What is body odor?
Body odor, or B.O. as it is commonly referred to, is a conglomeration of odors from the body’s surface and cavities. In most instances, body odor is thought of as the general odor a person has without using any fragrant scents to mask the natural smell of the skin. It may not be offensive in nature and is sometimes described as pleasant. However, body odor or B.O. is often used as a general term to describe bad body odor.
However, odor from the mouth, vagina and even odoriferous discharges from the body, like in ear discharge, can also be considered as body odor because it contributes to the overall odor from a person.
What causes body odor?
The skin is naturally odorless. However, perspiration, dust, dirt and topical applications may all contribute to skin odor. Sweat is probably the most prominent contributor because even after bathing and removing other substances from the skin, sweat will return, especially with activity, emotional stress or in hot and humid environments.
The body has two types of sweat glands :
- Eccrine glands which are present throughout the body
- Apocrine glands which are found in areas that have hair (scalp, groin, armpits)
Sweat from the eccrine glands plays an important role in thermoregulation (cooling down the body in hot environments). Eccrine sweat is composed of water, sodium, potassium lactate, urea, ammonia, serine, ornithine, citrulline, aspartic acid, heavy metals, organic compounds, and proteolytic enzymes. High temperatures and physical activity are known to increase eccrine sweat throughout the body.
Sweat from the apocrine gland is more viscid due to fatty substances within it. The exact function of apocrine sweat is unknown and it is thought to assist with hair texture and may also be a scent gland. Apocrine sweat becomes more prominent from the time of puberty as the secondary sexual characteristics begin to develop. It is secreted in smaller quantities than eccrine sweat and is associated with emotions and hormonal changes.
Offensive Smelling Sweat
Sweat, both eccrine and apocrine, does have an odor but it is usually not an offensive odor. It is when the bacteria on the skin consume the substances in the sweat that is on the skin surface that a stronger or foul odor may become noticeable. Body odor is more prominent on the warm, covered areas of the body where the bacteria can thrive. Hygiene plays a crucial role in limiting or preventing a bad body odor.
Excessive perspiration (hyperhidrosis) will increase the chances of a foul body odor, especially if it is chronic in nature. An offensive odor associated with sweating is known as bromhidrosis. At other times, a bad body odor may bre related to medical conditions like in :
- diabetes or starvation where fat break down causes the release of acetone resulting in a sweet or fruity odor
- liver failure where the compound methyl mercaptan causes a musty or mousy odor
- kidney failure where the build up of urea in the body (uremia) results in an ammonia or fishy odor
These causes are discussed further under Bad Body Odor.
Article reviewed by Dr. Greg. Last updated on October 23, 2010