Aluminum Chlorohydrate: What It Is and Why It's Used (flagship)

Origin

Aluminium salts have been used as astringents — substances that contract body tissues — since antiquity. Their application to control perspiration was formalised in the late 19th and early 20th centuries, as the deodorant and antiperspirant market developed in the United States. Aluminum chlorohydrate specifically became the dominant antiperspirant active in the mid-20th century, replacing more aggressive aluminium chloride formulations that caused significant skin irritation.

Why It's Used

Aluminum chlorohydrate works by forming a gel plug in the sweat duct — temporarily blocking the flow of sweat to the skin's surface. This distinguishes it categorically from deodorants, which address odour but do not affect sweat production. In the United States, it is regulated as an OTC drug rather than a cosmetic, with maximum permitted concentrations and label wording mandated by the FDA monograph for antiperspirant drug products.

Elsewhere

Aluminium chlorohydrate is used in water treatment as a coagulant, helping to remove suspended particles from drinking water. Related aluminium salts are used in papermaking, dyeing, and as mordants in textile production.

What the Framework Sees

this profile *is* Question Zero, the same way Volume Two's flagship *was* Question 1.

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