At first, Theory founder Andrew Rosen only focused on finding the perfect fit – first for women and then for both sexes – by developing an innovative stretch fabric. But along the way, he got interested in sustainability as well. Leading up to the brand’s twentieth birthday, for instance, he introduced ‘Good Wool’, Theory’s most sustainable collection to date. It is made from premium merino wool sourced from free-roaming Australian sheep (wool the brand got straight from the source, by the way, to ensure traceability). The lining of Good Wool garments is biodegradable, while the buttons are made from corozo nuts.

The Italian mill that turns the wool into fabric has been in the same family for four generations and uses hydro turbines and solar panels to produce its own electricity. Talk about energy efficiency! In addition, the mill has its own water treatment plant to make sure the dyes they use won’t harm the environment.

Finally, the label collects used Theory clothes on behalf of Year UP, a non-profit organisation creating professional opportunities for young adults. Customers who donate clothes get a discount on their next purchase.