Myth, bamboo always shrinks

Sep 12, 2026

Short answer: Pre-shrunk bamboo viscose shrinks one to two percent in the first wash and hardly at all after that. If it shrinks more, the wash was too hot or the dryer was set to high heat.

Where the myth comes from

Many people have seen a jumper come out of the machine smaller than it went in. That memory sticks and easily becomes a rule about the whole material. But shrinkage mostly depends on how the fabric was treated before sewing and how it is washed afterwards. The material itself is only part of the story.

Pre-shrinking does most of the work

The fabric is treated with heat and moisture before it is sewn, so the shrinking has already happened. The garment has its final measurements before it reaches you. The small remainder shows up in the first wash and then stops. See bamboo boxers, which are washed often and need to keep their size.

Heat is what shrinks it

Washing above sixty degrees and tumble drying on high heat pull the fibres together again. It is the same process as pre-shrinking, only without control. Stick to forty degrees and low heat when drying. This matters for bamboo t-shirts for men too, where length makes a big difference to the fit.

One to two percent goes unnoticed

On a jumper that is seventy centimetres long, two percent is just under one and a half centimetres. That is so little that most people never notice, especially as soft fabric gives a little with wear. Length and width feel the same. With bamboo socks, a change that small cannot be felt at all.

The first wash

The first wash matters most. Wash at forty degrees, ideally on a gentle cycle, and hang the clothes to dry. Ease them into shape while damp so the seams sit straight. Once that is done, the fabric has taken its last small shrink, and the measurements barely change after that, even over many washes.

Drying without heat

The tumble dryer is the most common reason clothes shrink more than expected. Heat combined with movement pulls the fibres together faster than anything else. Hang your clothes on a hanger or a drying rack instead. If that is not possible, choose the lowest heat and take them out while slightly damp.

How to choose your size

Choose the size that fits you today. Pre-shrunk fabric keeps its measurements, and a size up will simply end up too loose. If you are unsure between two sizes, check the size chart and measure a garment you already like. That gives a more accurate answer than guessing at shrinkage.

When it has shrunk anyway

Once a garment has shrunk from high heat, the damage can rarely be fully undone. You can soak it in lukewarm water and gently ease it into shape while it dries flat. That helps a little, but the result is uncertain. The best approach is to avoid the heat from the start.