The Science Behind 72-Hour Antiperspirant Protection

When a product claims 72-hour protection, it sounds like marketing hyperbole. But the science behind clinical-strength antiperspirants is genuine and well-documented. Here's how products like Mitchum actually deliver multi-day sweat protection.

How Sweating Works

Your body has between 2 and 4 million sweat glands. The eccrine glands, distributed across your entire body, produce the watery sweat that cools you down. The apocrine glands, concentrated in the underarms and groin, produce a thicker secretion that, when broken down by skin bacteria, creates body odour.

Sweating is a cooling mechanism — it's essential for regulating your body temperature. Antiperspirants don't stop this process entirely. They reduce sweat output in the specific area where they're applied (typically 20-30% reduction), which is enough to prevent visible wetness and reduce the substrate that bacteria feed on.

The Aluminium Salt Mechanism

The active ingredient in all antiperspirants is an aluminium salt — most commonly aluminium chlorohydrate or aluminium zirconium tetrachlorohydrex gly. When applied to the skin, these salts dissolve in the thin layer of moisture on the skin's surface and are drawn into the sweat duct.

Inside the duct, the aluminium ions interact with proteins to form a temporary gel-like plug. This plug physically blocks the duct, preventing sweat from reaching the skin's surface. The plug is shallow — it sits in the top portion of the duct and doesn't penetrate deeply into the gland itself.

Why 72 Hours?

The gel plug formed by clinical-strength formulas is more robust than standard antiperspirant plugs. Mitchum's formula uses a higher concentration of active ingredients combined with an optimised delivery system that ensures deeper, more consistent plug formation across a larger number of sweat ducts.

The plug naturally dissolves over time as skin cells turn over and the duct lining renews itself. In clinical-strength products, this dissolution takes approximately 72 hours under normal conditions — hence the protection window.

The plug also survives surface-level washing (showering, swimming) because it's formed inside the duct, not on the skin's surface. This is why you can shower in the morning and still have protection from a product applied the night before.

The Triple Defense Approach

Mitchum's triple odor defense addresses the problem from three angles simultaneously:

1. Sweat reduction — Aluminium salts block sweat ducts, reducing the moisture that bacteria need to produce odour.
2. Antimicrobial action — Active ingredients reduce the population of odour-causing bacteria on the skin's surface.
3. Long-lasting fragrance — Encapsulated fragrance molecules release gradually over time, providing fresh scent throughout the protection window.

Is It Safe?

Aluminium-based antiperspirants have been used for over a century and have been extensively studied. Major health organisations, including the American Cancer Society, have found no conclusive evidence linking aluminium antiperspirants to health risks. The aluminium absorbed through the skin is a fraction of what you consume daily through food and water.

That said, if you have sensitive skin, start with a standard-strength formula before moving to clinical-strength. Apply to clean, dry, unbroken skin, and discontinue use if irritation occurs.