Is an antiperspirant carcinogenic?

When applied to the skin, aluminium salts precipitate and bind with dead skin cells, forming plugs that block the sweat glands and thus inhibit perspiration. Furthermore, aluminium salts are bactericidal. They therefore eliminate the bacteria that are present in large quantities in the armpits, which are the source of unpleasant odours.

According to the European cosmetic regulation,the concentration of aluminium salts in deodorants must not exceed 20%, which corresponds to approximately 5% aluminium content.

In the early 2000s, a steady increase in breast cancer among increasingly younger subjects raised concerns among researchers and authorities. The majority of tumours are located close to the armpit, a region that is near the lymph nodes and mammary glands, primarily exposed to deodorants.

Some scientists thus suspect that the aluminium salts present in certain deodorants are absorbed by the skin and cause changes in the oestrogen receptors located in the breast cells.

Thus, over the past decade in Switzerland, several studies have been conducted by Professor and Oncologist André-Pascal Sappino and Dr Stefano Mandriota. They exposed mouse mammary cells to aluminium salts (specifically AlCl3). The conclusions are unequivocal: aluminium salts promote the rapid development of sometimes aggressive tumours, forming metastases. However, one question remains: can we extrapolate the results obtained on animal subjects to humans?

Furthermore, shortly after, in June 2017, an Austrian studyshowed thatwomen who used analuminium salt deodorantseveral times a day on shaved armpits before the age of 30 had adoubled risk of breast cancer.

Despite this,a report from the ANSM (National Agency for the Safety of Medicines and Health Products) published in 2019 states the following conclusion: "the existing data does not allow us to establish a body of evidence in favour of a causal link between aluminium and breast cancer", but it "does not allow us to definitively exclude it".

Furthermore, the SCCS (Scientific Committee on Consumer Safety in Europe) published a report in 2019 confirming the extremely low skin absorption (around 0.00052%) of aluminium salts, even on shaved or waxed skin. According to this document, the aluminium present in antiperspirants remains outside the body, preventing any toxic effect. The SCCS therefore considers that exposure to aluminium through daily applications of cosmetics containing it does not increase the body's aluminium load from other sources. The concentration of aluminium "absorbed" by the skin would be far too low to play a role in the development of breast cancer.

In conclusion, it is challenging to form an opinion on the harmfulness of aluminium salts in antiperspirants. As a precautionary principle, at Typology, we exclude these compounds from our formulas.

In March 2020, the CSSC established several dosage recommendations:

• 6.25% in non-spray antiperspirants;

• 10.60% in sprays;

• 2.65% in toothpastes;

• 0.77% in lipsticks.

It should be noted, the ANSM recommends a much lower concentration: it advises to not exceed a content of 0.6% aluminium salts in cosmetic products.

Nevertheless, it is important to clarify that these are merely guidelines: they do not result in a change to the regulations.

To detect the presence of aluminium in a deodorant, one must pay particular attention to the list of ingredients displayed on the packaging or container (I.N.C.I. list). Indeed, beauty care regulations demand this transparency from brands. The ingredients must be listed in descending order according to their quantity. Aluminium salts and their derivatives can be identified on the I.N.C.I. lists under the following names:

• Aluminium Chloride;

• Aluminium Chlorohydrate;

• Aluminium Chlorohydrate;

• Aluminium Sesquichlorohydrate;

• Aluminium Zirconium.

However, not all deodorants contain aluminium. Many consumers are now turning to "aluminium-free" formulas, enriched for example with baking soda or even clays such as diatomaceous earth powder.

In response to the negative publicity associated with aluminium salts, alum stone has carved out a place for itself in the bathroom. However, it is not as natural as its name might suggest. In fact, it can sometimes be a 100% synthetic stone, manufactured fromAmmonium Alum or synthetic Ammonium Sulphate, a by-product of the nylon chemical industry. In any case, whether natural or synthetic, alum stone contains aluminium salts.

The solution, therefore, lies in the use of deodorants with clean formulas, made from natural ingredients that are environmentally friendly and health-conscious. Today, it is possible to find deodorants with healthy compositions, available in spray, roll-on, stick forms, or those that can be applied directly with the finger.

• SAPPINO A-P. & al. Aluminium chloride promotes tumorigenesis and metastasis in normal murine mammary gland epithelial cells. International Journal of Cancer (2016).

• KREWSKI D. & al. Systematic review of potential health risks associated with pharmaceutical, occupational and consumer exposure to metallic and nanoscale aluminium, aluminium oxides, aluminium hydroxide and its soluble salts. Critical Reviews in Toxicology (2014)

• Scientific Committee on Consumer Safety: SCCS/1613/19 (2019).

• Risk assessment related to the use of aluminium in cosmetic products - Information note - ANSM: National Agency for the Safety of Medicines and Health Products.