Why Do My Armpits Smell Sour? Causes & Body Odor Guide

Why Do My Armpits Smell Sour?

Sweat itself is generally odorless. Underarm odor, including a sour smell, is typically caused by the interaction between your sweat and the natural bacteria living on your skin.

Primary Causes of Sour Underarm Odor

  • Apocrine Sweat Glands: Apocrine glands are located mainly in areas dense with hair follicles, such as your armpits and groin, secreting a protein-rich fluid that bacteria break down to produce sharp or sour body odors.
  • Bacterial Breakdown: Certain strains of bacteria on the skin feed on lipids and proteins found in apocrine sweat, producing metabolic byproducts that smell sour, tangy, or pungent.
  • Diet and Foods: Consuming foods like garlic, onions, cruciferous vegetables, and spicy foods releases sulfur compounds and metabolites through sweat, altering body odor.
  • Hormonal Fluctuations: Shifts in hormone levels due to stress, anxiety, puberty, or other physiological changes can stimulate apocrine glands to produce more sweat, intensifying odor.
  • Clothing Fabrics: Synthetic materials like polyester, nylon, and acrylic trap moisture and heat against the skin, creating an ideal breeding ground for odor-causing bacteria compared to natural fibers.