What happens in a fibre that holds moisture

Short answer: A fibre that absorbs water pulls the moisture into itself. The surface becomes drier, and the bacteria on the surface get worse conditions than in a fabric where the water stays outside. That delays the smell, but it does not remove the cause.

The water is moved away from the surface

In viscose, water is bound between the cellulose chains inside the fibre. The surface can therefore feel dry even though the fabric holds a lot of moisture. That is a property of how the fibre is built. The difference is felt most on the skin, where moisture would otherwise stay between skin and fabric.

The bacteria live on the surface

Most bacteria sit on the outside of the fibre, not inside it. If the surface is dry, they work more slowly. The moisture is still in the fabric, but it is not in contact with the place where the bacteria sit. See bamboo footies for men if you wear short socks in shoes.

This is not the same as antibacterial

The fibre kills nothing. It only moves the moisture, and that delays the smell instead of removing the cause. So it is more honest to say a fabric makes it harder for odour to develop than to claim it does not smell. See Turiform and bamboo compression stockings.

What happens when the fibre is saturated

A fibre can only take up a certain amount of water. Once it is saturated, the moisture stays on the surface as in other fabrics, and the bacteria get better conditions again. That is why time and drying still matter, even for fabrics that handle moisture well.

Drying time is part of the explanation

A fabric that has taken up a lot of moisture must also release it again. That can take longer than for a fabric that is only damp on the surface. Hang the clothing so air can reach it, and let it dry fully before you wear it again or put it in the wardrobe.

Why cotton is similar

Cotton is also cellulose and also takes moisture into the fibre. So it behaves in many ways like viscose when it comes to moisture and smell. Differences in the build and thickness of the fabric still affect how it feels and how fast it dries, so compare clothing made for the same use.

The comparison with synthetic fibres

Synthetic fibres such as polyester do not take water into the fibre, so the moisture stays on the surface together with skin oil. The bacteria find moisture and food side by side. That is one reason synthetic clothing can start to smell faster, and often needs a warmer wash to release the oil.

What this means in daily life

In daily life it means that a fabric that handles moisture well can give you more time between washes, but it does not do away with washing. On a long day, an extra pair of socks in the bag can help more than anything. Most important is that clothing dries fully between uses.

Washing and care still apply

Whatever the fibre, clothing worn close to the skin must be washed and dried fully. A wash removes food and bacteria, while the fibre's ability to move moisture only helps along the way. Follow the label, use no more detergent than needed and change clothes after sweaty days.

Frequently asked questions

Does this mean bamboo viscose never smells

No. It takes longer, but the smell comes there too. The fibre takes moisture into itself but cannot stop bacteria, so the clothing still has to be washed and dried.

Why does cotton smell less than polyester

For the same reason. The water goes into the fibre instead of staying outside. Bacteria then find worse conditions, and skin oil does not bind as strongly to the fibre.