Not all wool is the same. The gap between a scratchy jumper that lives at the back of the wardrobe and a merino t-shirt you wear three times a week comes down to a single number measured in millionths of a metre. Here is what that number means, why it matters, and what you should be looking for when you buy.
What is a micron, and why does it determine everything?
A micron is one millionth of a metre, the unit used to measure the diameter of a single wool fibre. The lower the micron count, the finer and softer the fibre. A human hair measures between 50 and 100 microns. Standard lambswool runs from 25 to 35 microns. Merino wool ranges from 15 to 24 microns depending on grade.
The reason micron count matters so much comes down to physics. Fine fibres bend easily when they press against skin. Coarse fibres don't bend, they poke. Textile science research has consistently identified 22 microns as the approximate itch threshold: fibres above this diameter are stiff enough to stimulate pain receptors in the skin, producing that familiar scratchy sensation. Below 22 microns, fibres flex sideways on contact rather than poking, which is why superfine merino feels soft rather than prickly even worn directly against the skin.
What most people dismiss as a wool allergy is almost always a reaction to fibre diameter, not wool itself. The Woolmark Company, drawing on over a century of published research, concluded there is no credible evidence that wool is an allergen. What causes discomfort is coarse fibre, and superfine merino eliminates that problem.
What is superfine merino wool, and how does it compare to other grades?
The wool industry classifies merino by fibre diameter into a hierarchy of grades.
Ultrafine merino sits below 16.5 microns. Extraordinarily rare, used in the most delicate luxury garments and some medical-grade textiles for eczema sufferers.
Superfine merino spans roughly 16.5 to 18.5 microns. Exceptionally soft, suitable for next-to-skin garments, and the grade used in high-end fashion and performance wear. This is what Citizen Wolf uses: 17.5 micron superfine merino, sourced from RWS certified Australian farms.
Fine merino runs from 18.5 to 21 microns. Still soft and below the itch threshold for most people, used widely in quality knitwear.
Medium merino sits between 21 and 22.5 microns. Borderline for sensitive skin. People who tried a "merino" product and found it scratchy were likely wearing this grade.
Broad and strong merino covers 22.5 microns and above. Crosses the itch threshold for most people, better suited to outerwear and heavy knitwear than anything worn next to skin.
A single micron of difference is meaningful. Research cited by textile scientists notes that a one-micron reduction in fibre diameter can increase perceived softness by 15 to 20 percent. The distance between a 22-micron "merino" and a 17.5-micron superfine merino is not subtle. It is the difference between a garment you tolerate and one you reach for every time.
Why is Australian merino considered the world's best?
Geography, genetics, and generations of breeding specialisation.
Australia's climate, particularly the inland tablelands of New South Wales, produces conditions uniquely suited to growing fine fibre. Merino sheep raised in these regions develop the long staple length and consistent micron count that premium textile mills require. The Woolmark Company has documented that Australia produces approximately 80 to 90 percent of the world's superfine apparel wool, making it the single most important source in global supply.
That dominance is not accidental. Australian woolgrowers have spent decades selectively breeding for fibre fineness. The result is a raw material that Italian mills, Japanese knitters, and European fashion houses consider irreplaceable.
Supply is also under structural pressure. According to the Australian Wool Production Forecasting Committee, Australia's shorn sheep numbers are forecast to fall to 57.9 million head in 2025-26, a level not seen since 1904, driven by drought, rising farm costs, and land use shifts. When demand for a fibre is rising globally and supply is declining, the economics of quality become more compelling: the finest grades command prices that reflect genuine scarcity.
Our merino is sourced from an experienced Melbourne-based supplier who buys exclusively from Australian farms, with extra-long staple fibres selected for softness, strength, and resistance to pilling.
What does RWS certification actually guarantee?
The Responsible Wool Standard, administered by Textile Exchange, the global non-profit that develops sustainability benchmarks for the textile industry, is the most rigorous independent certification for wool sourcing.
RWS certification requires compliance across three areas. First, animal welfare: the standard prohibits mulesing outright, and mandates that sheep have access to clean water, adequate nutrition, shelter, and veterinary care. Painful procedures without anaesthesia are banned. Second, land management: certified farms must demonstrate progressive practices covering soil health, biodiversity, and water stewardship. Third, chain of custody: every site from farm through processing, spinning, dyeing, and manufacturing must be independently certified and audited annually. When a product carries the RWS label, the wool inside it can be traced back to specific certified farms, not claimed, traced.
Certification is not self-reported. Audits are conducted by accredited third-party bodies including Control Union, ICEA, and Ecocert. Non-compliance triggers corrective action requirements; repeated violations lead to decertification.
Global RWS-certified wool production grew 340 percent between 2018 and 2023, according to Textile Exchange, reflecting rising demand from brands and consumers who want verifiable claims rather than marketing language. That growth is meaningful, but the standard still covers a fraction of global wool production. Most wool sold today carries no independent certification of how the animals were treated or how the land was managed.
How does superfine merino compare to cashmere and synthetics?
Cashmere comes from the undercoat of cashmere goats and typically measures 14 to 16 microns, making it comparable to ultrafine merino in softness. But a merino sheep produces between 4 and 10 kilograms of wool per year; a cashmere goat produces 200 to 300 grams of usable fibre. That scarcity drives cashmere prices up, and it has driven significant environmental degradation in Mongolia and China, where overgrazing by cashmere goats has contributed to desertification. Merino wool, by contrast, is a renewable resource with a well-managed global supply chain, particularly at the certified end.
Against synthetics, merino wins on almost every dimension that matters for everyday wear. Polyester and nylon regulate temperature poorly, trap odour permanently, and shed microplastics with every wash, fibres that enter waterways and accumulate in marine ecosystems. According to research from the Plastic Soup Foundation, a single synthetic garment can shed more than 700,000 plastic microfibres in a single wash cycle.
Merino fibres biodegrade naturally. They absorb up to 30 percent of their own weight in moisture before feeling wet. They regulate body temperature across a wide range because the fibre structure traps air when cold and releases moisture when warm. And they resist odour naturally because the protein structure of wool binds to odour-causing compounds rather than letting them sit on the surface.
The case for superfine merino over synthetics is not primarily ethical, it's functional. It is simply a better material for clothing you wear next to skin.
Why does Citizen Wolf use 17.5 micron superfine merino?
Because it is the finest grade that makes sense for a t-shirt worn daily.
At 17.5 microns, our merino sits comfortably in the superfine classification, well below the itch threshold, soft enough to wear directly against skin without a layer underneath, and fine enough to drape rather than bulk. It is sourced exclusively from ewes' fleece, with no neck, belly, or crutchings included, because the uniformity of the staple affects the consistency of the finished fabric.
We make every merino garment to order in our Marrickville factory using the same Magic Fit® algorithm as our cotton range. Your exact measurements, your exact pattern, one piece at a time. No inventory. No standard sizes.
The result is a garment that combines the world's finest natural fibre with the fit that makes it worth wearing every single day. The every day weight makes it perfect to wear on its own, or as a base layer in winter. That is the only metric that matters for cost per wear, which is the only metric that matters for value.
Explore Citizen Wolf superfine merino, custom-fit to your body and made in Sydney.
Shop Women's Merino | Shop Men's Merino
Posted: 15 June 2026