hyperhidrosis

What Causes Bad Underarm Odor?

Shad Douglas

Shad Douglas

— 3 min read

Summary

Bad underarm odor is primarily caused by the interaction of sweat with naturally occurring skin bacteria, leading to the production of odoriferous compounds. The odor is intensified by factors such as genetics, diet, hormonal changes, and hygiene practices. Understanding the sources and mechanisms behind underarm odor helps guide effective prevention and treatment strategies.

The Science of Underarm Odor

Types of Sweat Glands

Humans have two main types of sweat glands: eccrine and apocrine. Eccrine glands are distributed over most of the body and primarily produce a watery, odorless sweat that helps regulate body temperature. In contrast, apocrine glands are concentrated in areas such as the underarms and groin. These glands produce a thicker, milky secretion rich in proteins and lipids, which are odorless when first secreted.

Bacterial Metabolism and Odor Formation

The characteristic odor arises when apocrine sweat is broken down by skin-resident bacteria, such as Corynebacterium and Staphylococcus species. These bacteria metabolize sweat components, releasing volatile organic compounds (VOCs) like 3-methyl-2-hexenoic acid and androstenone, which produce the familiar "body odor" scent.

Key Factors That Influence Underarm Odor

Genetics

Some individuals naturally produce more or different types of sweat and sebum or have a distinct skin microbiome, making them more prone to strong underarm odor. Genetic variations in the ABCC11 gene, for example, directly affect the composition of apocrine secretion.

Hormonal Changes

Puberty, menstruation, pregnancy, and menopause can all increase sweating and alter sweat composition, leading to changes in body odor.

Diet and Lifestyle

Consumption of certain foods (onions, garlic, spices), caffeine, and alcohol can intensify underarm odor. Poor hygiene, tight clothing, and stress can also contribute.

Prevention and Treatment Options

Hygiene Practices

Daily washing of the underarms with soap reduces bacterial load and is a primary intervention. Wearing clean, breathable clothing helps minimize odor buildup.

Antiperspirants and Deodorants

Antiperspirants reduce the amount of sweat reaching the skin surface, typically using aluminum-based compounds, while deodorants mask or neutralize odor.

Clinical-Strength, At-Home Solutions: Drimedex

For individuals with excessive underarm sweating (hyperhidrosis) and persistent odor, Drimedex offers a clinical-strength, non-prescription antiperspirant specifically formulated to deliver maximum sweat protection without a doctor’s visit. Drimedex contains 15% Aluminum Chloride—the most effective FDA-monographed active ingredient for reducing underarm sweat—combined with a dermatologist-inspired, simplified formulation. This base includes purified water, glycerin (for hydration), hydroxyethylcellulose (for smooth roll-on application), potassium hydroxide (pH stabilization), and optional aloe vera (for added skin comfort).

Drimedex is designed to be gentler for sensitive skin than traditional prescription products (such as Drysol), but still delivers the highest level of non-prescription sweat control. As an easy-to-apply roll-on, Drimedex is an effective, accessible, and affordable alternative to costly prescription-only treatments. It can be conveniently purchased online without the need for a doctor’s appointment.

Prescription Treatments

For severe cases unresponsive to over-the-counter products, healthcare providers may recommend prescription antiperspirants containing higher concentrations of aluminum chloride, oral medications, botulinum toxin (Botox) injections, or even surgical interventions in rare circumstances.

When to See a Doctor

If underarm odor is persistent, worsening, or associated with new symptoms (such as skin changes or swelling), consult a healthcare professional to rule out medical conditions like infections, metabolic disorders, or hormonal imbalances.

References

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