorant Spray 

Best roll on crystal deodorant: Salt of the Earth – Natural Deodorant Roll On

Best Crystal Deodorant Australia

Best crystal stick deodorant: Grant’s of Australia Natural Crystal Deodorant

Best crystal spray deodorant:

Best roll on crystal deodorant:

Decided to give crystal deodorants a miss? Here’s the best aluminium free natural deodorants.

Here’s our top picks for natural deodorants without the crystals.

Best Aluminum Free Deodorants USA

Each & Every Natural Aluminum-Free Deodorant – EWG Verified

Native Deodorant – hugely popular natural deodorant

Humble Brands Original Formula Aluminum-free Deodorant – all fragrances are from essential oils

Peach Not Plastic Deodorant Starter Kit – EWG verified and it’s refillable

Weleda Deodorant Spray, Citrus – one of my all time favourites, NaTrue certified and UEBT certified

Best Aluminium Free Deodorants UK

Fussy – Natural Refillable Deodorant – this brand does have some synthetic scents, but it’s easy to check which. 

The Natural Deodorant Co – plastic free packaging with scents from essential oils

Weleda Deodorant Spray – Citrus – one of my all time favourites, NaTrue certified and UEBT certified

Wild Deodorant – another refillable one (love the packaging!) with natural fragrances

Procoal Natural Deodorant Balm – plastic free with activated charcoal

Best Aluminium Free Deodorants Australia

No Pong – Original – All Natural Deodorant – plastic free, and one that I’ve used and loved

Sukin Natural Deodorant – reasonably priced and works well

Native Deodorant – cult favourite available in Australia

Woohoo Body – Tux – plastic free packaging, Australian made brand

Noosa Basics Roll On Lemon Myrtle – glass bottle, another Aussie made brand

Weleda Deodorant Spray – Citrus – my fave!

Check out our Safer Deodorants Cheat Sheet to find out what really is natural and safe!

Have you made the switch to a natural deodorant? What’s your fave?

Image source: Deposit Photos

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