People love the word “natural.” You’ll find this word on food, beverages, dietary supplements and cosmetics. People have become justifiably concerned about pesticides, fungicides, plasticizers, endocrine disruptors, preservatives and lots of hard-to-pronounce chemicals. Aluminum has also come under scrutiny over the last few decades. It is found in all antiperspirants. Many people would prefer to avoid this mineral, but not all natural deodorants are free of aluminum, as this reader discovered.

Natural Deodorants Are Not Always Aluminum-Free!

Q. I’ve always read labels carefully and avoided antiperspirants with aluminum. However, I thought that natural crystal deodorants containing potassium alum would be safe. After all, I’ve used alum for making pickles.

You have written that alum is actually aluminum. Now I feel terrible that I have not only used crystal deodorant myself, but I have also given it as gifts to my entire family. I wonder how many other people have been fooled.

A. Alum is an aluminum “salt.” One of the most common forms is aluminum potassium sulfate. It is used in water treatment plants to help precipitate floating particles so the water looks clear.

Alum is also used in pickling. Pharmacies sell styptic pencils that contain alum. It can stop the bleeding from a shaving cut. Natural crystal “rock” deodorants often list alum or potassium alum as the primary ingredient. Many people don’t realize that alum contains aluminum.

Antiperspirants MUST Contain Aluminum!

Antiperspirants also contain aluminum salts such as aluminum chlorohydrate. In fact, the FDA requires aluminum salts in all antiperspirants. That’s because such compounds cause swelling of the pores in underarm skin. As a result, the sweat glands are blocked and sweat can’t escape as easily.

Although the FDA considers aluminum salts safe, some scientists disagree. They worry that aluminum salts might act to change the way that hormones act in the body, including in breast tissue (Journal of Molecular Biochemistry, 2018).

The authors of this article introduce their research this way:

“Aluminum [Al] is the most abundant metal and the third most widely used. Humans are exposed to aluminum compounds through diet, antacids, vaccines, and various house hold products. Moreover, application of Al-based antiperspirant to the underarm provides a high and continuous exposure to aluminum of an area located to the near proximity to the human breast…accumulating evidence indicate that the aluminum ion (Al+3) is toxic. Abnormally high levels of aluminum are related to pathological conditions such as dialysis dementia, iron-adequate microcytic anemia, osteomalacia, neurodegenerative diseases, and breast cancer.”

These researcher reported:

“To conclude, our results show that aluminum salts induce a remarkable increase in estrogen receptor protein level possibly via interference with estrogen receptor gene expression or estrogen receptor protein stability. This effect may have consequences in breast physiology, affecting estrogen receptor mediated gene expression via direct or indirect estrogen receptor DNA binding…

“Our findings do not provide conclusive evidence that aluminum is a breast carcinogen. However, the daily exposure to aluminum in connection with its possible role as an endocrine disruptor raises concerns about the safety of its use.”

Unanswered Questions About Aluminum:

How much aluminum is absorbed from aluminum antiperspirants or natural deodorants containing alum? You will find some current research about aluminum absorption through underarms in this article

We need far better research about absorption. Last spring a study sponsored by the FDA discovered that ingredients in sunscreens were absorbed into the body. While it applies to completely different compounds, that finding came as a great surprise to most consumers. 

Are some people more susceptible to aluminum salts than others? This too remains a mystery. Some people tell us that aluminum antiperspirants cause them skin irritation. Others seem immune to this reaction.

Is aluminum a neurotoxin? The answer is yes, but does enough get into the brain to cause problems? This remains controversial.

What Else Can You Do?

We admit to a conflict of interest. Several years ago we developed an aluminum-free deodorant with magnesium hydroxide (milk of magnesia or MoM) as its active ingredient. One reader wondered about its safety too:

Terry writes:

“I do wonder about alternatives (such as milk of magnesia). If there are questions about the safety of aluminum, what about the safety of magnesium? Can one metal be substituted for the other without substituting a similar harm?”

Here is my answer to Terry:

There is a huge difference between aluminum and magnesium. Your body does not need aluminum to function. This mineral provides no biological function.

You could not survive without magnesium. It is absolutely essential for your body and many people are low in this electrolyte.

Here is what Medline Plus (from the U.S. National Library of Medicine) has to say about magnesium

“Magnesium is needed for more than 300 biochemical reactions in the body. It helps to maintain normal nerve and muscle function, supports a healthy immune system, keeps the heartbeat steady, and helps bones remain strong. It also helps adjust blood glucose levels. It aids in the production of energy and protein.”

Should you wish to learn more about magnesium-based deodorants, here is a link to several different options.

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