Bamboo viscose is a very soft and breathable textile. There are many types of viscose fabric and from what I have gathered the last few weeks the most eco-friendly and breathable seems to be bamboo viscose and lyocell viscose (usually made from eucalyptus).

There’s a lot of uncertainty around the eco-friendliness of the production of bamboo viscose, but from I can gather it’s a lot better than most cottons and a lot better than polyester (both for the environment and for our skin).

I could go on forever about the different fabrics, but to keep it short if you want soft and breathable underwear go for either bamboo viscose or lyocell viscose.

(Source: am fat guy)

Not sure where your are, but there’s a brand called Boody here in Australia. They might ship.