We're developing our first compression sock, and before anything goes into production, we have to answer one big question: what should it be made of?
The factory gave us three options: a bamboo charcoal yarn, a merino wool blend, and an organic cotton blend. Each has real strengths, and each comes with trade-offs. Since sustainability is at the heart of everything we make, we wanted to share how we've weighed them up, and which way we're leaning.
First, Why Every Option Needs Synthetic Fibres
A compression sock has to stretch, hug your leg firmly, and spring back wear after wear. Natural fibres can't do that on their own, so every option on our list includes nylon and elastane (also known as Lycra or spandex). A compression sock will always contain more of these than our everyday socks. The real question is what makes up the rest.
Option 1: Bamboo Charcoal
Bamboo charcoal yarn is made by baking bamboo in a kiln at around 800°C until it becomes charcoal, grinding it into an ultra-fine powder, and blending that powder into a fibre as it's spun. The fibre carrying the charcoal in the option we were offered appears to be a type of viscose, and we're sending samples to a lab to confirm exactly what's in it.
- Pro: odour control. Charcoal is porous, which is why it's used in filters. In fibre form it's designed to help trap odour and limit the bacteria that cause it.
- Pro: moisture management. The fibre pulls moisture away from the skin and dries quickly, which matters in a sock you might wear all day.
- Con: the viscose that carries it. The charcoal itself isn't the problem. In the version we were offered, the charcoal powder appears to be blended into viscose (also called rayon), a fibre made by dissolving plant pulp with chemicals. The Competition Bureau of Canada has warned that making viscose uses a lot of chemicals that can harm the environment. It's the same process behind the "bamboo fabric" regulators have cautioned shoppers about, and it's hard to square with our values.
- Con: big claims we can't back up. Bamboo charcoal is often sold with promises of far-infrared rays that boost circulation, "negative ions" and full biodegradability. We haven't seen independent evidence that convinces us.
Option 2: Merino Wool Blend
Merino wool naturally does a lot of what bamboo charcoal promises: it wicks moisture, resists odour, and keeps feet comfortable in both warm and cool weather. On paper, it's a strong choice.
- Pro: natural performance. Moisture-wicking and odour resistance come from the fibre itself, with no added treatments.
- Con: not much merino in the mix. The blend we were offered is 22.5% merino, 22.5% acrylic, 44% nylon and 10% Lycra. With less than a quarter merino, and the same amount of acrylic, a fully synthetic fibre, we'd be selling a "merino" sock that's mostly synthetic. For comparison, our Dash Ankle socks are 66% merino wool. That didn't feel honest.
Option 3: Organic Cotton Blend
This option uses organic cotton as the base yarn, with nylon and elastane for compression and stretch. It's the same organic cotton our customers already know from the rest of our range.
- Pro: our core natural fibre. Organic cotton is grown without synthetic pesticides or fertilisers, and it's soft and breathable against the skin.
- Pro: no chemically processed base fibre. No viscose, and no question marks about where the yarn comes from.
- Con: less moisture-wicking. Cotton holds on to moisture more than merino or charcoal fibres, and it doesn't have their built-in odour resistance.
- Con: more nylon than our other socks. To reach proper compression, this sock needs a significantly higher share of nylon than our everyday styles. We think that's justified by what the sock has to do.
Where We've Landed (For Now)
We're leaning towards the organic cotton version. It means giving up some of the moisture-wicking and odour control that bamboo charcoal offers, but it keeps the sock built on a natural fibre we trust, without the environmental cost of viscose or a "merino" label that's mostly synthetic.
Nothing is final yet. The next step is testing samples on real feet, and we'll share what we decide.
Final Thoughts
"Bamboo" on a label doesn't automatically mean sustainable, and "merino" doesn't always mean mostly wool. Whatever you're buying, it's worth asking what the fibre is actually made of and what the claims are based on. We'd rather answer those questions up front, including for our own socks.
Shopping for High Quality Socks?
We produce a range of high-quality socks made with premium, eco-friendly yarns such as organic combed cotton and merino wool. They incorporate all of the design features recommended most by podiatrists, and most styles are offered in 3 sizes to fit most adults. Learn more here:
Sources:
- Competition Bureau Canada – "Don't be bamboozled: the real deal with 'bamboo fabric'" (2019)
- ECI Group – "The Science and Sustainability of Bamboo Charcoal Yarn" (2025)
- Paiho – "Charcoal Tech" bamboo charcoal fibre product brochure
