Deodorants and antiperspirants

Deodorants and antiperspirants are personal hygiene products designed to reduce or mask body odour and control perspiration. While both serve to enhance freshness and comfort, they operate through different mechanisms—deodorants primarily neutralise odour caused by bacterial activity on the skin, whereas antiperspirants reduce the amount of sweat produced by the sweat glands. Their use has become an integral part of modern grooming habits, with growing attention to health, chemistry, and environmental impact.

Understanding Sweat and Body Odour

Human perspiration plays a vital role in regulating body temperature through evaporation. The skin contains two main types of sweat glands:

1. Eccrine glands: Found throughout the body, they secrete a watery, odourless sweat composed mainly of water and salts.
2. Apocrine glands: Concentrated in areas such as the armpits, groin, and scalp, these glands secrete a thicker fluid rich in proteins and lipids.

While sweat itself is odourless, body odour arises when bacteria on the skin—particularly Corynebacterium and Staphylococcus species—metabolise sweat components into volatile compounds such as fatty acids, ammonia, and sulfur-containing molecules. These compounds produce the characteristic unpleasant smell of body odour (bromhidrosis).

Deodorants: Mechanism and Composition

Deodorants are formulated to prevent or mask body odour without interfering with perspiration. Their action relies on antimicrobial agents, fragrance compounds, and deodorising chemicals.
1. Mechanism of Action:

• Antibacterial effect: Deodorants inhibit or destroy odour-causing bacteria on the skin surface using antimicrobial agents such as triclosan, chlorhexidine, or alcohols.
• Odour neutralisation: Some products contain substances like zinc ricinoleate, baking soda (sodium bicarbonate), or activated charcoal that absorb or neutralise odorous compounds.
• Fragrance masking: Essential oils and synthetic perfumes are added to provide a pleasant scent and mask residual odour.

2. Common Ingredients:

• Antimicrobial agents: Triclosan, ethanol, benzalkonium chloride.
• Deodorising agents: Zinc oxide, sodium bicarbonate, citric acid.
• Fragrances and essential oils: Lavender, sandalwood, citrus oils.
• Emollients and solvents: Propylene glycol, glycerine, and silicones for skin conditioning.
• Carriers and propellants: In aerosol sprays, liquefied gases such as butane or propane disperse the active ingredients.

3. Forms of Deodorants: Deodorants are available in multiple forms—sprays, roll-ons, sticks, gels, and creams—to suit user preference and skin type.

Antiperspirants: Mechanism and Composition

Antiperspirants are designed to reduce or block perspiration by temporarily sealing sweat ducts. Unlike deodorants, they address sweating itself, rather than the odour that results from it.
1. Mechanism of Action: The active ingredients, typically aluminium-based compounds, such as aluminium chlorohydrate, aluminium zirconium tetrachlorohydrex gly, or aluminium chloride, react with electrolytes in sweat to form gel-like plugs that block the openings of sweat glands. These plugs prevent sweat from reaching the skin surface. Over time, they are naturally shed as part of the skin’s renewal process.
2. Composition:

• Active agents: Aluminium salts (main antiperspirant agents).
• Astringents: Help contract skin tissue and close pores.
• Moisturisers: Counteract the drying effect of aluminium compounds.
• Fragrances and preservatives: Add scent and maintain product stability.

3. Application and Effectiveness: Antiperspirants are most effective when applied to clean, dry skin, typically at night when sweat gland activity is lower. Their effect can last up to 24–48 hours, depending on the formulation.

Differences between Deodorants and Antiperspirants

In many commercial products, deodorant and antiperspirant functions are combined, offering both odour control and sweat reduction.

Health and Safety Concerns

The widespread use of deodorants and antiperspirants has led to scrutiny regarding their long-term health effects and chemical safety.
1. Aluminium Compounds: Concerns have been raised about possible links between aluminium salts and health issues such as breast cancer and Alzheimer’s disease. However, extensive research by regulatory agencies, including the U.S. Food and Drug Administration (FDA) and the European Commission’s Scientific Committee on Consumer Safety (SCCS), has found no conclusive evidence of such associations when products are used as directed.
2. Parabens and Preservatives: Some deodorants contain parabens, synthetic preservatives suspected of being endocrine disruptors. Many manufacturers have moved towards paraben-free formulations in response to public concern.
3. Skin Sensitivity and Allergic Reactions: Fragrances, alcohol, and propellants can cause irritation or contact dermatitis, especially in individuals with sensitive skin. Hypoallergenic and alcohol-free alternatives are available for such users.
4. Triclosan Use: The antimicrobial compound triclosan has been restricted or banned in several countries due to concerns over bacterial resistance and environmental persistence. Natural antibacterial alternatives are increasingly favoured.

Environmental Considerations

Deodorants and antiperspirants also raise environmental concerns related to manufacturing, packaging, and chemical residues:

• Aerosol sprays release volatile organic compounds (VOCs) that contribute to air pollution and ozone depletion, though modern formulations have reduced such emissions.
• Plastic waste from roll-ons and sticks contributes to environmental pollution. Companies are now developing refillable or recyclable packaging.
• Biodegradable ingredients and plant-based formulations are gaining popularity in response to consumer demand for sustainable products.

Natural and Alternative Products

In recent years, there has been a rise in natural deodorants that avoid aluminium salts, parabens, and synthetic fragrances. These typically use baking soda, coconut oil, arrowroot powder, magnesium hydroxide, or essential oils as key ingredients.
While natural deodorants may not prevent sweating, they help neutralise odour and support skin health. Their efficacy varies, and users may need time to adjust during the transition from conventional products.

Regulatory Standards

Deodorants and antiperspirants are regulated as cosmetic or over-the-counter (OTC) products, depending on the jurisdiction:

• In the United States, antiperspirants are classified as drugs under FDA regulation because they alter the body’s function by reducing sweat.
• In the European Union, both deodorants and antiperspirants fall under the Cosmetic Regulation (EC) No. 1223/2009, which ensures safety testing and labelling.
• India regulates these products under the Drugs and Cosmetics Act, 1940, ensuring they meet safety and quality standards.

Cultural and Social Aspects

Personal hygiene practices involving deodorants and antiperspirants are influenced by cultural norms and climatic conditions. In warmer tropical regions, regular use is common due to higher perspiration rates. In recent decades, aggressive advertising and lifestyle branding have made these products symbols of personal confidence, grooming, and social acceptability.