Aluminum-containing antiperspirants are safe and effective
No, they don't cause cancer, Alzheimer's, or "toxin buildup"
Well, it’s sweaty season here in Philly so questions about antiperspirants are creeping up. There is an extensive market of “aluminum-free” deodorants and antiperspirants, as well as rampant claims on social media about the harms of aluminum-containing antiperspirants, so it’s time we set the record straight.
The short answer? Aluminum-containing antiperspirants are safe for use and do not cause the myriad of health issues that circulate online.
Why do we use antiperspirants and deodorants?
Humans sweat in higher concentrations through our armpits as a temperature regulation mechanism. When we sweat, that fluid evaporates from the skin. The energy (in the form of heat) that is required to convert liquid sweat into water vapor means that heat is now transferred into the water vapor and means means that we feel cooler as a result.
This is called evaporative cooling. Chemistry!
However, at the same time, chemicals in sweat can serve as food for bacteria found on our skin. The metabolism of those chemicals can lead to odorous byproducts.
We have 2 main types of sweat glands: eccrine and apocrine.
Eccrine glands are found all over our body and produce sweat primarily composed of water and salts. Eccrine glands are activated when we are hot, during physical exertion, and when we are stressed (anyone else get the stress sweats? no? just me?)
Apocrine glands are predominantly found in areas of concentrated hair follicles, like the armpits and groin (think your pubertal hair growth regions). Apocrine sweat includes water and salts, but also contains proteins and lipids. Apocrine glands become activated during puberty.
Armpit odor, also called body odor (BO), is a result of bacterial metabolism of these sweat chemicals.
Remember: our skin has a microbiome, with key species from the genera Corynebacterium, Staphylococcus, and Micrococcus. When these bacteria use those proteins and lipids as food sources, they produce other chemicals as metabolic byproducts, including volatile organic compounds that have odors. These include fatty acids like 3-methyl-2-hexenoic acid and sulfur compounds like thioalcohols.
Chemistry note: while volatile organic compound (VOC) is a phrase frequently slung around by wellness influencers to suggest this broad family of chemicals are inherently dangerous, the phrase merely means the substance is a carbon-containing chemical that evaporates at room temperature.
Deodorants and antiperspirants help manage the odors and sweat we produce.
Let’s quickly clarify the difference between deodorants and antiperspirants:
Deodorants are designed to reduce the smell of odors and do not combat the volume or amount someone sweats. Armpit odor is caused by the metabolic processes of the bacteria that live on your skin, so deodorants typically contain ingredients that combat the bacteria themselves: antimicrobial compounds like alcohols, triclosan, and other antibacterials. Deodorants may also include fragrance chemicals that aid in masking any residual odor.
Antiperspirants are designed to reduce the amount of sweat itself. As a consequence of that, you ALSO reduce odor, as there is less sweat for the bacteria to feed off of. This process is facilitated through a different chemical reaction: one with the ingredients in the antiperspirant and the water in your sweat.
Aluminum salts are the active ingredient in antiperspirants, but not deodorants.
Antiperspirants use salts - the chemistry term for ionic compounds - to reduce the volume of sweat. These salts are typically aluminum-containing compounds like aluminum chloride, aluminum chlorohydrate, or aluminum zirconium.
When the salts are applied to the skin, they spread across the pores of sweat glands. The salts react with the water in sweat and dissolve from a spreadable solid into a gel-like substance that covers and plugs the sweat gland. This plug reduces the volume of sweat that can escape from the sweat gland. This is a temporary process, and the antiperspirant is not being absorbed by the skin.
Today, many products are combined antiperspirants and deodorants. Those will contain combinations of both products to mitigate sweat itself, as well as odor.
Aluminum-containing salts are NOT elemental metal aluminum
Most of the claims relating to the harms of antiperspirants revolve around aluminum. Unfortunately, while these claims sound scary, they are completely false. More than that, they confuse elemental, or metal aluminum, with the aluminum salts contained in antiperspirants.
If you recall from this piece on vaccines and mercury and this one on fluoride, you’ll remember that:
Chemical compounds are not the sum of their elemental parts. The identity, nature, behavior, and metabolism of these chemicals change when they are in compound form.
I use table salt as a common example: another ionic compound with a metal ion (sodium) and a halogen (chloride), that is WILDLY different than elemental metal sodium and elemental chlorine gas.
The same is true for these antiperspirant ingredients: the metal ion, Aluminum ion is Al3+, and that is not the same as elemental aluminum. Aluminum ions react with the negative ions to form salts. For example, Al2Cl(OH)5 (dialuminium chloride pentahydroxide) contains (2) Al3+ ions and a Cl(OH)5 (with a 6- charge).
Keep this in mind when evaluating claims you hear about “aluminum in deodorant” online.
Aluminum is everywhere.
Aluminum metal is the most common metal on Earth and makes up about 8% of the Earth’s mass. Adults naturally have between 30 to 50 milligrams of aluminum in their body at any given time, simply through living. Aluminum - primarily in salt forms - is found ubiquitously in the soil and water.
As a result, aluminum compounds are naturally found in food and water, and adults generally consume between 7 and 9 milligrams of aluminum per day. But guess what? Your excretory system removes 99% of the aluminum you are exposed to, because there aren’t many biological processes that it is needed by. Your kidneys and your tightly regulated physiological processes are always doing their jobs.
Aluminum salts are also found in certain medications like antacids and anti-ulceratives, as well as cosmetic products and certain kitchen products.
In antiperspirants, over the counter products typically contain aluminum chloride, aluminum chlorohydrate, and aluminum zirconium in concentrations ranging from 10% to 25% by weight. These compounds are not absorbed by the skin: studies estimated that *maybe* between 0.01% to 0.06% of aluminum salts applied to skin are actually absorbed.
As such, if you’re using an aluminum-containing antiperspirant, you are maybe absorbing between 4 to 10 micrograms of aluminum per day (0.004 to 0.010 milligrams).
The 7 to 9 milligrams of aluminum you consume daily through food and water is at least 700 times MORE than any possible absorption you’d have through antiperspirant use.
As such, you do not need to be concerned about aluminum exposure through antiperspirant.
Aluminum salts in antiperspirants do NOT pose a risk to your health.
Since we know the dose makes the poison, we understand that we don’t need to be concerned about this microgram-quantity of aluminum in antiperspirants. But let’s dig into the common claims that circulate online.
I pulled this from “JetSetBabe” who is *definitely not* qualified to speak on these topics.
First: deodorants do not contain aluminum salts. So if you ever see that on a claim, you know that it is already misinformation.
Next: if you see claims making statements about toxicity without context, you know that’s a red flag from my article here.
Third: the dose makes the poison. JetSetBabe does not seem to understand that, with any of the claims on this graphic.
Finally: Antiperspirants are regulated by the FDA as over-the-Counter (OTC) drugs. This means they are regulated for safety and efficacy. This is because they contain active ingredients (such as aluminum-based compounds) that temporarily reduce sweat production by blocking the sweat glands. As such, these products are subject to an array of scrutiny, including clinical trial data for effectiveness, toxicology data for safety, and ongoing study after a product has entered the market.
But let’s dig into the claims about aluminum.
Aluminum-containing antiperspirants are not causing breast cancer.
Rumors on the internet claim that aluminum salts in antiperspirants applied in proximity to breast tissue cause breast cancer. This is not supported by evidence.
A systematic review concluded that not only is there no evidence of breast cancer linked to antiperspirant exposure, but there is also no evidence linking aluminum exposure through consumption in food and water to breast cancer.
While a case-control study is frequently cited to support claims related to antiperspirants and breast cancer, numerous meta-analyses have refuted this. More than that, studies have demonstrated that the levels of aluminum found in breast tumor tissue are the same as those found in normal tissue.
Several studies have sought to investigate potential causal relationships and there have been no data that indicates use of antiperspirants is linked to breast cancer in any way. Metal aluminum, aluminum oxides, and aluminum salts have not been shown to be genotoxic (damaging to DNA) or carcinogenic.
The National Cancer Institute, the American Cancer Society, and other professional organizations state that there is: no scientific evidence that links the use of deodorants & antiperspirants to the development of breast cancer.
Antiperspirants don’t block toxins from being removed from your body.
Another common claim is that it isn’t the aluminum in the antiperspirants, but it’s the fact that you are blocking toxin removal by inhibiting sweating. This causes cancer-causing toxins to build up in the lymph nodes and therefore causes you to develop cancer.
This is not true, and unfortunately, demonstrates a lack of understanding of physiology. Sweating is for temperature regulation, not toxin removal. If you temporarily block a selection of sweat glands in your armpits, you have other sweat glands across your body to aid in temperature regulation.
Potentially harmful levels of chemicals (some which could be considered toxins) are removed from your body through the constant filtration of blood and excretion via your kidneys, liver, GI tract, and lungs. You typically will exhale certain waste products (like carbon dioxide), and others are removed in your urine or feces. That’s why measuring urine levels of chemicals (like chlormequat) are not appropriate measures to assess toxicity, since your body is removing these substances in the way it’s supposed to.
Temporarily blocking sweat in your armpits is not going to lead to this type of response.
While people use the fact that many breast cancers develop in the upper and outer regions of the breast, regions closest to the armpit, this is a function of anatomy: breast tissue tends to be dense there. Dense breast tissue is more challenging to screen and detect early stage cancers, and there is a link between dense breast tissue and cancer risk, not the proximity to where you apply antiperspirant.
Aluminum-containing antiperspirants are not causing Alzheimer’s disease.
Another claim which really began in the 1960s, where some studies observed higher levels of aluminum in brain tissue of Alzheimer’s patients. This of course, led to a lot of public outcry and fear, and extensive scrutiny of consumer products that contained aluminum.
The good news? There is no causal evidence to suggest that aluminum exposure - in food, water, or consumer products - is linked to increased risk of Alzheimer’s disease.
Decades of research have attempted to replicate this finding or determine a causal relationship and have failed to do so. The current understanding of Alzheimer’s disease suggest a strong genetic contribution, processes and cellular damage that occur during the aging process, lifestyle factors, and other underlying medical conditions. None of these are related to aluminum exposure, through food, water, or consumer products.
While reviews identify an association between aluminum in the brain and Alzheimer’s disease, it actually appears that Alzheimer’s disease may lead to the accumulation of aluminum, not the other way around.
That’s why the Joint Expert Committee on Food Additives (JECFA) of the World Health Organization, the Alzheimer’s Association, the Alzheimer’s Society, and the CDC’s Agency for Toxic Substance and Disease Registry have all concluded the evidence does not demonstrate a link.
What about if I have kidney disease?
Excess aluminum is filtered out through the work of your kidneys. As such, antiperspirant labels must carry an FDA warning: "Ask a doctor before use if you have kidney disease."
However, this warning is specifically for people whose kidneys are functioning at 30% or less (dialysis patients), which are patients that are going to have a lot of medical considerations.
While this warning exists, remember: the vast majority of aluminum exposure is through food and water. Less than 10 micrograms might possibly be absorbed through skin use of antiperspirants. As such, experts have concluded that it is almost impossible to absorb enough aluminum to harm kidneys through the use of antiperspirants, but this warning is part of the regulatory conscientiousness of the FDA.
You do not need to fear or be worried about aluminum-containing antiperspirants.
Unfortunately, social media has given people a megaphone to speak on topics they don’t understand. This, plus low science literacy and the mischaracterization of scientific studies by media outlets, has led to undue fear and anxiety about perfectly safe products.
There is no scientific evidence that aluminum, or any of the other ingredients, in antiperspirants or deodorants pose any threat to human health.
If you’re not a sweaty person and don’t see a need for antiperspirant, that’s great! Use what you enjoy and works for you. But if you need it, don’t fear it.
Me personally? I use Old Spice two-in-one.
Thanks for joining in the fight for science!
Thank you for supporting evidence-based science communication. With outbreaks of preventable diseases, refusal of evidence-based medical interventions, propagation of pseudoscience by prominent public “personalities”, it’s needed now more than ever.
Stay skeptical,
Andrea
“ImmunoLogic” is written by Dr. Andrea Love, PhD - immunologist and microbiologist. She works full-time in life sciences biotech and has had a lifelong passion for closing the science literacy gap and combating pseudoscience and health misinformation as far back as her childhood. This newsletter and her science communication on her social media pages are born from that passion. Feel free to follow on Instagram, Threads, Twitter, and Facebook, or support the newsletter by subscribing below:
Hi Dr Andrea --first of all I love your work --you're doing such important outreach! I really hope that the people who need to hear this (read the entire "Wellness world") will one day access your rich knowledge and straightforward presentation of information!
I was just watching a documentary on the Love Canal on PBS and it occurred to me that as with all misinformation, there is a kernel of truth there. I'm old enough to remember the Love Canal disaster and the Superfund clean-ups that happened as a result --the EPA was in its infancy (oddly now somewhat gutted, but that's another topic) --and people were -rightfully so- terrified of the chemical mess that the unregulated chemical companies dumped into our water and buried under our communities. So though I completely share your dismay at the rampant chemophobia out there in the world today --it occurs to me that there was good reason to fear the companies that put profits above people's safety at that time (from the 1950's well into the 80's) and so I can in a way understand the general public's distrust of all things "chemical" (and yes, i get that everything is chemicals) but we were terrorized by the misbehavior and complete refusal of companies like Hook Chemicals to be accountable for polluting our environment and hurting our children. It took a massive movement of mostly mothers to hold them to account and to make the government and the chemical companies start to pay attention to what they were doing to our environment. I think sometimes today we can take for granted how much more regulated the chemical industry is compared to back then --but that memory runs deep and so though that mistrust seems silly and unwarranted --it was born of a real problem with "chemical" contamination of the environment; and it was not that long ago!
I wonder how we can acknowledge peoples' fears and distrust of those companies who put profits over peoples' and the environment's health, while bringing them into the 21st century of much more regulated and tested synthetic chemicals. My husband works in agriculture and I know first hand how things have changed --and how much less toxic many of the newer pesticides are; but I think the trauma of having lived through those Superfund site clean-ups may be why people are so hesitant to embrace a new generation of medical and ag synthetics. (And of course --i get that many "natural" chemicals are more toxic than the synthetic ones; but i think that the appeal to nature fallacy may well have some of its roots there as well (as well as in pre-WWII Germany...).
Just some thoughts. Thank you for all you do!
Another great piece, though having dealt with the claim for many years in my professional life, it saddens me to think about how many times this perspective has been provided over the years and we still see the rumors/allegations circulating Unfortunately, marketers that are willing to sell products based on the fear are a major factor.