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What’s In Your Armpits: Magnesium or Aluminum?

We're pitting magnesium against aluminum for your armpit health. Which is safer, magnesium or aluminum? Should you care what's in your pits?

Most people rarely read labels. Do you have any idea what’s in your toothpaste? What about your antiperspirant or deodorant? Be honest, now. Have you ever checked your antiperspirant label? Does it contain magnesium or aluminum? We’ll bet you a month’s salary that your antiperspirant contains aluminum!

Do NOT take that bet! You’d lose! That’s because no underarm product can claim to be an antiperspirant unless it contains aluminum. That’s an absolute FDA rule. There are no exceptions.

Can You Pronounce These Chemicals?

If you do check out your antiperspirant, you will discover tongue-twisting ingredients. Some contain Aluminum Zirconium Trichlorohydrex GLY. Others have Aluminum Zirconium Octachlorohydrex GLY. Then there are the relatively pronounceable aluminum chloride and aluminum chlorohydrate ingredients. If you see aluminum on the antiperspirant label, you know there is aluminum in your arm pit.

What’s the Big Deal?

So what? Presumably the FDA is looking out for us, right? In the case of aluminum, we’re not so sure.

Most people assume that the skin is a great barrier. We smear all sorts of things on our bodies, from sunscreen and moisturizer to soap and shampoo. For decades triclosan was widely distributed in soaps, body washes, mouthwash, toothpaste and deodorants. It is a preservative and antiseptic. Then the FDA effectively banned triclosan from soap. This antimicrobial agent is absorbed into the body and has hormone disrupting activity.

A couple of years ago the independent testing laboratory Valisure discovered benzene in some hand sanitizers, sunscreens, antiperspirant body sprays, dry hair conditioners and topical acne products. Benzene is considered a carcinogen. Exposure to this chemical has been linked to leukemia and cancers of blood cells.

As a result of these discoveries, many companies announced recalls. For example, Procter and Gamble (P&G) pulled a number of familiar brand name products off shelves. And the FDA notified consumers which hand sanitizers and antiperspirant aerosols contained benzene.

We conclude that the agency was concerned enough about consumers breathing or absorbing a carcinogen into the body that it issued announcements about the problem. So on the one hand, the FDA acknowledges that people may absorb unwanted chemicals through the skin. On the other, the agency insists that aluminum must be included in all antiperspirants.

Is Aluminum Toxic?

If you go to the National Library of Medicine’s website: PubMed and put aluminum toxicity into your search box, you will be astonished at how many articles come up.  At the time of this writing there were over 9,000 citations with with those key words.

Let’s narrow the search to aluminum and Alzheimer’s disease: That’s a more manageable number. There are over 1,500 citations at this link.

Aluminum and Alzheimer’s?

Most health professionals have assumed that the old “aluminum and Alzheimer’s” story disappeared without a trace long ago. Au contraire. Neuroscientists continue studying a link between aluminum and “neuropathology.” Here is just one example published in the journal Metabolic Brain Disease (online, July 27, 2017).

The authors point out that autistic spectrum disorder and Alzheimer’s disease may be impacted by a variety of factors from genetic to environmental.

In their words:

“One such environmental factor implicated as a potential cause in both syndromes is aluminium, as an element or as part of a salt, received, for example, in oral form or as an adjuvant. Such administration has the potential to induce pathology via several routes such as provoking dysfunction and/or activation of glial cells which play an indispensable role in the regulation of central nervous system homeostasis and neurodevelopment.

“The mechanisms whereby environmental aluminium could contribute to the development of the highly specific pattern of neuropathology seen in Alzheimer’s disease are described. Also detailed are several mechanisms whereby significant quantities of aluminium introduced via immunisation could produce chronic neuropathology in genetically susceptible children. Accordingly, it is recommended that the use of aluminium salts in immunisations should be discontinued and that adults should take steps to minimise their exposure to environmental aluminium.”

Aluminum in the Brain?

Researchers have known for years that aluminum accumulates in the brains of people with Alzheimer’s disease. How and why it gets there has been a mystery.

We found this article in the Journal of Trace Elements in Medicine and Biology (March, 2017) particularly intriguing:

“…we do not know the cause of Alzheimer’s disease and environmental factors may yet be shown to contribute towards its onset and progression. One such environmental factor is human exposure to aluminium and aluminium has been shown to be present in brain tissue in sporadic Alzheimer’s disease. We have made the first ever measurements of aluminium in brain tissue from 12 donors diagnosed with familial Alzheimer’s disease. The concentrations of aluminium were extremely high…

“…The unique quantitative data and the stunning images of aluminium in familial Alzheimer’s disease brain tissue raise the spectre of aluminium’s role in this devastating disease.

“…Aluminium is neurotoxic and the concentrations of aluminium found in these familial AD [Alzheimer’s disease] brains are unlikely to be benign and indeed are highly likely to have contributed to both the onset and the aggressive nature of any ongoing AD in these individuals. These data lend support to the recent conclusion that brain aluminium will contribute towards all forms of AD under certain conditions.”

What to Make of This?

We would be the first to admit that there is no definitive proof that using an aluminum antiperspirant increases the risk of Alzheimer’s disease. That said, most people rely on such products daily (and sometimes multiple times a day) for years or decades. We do not know the impact of such regular use on the body or brain. We do know that researchers have been calling aluminum a neurotoxin for years.

Is Aluminum Absorbed Through the Skin?

This is a very controversial topic. A study published in Clinical and Translational Science (Nov. 2018) revealed that 2 out of 12 healthy women tested with an “extremely rare isotope of aluminum (26 Al) chlorohydrate” had detectable levels in their blood.

The authors of this study cited previous findings published in the journal Food and Chemical Toxicology (Feb. 2001):

“In selected blood samples, 26Al could be detected at very low levels by AMS [accelerated mass spectroscopy]; however, the concentrations found were too low to provide solid quantitative data. In urine, 26Al was detected in the first day and continued for at least 44 days. Most of the urinary excretion occurred over the first 2‐week postexposure.”

Following up on that research, investigators also used radioactive labeled aluminum chlorohydrate. They found low levels of aluminum in 2 out of 12 blood samples and in 31% of urine samples.

A more recent study published in Toxicology Research (June 2022) also employed a radioactive aluminum antiperspirant formulation. The authors used a more powerful radiolabel 26Al form of aluminum. They concluded that the study “…shows that an extremely small amount [of aluminum] crosses the skin barrier.”

There was some evidence of radioactive aluminum in blood, urine and feces…though the authors minimized the importance of those observations. Their conclusion: “…the majority of the aluminum in the formulation was associated with the external layers of the skin without penetration through the skin.”

We do have one concern about this research, though. The authors seem to admit that there is some skin absorption of aluminum, but downplay its significance.

Under the “Conflict of interest statement” there is acknowledgement that five of the authors:

“are employed by their respective companies, each of which use Aluminium compounds in cosmetic products.”

The bottom line seems to be that aluminum is absorbed through the skin in small quantities. If people only used an antiperspirant occasionally, that might not be worrisome. But, as pointed out previously, people use these products daily for decades.

An article titled “The Postulated Innocuity of Lifetime Exposure to Aluminum Should be Reappraised” was published in Frontiers in Oncology (July 24, 2023).

The authors note:

“The debate on a potential role of aluminium in human carcinogenesis currently mainly concerns breast cancer, due to the presence of high concentrations of aluminium salts in cosmetics frequently applied to the breast area such as antiperspirants and sunscreens.”

The authors go on to raise some intriguing questions and concerns about chronic exposure to aluminum.

Aluminum vs. Magnesium:

Aluminum is not necessary for human biology. As far as we can tell it serves no essential purpose. Magnesium, on the other hand, is absolutely essential for human health. We could not function without magnesium. It is good for our bones, our heart and our blood vessels. Many people are deficient in this mineral.

When a reader told us that liquid milk of magnesia (magnesium hydroxide) was a great deodorant we were fascinated.

She wrote:

I want to share a remedy I learned about when traveling in Brazil. Just apply milk of magnesia to your armpits. It is the best underarm deodorant!”

Several years after we heard that milk of magnesia was especially helpful against body odor, we decided to try and come up with an easy applicator. We worked hard to eliminate the aluminum and the bleach (that used to be found in most drugstore milk of magnesia products) and find a roll-on system that would make MoM easy to apply.

Here is a video to explain more about this product.


Eventually our brilliant natural products chemist created a terrific unscented formulation. He also helped us develop an Aluminum-Free Men’s MoM formula with a fresh herbal fragrance.

With hot weather upon us, we are offering a Father’s Day special 25% sale on both of these aluminum-free 2 oz. deodorants. The discount code is POP25. It only applies to our Magnesium-Rich Aluminum-Free Roll-on 2 oz Deodorant and our Men’s MoM (Milk of Magnesia Aluminum-Free Roll-On Deodorant. This sale will only last through the end of June, 2024. Don’t forget the discount code POP25 when checking out!

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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