“Going commando” refers to the practice of not wearing underwear beneath outer garments. This choice can increase body odor, though the outcome depends on an individual’s activity level and specific anatomy. Body odor, or bromhidrosis, does not originate from sweat itself. The smell is created when natural skin bacteria interact with and metabolize certain components within sweat secretions. Understanding this biological process helps determine the odor risk associated with skipping undergarments.
The Science of Odor Production
The human body possesses two primary types of sweat glands. Eccrine glands are distributed across the entire body and release a watery, mostly odorless fluid for thermoregulation. Apocrine glands are concentrated in areas like the armpits and the anogenital region, becoming fully active after puberty. These glands release a thicker, milky fluid rich in proteins, lipids, and fatty acids.
This apocrine secretion, while odorless when first released, provides an ideal nutrient source for resident skin bacteria. Specific microorganisms, particularly those from the Corynebacterium and Staphylococcus species, thrive by breaking down these fatty components. This metabolic process releases volatile organic compounds (VOCs) that possess the characteristic strong smell associated with body odor.
One well-studied VOC is 3-methyl-2-hexenoic acid (3M2H), a compound often described as having a pungent odor. The concentration of these odor-causing compounds is directly linked to the amount of apocrine sweat available and the density of the bacterial populations present on the skin. The environment created by moisture and warmth in the groin area naturally promotes this odor-producing bacterial activity.
How Fabric Manages Moisture and Bacteria
The absence of underwear directly impacts the local microenvironment, increasing the likelihood of odor production. Underwear, especially when made from natural, breathable fibers like cotton, functions as a wicking agent. This layer absorbs moisture from sweat and other natural secretions, drawing it away from the skin surface.
When this fabric barrier is removed, the moisture is trapped between the skin folds and the rougher material of outer clothing. This moisture retention is the greatest driver of bacterial overgrowth, creating the optimal warm and humid environment that odor-causing microbes prefer. The longer the skin stays damp, the more time bacteria have to metabolize secretions and generate VOCs.
While going commando can theoretically increase air circulation, this potential ventilation is often outweighed by poor moisture control. During physical activity, sweat production accelerates, leading to saturated skin and clothing almost immediately. The outer garment then becomes the primary absorber of bacteria and moisture, requiring more frequent washing to prevent odor accumulation.
Anatomical Differences and Odor Risk
The risk profile for increased odor when forgoing underwear is distinct for different anatomies, largely due to variations in moisture retention and natural secretions.
Individuals with a Vulva
For individuals with a vulva, natural vaginal discharge and the close proximity of the urethral and anal openings contribute to a consistently moist environment. The lack of a moisture-wicking layer allows these secretions to pool against the skin and outer garment, which can intensify natural odors.
This pooling increases the overall humidity level, providing a better environment for the growth of odor-causing bacteria. Furthermore, the lack of a barrier means that bacteria from the gastrointestinal tract, which are strong odor producers, can more easily migrate from the anal region to the genital area.
Individuals with a Penis and Scrotum
For individuals with a penis and scrotum, the primary odor risk relates to heat regulation and friction. The scrotum is naturally prone to producing sweat to maintain an optimal temperature. When the supportive layer of underwear is removed, the skin of the scrotum and inner thigh can rub directly against the outer garment or against each other, increasing friction.
This increased friction stimulates local apocrine glands to secrete more sweat, heightening the availability of the fatty acids and proteins that bacteria metabolize. The lack of support also causes the penis and scrotum to press against the thigh, maximizing skin-on-skin contact and trapping moisture and heat.