Deodorant Without the Fear Marketing

The underarm has somehow become a small battlefield in the wellness wars.

One side warns that aluminium deodorants cause breast cancer. Another insists that crystal deodorants are natural, aluminium-free and therefore safer. Then there are the baking-soda devotees, the essential-oil evangelists and the people who appear to believe that smelling faintly of onion is evidence of metabolic purity.

Most people want something simpler. They want to smell presentable without making their underarms sting, itch or gradually turn darker.

The sensible question is not whether a deodorant is “natural.” It is whether it controls odour without repeatedly irritating an area of skin that is shaved, folded, warm and occluded for much of the day.

First, deodorant is not antiperspirant

Sweat itself is not usually the main source of body odour. The smell develops when microorganisms living on the skin break down components of sweat and other secretions into volatile compounds.

Antiperspirants reduce the amount of sweat reaching the skin, usually with aluminium-based salts that temporarily obstruct the sweat ducts. Deodorants work differently. Depending on the formulation, they may influence odour-producing bacteria, interfere with the formation of malodorous compounds, absorb moisture or bind odour molecules so that they are less perceptible.

This distinction matters. A deodorant may help you smell fresher while allowing normal sweating to continue. It should not be judged as a failed antiperspirant simply because the underarm still becomes damp during a Singapore afternoon.

Does deodorant cause breast cancer?

There is no convincing scientific evidence that deodorant or antiperspirant use causes breast cancer.

Aluminium-containing antiperspirants have attracted concern because they are applied close to breast tissue and because aluminium compounds have been investigated for possible hormonal effects. These are reasonable questions to study. They are not proof of harm.

The US National Cancer Institute states that studies have not confirmed a substantial adverse effect from aluminium in antiperspirants that would increase breast-cancer risk. A large interview-based study involving 813 women with breast cancer and 793 controls found no increased risk associated with deodorant or antiperspirant use, including use shortly after shaving.

Choosing an aluminium-free deodorant is perfectly reasonable if you prefer to sweat naturally or find antiperspirants irritating. It should be presented as a formulation choice, not as cancer prevention.

Fear is an excellent marketing preservative. It keeps dubious claims fresh for years.

Why underarms become irritated and darker

Axillary skin has a difficult working environment. It experiences friction from clothing and skin folds, frequent shaving or plucking, sweat, occlusion and repeated application of the same product.

Research examining shaving found that it removes stratum-corneum material along with hair. More frequent shaving was associated with greater visible irritation. Reviews of axillary skin biology also describe how repeated irritation can lead to post-inflammatory hyperpigmentation, particularly in susceptible skin types.

A recent systematic review of axillary hyperpigmentation identified irritation and inflammation from friction, shaving, plucking, deodorants and even aggressive lightening products as potential contributors.

This does not mean every dark underarm is caused by deodorant. Pigmentation can also be associated with acanthosis nigricans, eczema, infection and other dermatological or metabolic conditions. Sudden, marked or velvety darkening deserves proper assessment rather than increasingly determined scrubbing.

But when pigmentation follows itching, burning, redness or recurrent peeling, reducing irritation is a logical first step. It is generally easier to prevent inflammation than to treat the pigment it leaves behind.

“Natural” deodorant is not automatically gentler

The word natural tells us where an ingredient may have originated. It tells us very little about whether a particular person will tolerate it.

Fragrance is a recognised cause of axillary allergic contact dermatitis. In one provocation study of fragrance-sensitive individuals, 12 of 20 deodorants previously associated with a rash produced eczema during repeat-use testing. The reactions occurred particularly readily in the axilla.

Essential oils can contain the same fragrance allergens found in conventional perfume. There are also published reports of allergic contact dermatitis from products specifically marketed as natural deodorants.

Baking soda is another popular natural-deodorant ingredient. Some people tolerate it perfectly well. Others develop burning, redness or peeling, particularly after shaving or when it is used at a high concentration in a strongly alkaline formula.

Natural remains a description of origin, not a certificate of good behaviour.

What about crystal deodorant?

Crystal deodorants are often presented as an aluminium-free alternative. Most are made from potassium alum or ammonium alum. These are aluminium salts.

They are chemically different from aluminium chlorohydrate and the aluminium-zirconium salts commonly used in antiperspirants, and they may behave differently on the skin. But describing an alum crystal as aluminium-free is inaccurate. Reviews of deodorant ingredients list potassium alum among aluminium-containing deodorant materials.

Crystal deodorants are not inherently dangerous, and many people use them without difficulty. They are also not universally non-irritating. Published reports describe irritant axillary dermatitis, allergic contact dermatitis and granulomatous dermatitis associated with alum-containing crystal deodorants. These are case reports rather than evidence of widespread harm, but they are enough to disprove the idea that a crystal format guarantees gentleness.

A quieter formulation approach

This was the thinking behind UN/05 Daily Deodorant.

UN/05 is a waterless deodorant stick. It contains no added fragrance, essential oils, sodium bicarbonate or aluminium salts. It is designed to manage odour rather than prevent normal sweating.

Instead of relying on perfume to cover odour, the formula uses several complementary mechanisms:

• Zinc ricinoleate binds odour-active compounds, making them less perceptible. It has a long history of use as an odour absorber in deodorant formulations.
• Triethyl citrate is commonly used in deodorants to interfere with the processes involved in malodour formation.
• Magnesium hydroxide contributes to the deodorising system without using sodium bicarbonate, while tapioca starch absorbs some excess surface moisture.

The product remains a deodorant, not an antiperspirant. It will not — and should not claim to — switch off sweat glands.

The emollient base contains caprylic/capric triglyceride, coco-caprylate/caprate and bisabolol to help the stick glide without the abrasive drag that can be uncomfortable on recently shaved skin.

Its waterless format also means the product does not require a conventional water-phase preservative system. Low-water-activity cosmetics may be considered microbiologically lower risk, although that does not remove the need for good manufacturing, microbial assessment and stability testing.

This is an important distinction. “Preservative-free” should not be used to imply that approved cosmetic preservatives are poisonous. In water-containing products, an effective preservative system is often what prevents the product from becoming a small laboratory experiment in the bathroom.

The sensible verdict

There is no evidence-based reason to fear ordinary deodorant as a cause of breast cancer. There is, however, a good dermatological reason to pay attention to irritation.

Underarm skin is exposed to shaving, friction, sweat and daily product application. A fragranced or highly alkaline formula may be perfectly acceptable for one person and troublesome for another. Once recurrent inflammation begins, itching and discomfort may be followed by post-inflammatory pigmentation.

UN/05 is not a medical treatment for dark underarms, nor is it a promise that nobody will ever react to it. No responsible cosmetic should make that promise.

It is a deliberately restrained deodorant: aluminium-salt-free, fragrance-free, essential-oil-free and baking-soda-free, with an odour-control system that does not depend on disguising one smell with another.

Sometimes better skincare begins with adding an active. Sometimes it begins with removing the ingredient that was causing the trouble.

References

• National Cancer Institute, Antiperspirants/Deodorants and Breast Cancer fact sheet — cancer.gov
• The case-control study of 813 women with breast cancer and 793 controls, the research on shaving and axillary irritation, the fragrance provocation study, the systematic review of axillary hyperpigmentation and the case reports of dermatitis associated with alum crystal deodorants are indexed on PubMed and PubMed Central.
• ISO guidance on microbiological risk assessment for cosmetics of low water activity — iso.org

Shop the products

• un/extra UN/05 Daily Deodorant — waterless, aluminium-salt-free, with no fragrance or baking soda.
• un/extra UN/01 Soft Wash — a thirteen-ingredient cleanser with no fragrance or essential oils.
• PURITY — a calming gel for skin that has been provoked.

Every product page publishes its full ingredient list, in order. Free delivery within Singapore on orders of S$100 and above.