Fashion brand Theory has launched its Low-Carbon Regal Wool collection following a methane reduction pilot conducted with its long-term wool supplier, Congi Farm in New South Wales, Australia. The Responsible Wool Standard (RWS)-certified and fully traceable collection is made from fine Merino wool with a micron size close to cashmere, the garments offer a soft and premium feel.

The project used Asparagopsis, a naturally occurring red seaweed known to reduce methane production during digestion when added in small quantities to livestock feed. Sea Forest supplied the seaweed-based feed supplement, SeaFeed, which was provided to 2,000 Merino sheep through specially designed lick blocks.

According to Gonzalo Pertile, Vice President of Sustainability at Theory, the seaweed made up only one percent of the sheep's diet but resulted in a measured 43 percent reduction in enteric methane emissions. During the trial period, this reduced greenhouse gas emissions by approximately 54.5 metric tonnes of carbon dioxide equivalent (CO₂e), an amount comparable to the annual emissions produced by around 12 petrol-powered passenger vehicles.

Following the success of the first trial, Theory has expanded the programme. The second phase increased the scale from 2,000 sheep on one farm to 10,000 sheep across four farms in Australia, while also testing different feeding methods and trial durations. The second pilot has now been completed, and the results are currently being independently evaluated.