Antiperspirant/Deodorant Sticks: Science, History, and Manufacturing Insights

Background

Antiperspirant/deodorant (APD) sticks are the most common form of personal care products used to manage underarm wetness and body odor. They combine active drug ingredients with a wax‑based matrix, oils, and silicones, which are then molded into a convenient stick shape.

How Body Odor Forms

Underarm sweat glands secrete a clear fluid that contains natural lipids. These lipids serve as a food source for skin bacteria, which metabolize them into volatile compounds such as isovaleric acid—responsible for the characteristic “sweaty” scent.

Deodorants vs. Antiperspirants

Deodorants aim to reduce odor by killing or inhibiting odor‑producing bacteria. They do not alter sweat production. Antiperspirants, classified as drugs by the FDA, reduce perspiration by forming temporary plugs in sweat gland ducts. The resulting lower moisture level also diminishes bacterial activity and odor.

History

Humans have long used fragrances to mask body odor, but the first chemical control dates back to the late 19th century. Mum (1888) was the first trademarked antiperspirant, a waxy cream that was difficult to apply. Everdry introduced the first aluminum chloride formulation a few years later. Throughout the 20th century, the market expanded to creams, solids, pads, dabbers, roll‑ons, and powders.

In the 1950s and 60s, aerosol dispensers revolutionized the industry. Gillette’s Right Guard (1962) was the first aerosol antiperspirant, allowing hands‑free application. By 1967, aerosols accounted for half of U.S. sales, reaching 82% by the early 1970s.

Regulatory changes in the late 1970s—an FDA ban on aluminum zirconium complexes in aerosols and an EPA restriction on CFC propellants—eroded consumer confidence. Aerosol sales fell to 32% by 1982, while stick formulations, previously only 4% of the market, surged to over 35% by the mid‑1980s and remain the dominant format today.

Raw Materials

Active Ingredients

Approved by the FDA under the OTC Drug monograph, the main active agents are aluminum chlorohydrate, aluminum chloride, aluminum sulfate, and aluminum zirconium complexes. The most prevalent is aluminum zirconium tetrachlorohydrex glycine, used at 8–25% by weight.

Gelling Agents

Waxy or fatty bases such as stearyl alcohol, cetyl alcohol, hydrogenated castor oil, and glyceryl stearate provide the stick’s structure. These are blended with lubricating oils and silicone emulsifiers (e.g., cyclomethicone) to give a smooth, dry finish. Powders like talc or starch help control viscosity and impart a crisp feel.

Other Ingredients

Fragrances, colorants, and specialty additives enhance sensory appeal. Some brands incorporate time‑released fragrances or cosmetic ingredients that, while not functional, improve consumer perception.

The Manufacturing Process

Batching

• Ingredients are combined in a jacketed stainless‑steel kettle. Steam heat melts the matrix while the mixture is stirred. Temperature control prevents scorching of the waxes.
• Once all components are added, the batch is blended until uniform.

Filling

• Sticks are housed in hollow tubes equipped with an elevator platform that moves up or down to dispense the product. The platform may be manual or screw‑driven.
• The molten stick is poured slightly above its congealing point to ensure smooth flow without trapping air.

Finishing Operations

• Sticks pass under an infrared lamp to slightly melt the tops, smoothing the surface.
• A probe removes trapped air, and the stick is reheated to allow the product to fill the void.
• Rapid refrigeration solidifies the stick, and a top or bottom cap seals the container.
• Final cleaning stations remove any residue before cartons are filled for shipment.

Quality Control

Safety Testing

Guidelines from the Cosmetics, Toiletries, and Fragrance Association (CTFA) help manufacturers assess skin irritation, contact sensitization, photodermatitis, and toxicity (inhalation or ingestion).

Efficacy Testing

Antiperspirants must reduce sweat by at least 20% per the OTC monograph. Common tests include:

• Visualization technique: The skin is painted with iodine‑castor oil, dried, and coated with starch. Sweat spots appear as dark patches on a white background.
• Silicone film method: A silicone film is peeled after induced sweating; holes indicate sweat excretion.
• Infrared gas sensors: Moisture loss is detected by passing a gas stream over the armpits.
• Gravimetric methods: Sweat is collected on cotton pads and weighed.

Byproducts and Waste

During filling, overfilling or spillage can generate scrap. Scrap is typically returned to the batch for remelting, with occasional re‑assaying to confirm quality. Solvents or fragrances lost during reheating are replenished before refilling. Any contaminated material is disposed of in line with local regulations.

The Future

Clear APD sticks gained traction in the 1990s. After early stability challenges, Bristol‑Myers’ Ban for Man (1993) and Gillette’s Cool Wave gel‑stick cemented the format’s commercial viability. Today, clear sticks and gel‑sticks continue to evolve, offering consumers a cleaner aesthetic and advanced performance.