Why Do Humans Sweat Smells Different?

Humans have two main types of sweat glands. Most of your body is covered in eccrine glands that make watery sweat to cool you down like a fan. But under your arms and in your groin, you have apocrine glands. These are bigger and make a thicker, milky fluid.

This milky fluid doesn't smell bad right away. It is odorless when it sits on your skin. However, tiny microbes called bacteria live all over our skin. When the sweat from apocrine glands mixes with these bacteria, they eat the proteins and fats in the sweat.

As the bacteria eat, they release waste products that have strong smells. Since everyone has slightly different bacteria living on their skin, your smell is unique! It is like a fingerprint made of smells.