The key to using clothing to prevent or lessen body odor lies in the fabric's ability to release sweat quickly -- before bacteria can begin to feast on it. There are natural and man-made fabrics that expertly wick moisture away from the skin and to the edge of the material where it evaporates. Other fabrics, however, will trap moisture in the fabric and on the skin, and make body odor worse.
A fabric's ability to transmit and release moisture is known as breathability, which is the common term for the moisture vapor transmission rate (MVTR). The MVTR is measured by calculating how many grams of moisture move through a square meter of fabric in 24 hours. Generally, the greater the MVTR, the less likely the fabric will absorb and retain odor-causing moisture [source: Commercial Sewing].
You may be thinking, "Great! Now all I have to do is find clothing labeled 'breathable' and BO will be a problem of the past." Not so fast. There's not an industry standard regarding breathability. Nearly any label can carry the term, usually preceded by words like "ultra" or "extremely." This means you'll need to arm yourself with information about fabrics, rather than relying on label hype as a guide.
Natural fabrics -- created from the fibers of animals, bugs or plants -- are a good place to start. You'll want to steer clear of 100 percent cotton fabrics, because they take a long time to dry and will allow body odor to bloom in the meantime. This is largely because 100 percent cotton fabrics are composed of fibers that swell with moisture and thereby reduce the pores of the fabric [source: Das and Kothari].However, other natural fabrics absorb and release sweat quickly, including hemp, a fabric woven from the stem fibers of the Cannabis sativa plant, and linen, woven from flax stems [source: Shop Well With You].
While it sounds counterintuitive to wear wool to prevent body odor, this natural fiber is an excellent choice. Wool can absorb up to 36 percent of its weight in moisture (this includes sweat!) without feeling wet and will dry quickly. Wool also releases minute amounts of body heat as it absorbs moisture, so it will help keep you cool. Plus, wool is naturally antibacterial, which means you can wear it, sweat in it and keep wearing it (sometimes for consecutive days) without reeking of BO. Merino wool has very fine fibers which makes it an excellent fabric for base layers [source: REI].