Letter to the Editor: Critique of 'Safer Sweat Control' Article


To the Managing Editor of Cosmetics & Toiletries:

I read the article “Safer Sweat Control” in the January 2020 issue of Cosmetics & Toiletries magazine, and would like to offer some critical comments based on my extensive knowledge and intimate involvement with all aspects of antiperspirant and deodorant technology for 31 years.

I support the development work done to date by the authors to identify and validate alternative options to keep the underarms dryer, particularly if the product approach is considered as cosmetic in effect and not an OTC drug action. The use of an effective absorbent as referenced in the article would represent such an approach. Of course, the final product execution would also have to exhibit acceptable consumer aesthetics.

However, I believe the article contained several examples of overstated/misleading statements concerning the lack of safety of the current aluminum-based antiperspirant actives that are the current global industry standard, and which I now wish to address in some detail.

Aluminum Safety

1) The title “Safer Sweat Control” definitely implies that the aluminum salts are less safe, and this is simply not supported by official publications and available data. Two examples follow:

a) The EU SCCS (Scientific Committee on Consumer Safety) published a preliminary opinion on the safety of aluminum in cosmetic products in March 2014. At that time, they requested from the industry more definitive data on the internal exposure to aluminum after topical skin application using human exposure studies under use conditions.

Most recently, in October 2019, the SCCS published a more definitive opinion based on the consideration of all new data, and their conclusions are presented verbatim below.

The SCCS agrees ... that use concentrations of aluminum compounds in antiperspirants (at doses up to 20% ACH) will not lead to skin irritation in consumers. Note that ACH stands for aluminum chlorohydrate. The need for this clarification will appear later in this communication.

In light of the new data provided, the SCCS considers that the use of aluminum at concentrations of 6.25% and 10.60% in non-spray antiperspirants and spray antiperspirants, respectively, is safe. Note that these are typical maximum levels found in products.

The SCCS considers that the systemic exposure to aluminum via daily applications of cosmetic products does not add significantly to the systemic body burden of aluminum from other sources.

So clearly, the use of aluminum in antiperspirants in concentrations that comply with the limits set by European regulations is safe for human health.

b) In reviewing the U.S. Food and Drug Administration (FDA) Adverse Events Reporting System (FAERS) public dashboard, one will find that the most frequently reported adverse events are associated with hair care (shampoos, conditioners, hair dyes, hair smoothing products), baby products and personal cleaning products. In fact, from 2015 to 2019, there were only a total of six cases for antiperspirants-deodorants that were identified as “serious.”

Aluminum Chlorohydrate, Chloride and HCl Production

2) There are references in the article to "traditional aluminum chloride-based salts" that result in "a significant amount of hydrochloric acid (HCl) [being progressively released], which can cause skin irritation ... " Clearly, this contradicts what the SCCS has recently concluded and published.

a) Aluminum chlorohydrate (ACH) is the traditional active ingredient in marketed antiperspirants, not aluminum chloride. This can be easily confirmed by checking the ingredient labeling on products marketed in the U.S. and Europe by Unilever, Beiersdorf, Henkel, L’Oréal, P&G, Colgate, etc.

b) There are no major marketed underarm brands that utilize aluminum chloride. AlCl3 is classified as corrosive and irritating to the eyes, skin and mucous membranes. It can cause irreversible damage, and as such, it is placed in a different GHS hazard classification than ACH. When ACH does result in skin irritation, it is reversible or transient. It is interesting to note that the mean primary irritation scores for ACH in 48-hr occluded patch tests are well below those for sodium lauryl sulfate, and often quite comparable to physiological saline.

Admittedly, AlCl3 is used in a few Rx products in the U.S., and in some products positioned for hyperhidrosis in Europe, but they all have special use and precaution instructions.

c) Let’s now address HCl generation. The chemistry of aluminum compounds in water can be complex. If a small amount of water is added to anhydrous aluminum chloride, a hissing sound is emitted and HCl gas will be given off as acidic fumes.

However, if aluminum chloride is dissolved in a large amount of water, as it would be in a hyperhidrosis product, for example, the solution is acidic but it has nothing to do with the formation of hydrochloric acid. An aluminum hexaqua complex ion is formed [Al(H2O)6]3+ along with Cl- ions. The complex ion gets deprotonated, causing the solution to be acidic due to the formation of hydroxonium ions H3O+.

Industry Efforts

3) Finally, the statement "the industry has moved to eliminate soluble aluminum from antiperspirants" implies a negative industry action, which has not happened. The fact is that the industry spent substantial funds to conduct expensive safety studies so that the aluminum content of cosmetics would not have to be restricted. The quoted statement provides a disservice to readers.

I understand that the consumer press and the internet trade in unsubstantiated reports about aluminum compounds, but the fact is that the industry has not moved away from aluminum-containing antiperspirants. Almost all of the global marketers launched new antiperspirants in 2019, many formulated to deliver higher levels of sweat protection. What the industry has done is introduce a myriad of deodorant products that claim “aluminum-free,” but we know that pure deodorants  have never contained aluminum.  These are marketing tactics to gain shelf facings.


In conclusion, it is my opinion that there is no reason to include statements alluding to safety concerns with current antiperspirants, that in fact are refuted, in an article dealing with a new and potentially interesting sweat control approach.

I hope that the work with the hydroxyapatite mineral is eventually proven out on its own technical merits.

-Philip B. Klepak, Independent Consultant

More in Literature/Data