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Is there a plastic-free future for your leggings?

Activewear relies on synthetics. But as innovators bring stretch denim alternatives to market, important learnings for the sportswear sector could surface.
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Photo: Dimensions/Getty Images

With denim production notoriously resource-intensive, it might seem counterintuitive to think the blue jean could be a solution to one of sportswear’s biggest sustainability problems: the over-reliance on stretch fabrics made from plastic. And yet, a spate of innovations this year is led by collaborations with denim brands that could help pave the way for plant-based activewear that actually performs.

Despite only accounting for 1.1 per cent of global fibre production, elastane (also known as spandex) is found in up to 80 per cent of clothing, according to materials science company Yulex, and is often blended with other materials to provide stretch and durability. The sportswear market depends on this fossil-fuel derived fibre to create performance products including leggings, sports bras and cycling shorts.

“Synthetic stretch fabrics enable comfort, performance and longevity,” says Natascha Radclyffe-Thomas, professor of marketing and sustainable fashion at Ravensbourne University in London. “In fashion — not just in sportswear — they’ve become pervasive. People expect a certain level of comfort from their clothes and have become interested in high-performance garments even if they’re not actually being active. We also now tend to associate function with synthetics.”

Elastane is not only derived from fossil fuels and energy-intensive to produce, it is also non-biodegradable and contributes to microplastic pollution. However, while there are bio-derived alternatives, barriers remain to their use. “Mainly cost and infrastructure,” says Radclyffe-Thomas. Could the denim industry help to unlock progress?

The complexities of bio-based stretch

A growing number of denim brands are making the most of the existing innovations to take elastane-free products to market. But it’s not necessarily a lift-and-shift solution for performance wear. For example, LA-based denim brand Triarchy has found a way to make its jeans 100 per cent plant-based by replacing synthetic stretch with Coreva, a plastic-free, biodegradable and compostable stretch denim made from natural rubber from the hevea brasiliensis tree and developed with Italian manufacturer Candiani Denim.

LA-based denim brand Triarchy has found a way to make its jeans 100 per cent plant-based by replacing synthetic stretch with Coreva, a plastic-free, biodegradable and compostable stretch denim made from natural rubber.

Photo: Adam Taubenfligel for Triarchy

This cannot simply be replicated for sportswear, however. “Right now, Coreva pairs best with denim because of its structure and fibre compatibility,” says Triarchy co-founder Adam Taubenfligel. “Sportswear typically demands thinner, high-mobility fabrics, which currently aren’t optimal for Coreva’s needs. But five years ago, plastic-free stretch denim sounded like science fiction, and now I’m wearing it. So never say never.”

Once Triarchy’s North America exclusivity for the Coreva technology ends in 2026, Taubenfligel plans to broaden access to it, helping to build better infrastructure and reduce costs. “Investing in progress always comes before scaling accessibility,” he says. “As with any new technology, Coreva currently comes at a premium.”

Yulex’s natural alternative to neoprene has been adopted by Patagonia and Finisterre for wetsuits. Like Coreva, Yulex has created its own 100 per cent bio-based alternative to synthetic stretch from hevea brasiliensis rubber. Yulex CEO Liz Bui says Yulastic has the potential to replace up to 300,000 metric tonnes of spandex per year, initially in denim, socks and intimate apparel, which encompasses about 25 to 30 per cent of the elastics market. The company says a number of well-known brands are already on board, due to launch capsule collections.

Now, Yulex is also developing a finer denier Yulastic fibre for leggings as well as other sportswear and athleisure products, with an expected launch in 2026. “Finer denier filaments and fibres produced from natural rubber are more challenging to develop because the technology is different from the current process,” says Bui, adding that the finer fibre will also incorporate new plant-based polymer formulations. “Yulex has intellectual property and a proof of concept for the finer denier filaments, but we are seeking strategic partners to help us scale up pilot production quantities and beyond.”

The rubber tree plantations and processing plant where tree latex gets processed into Yulex Prime or Yulex Pure latex, the raw material used for Yulastic.

Photo: Courtesy of Yulex

A like-for-like synthetic alternative to performance stretch is not yet available for an end product, says Claire Weiss, head of innovation at Future Fabrics Expo. “I think what we’ll see in the next couple of years is more likely to be on a par,” she says. “I think we’re also in that transition moment with these materials, where we may have a bio-based input for one part, but still need a petrochemical finishing. And that’s a huge part of the problem: where do you draw the line on performance? It’s normally up to the brand or the innovator to decide where that line is drawn and be transparent about it by showing what they’re working towards.”

Cost vs demand dynamics

Premium denim brand Agolde, also based in LA, has partnered with The Lycra Company to launch a Spring/Summer 2025 collection featuring Lycra’s bio-derived EcoMade fibre. Trialled at the end of 2024 ahead of full-scale production later this year, the fibre uses dent corn — an industrial field corn — as feedstock; the corn is converted into glucose syrup and fermented to create a key component.

Some 30 per cent of Lycra EcoMade is still derived from petroleum. Lycra communications director Karie Ford explains that, in the production of spandex, there are two main ingredients: PTMEG (which gives spandex its stretch) and MDI (which contributes to its recovery power). In Lycra EcoMade, PTMEG, which accounts for 70 per cent, is bio-based, while the MDI portion comes from petroleum-based feedstock. The remaining 10 per cent is derived from a mixture of petroleum and minerals, with Lycra working on separate solutions for these finishes and additives.

“The technology to produce MDI from a bio-derived feedstock — at substantial cost — has been developed,” says Ford. “But the cost versus demand dynamics are such that no companies have yet been willing to invest in a dedicated bio-derived MDI facility. Today, the best we can get is an MDI produced from a blend of bio-derived and petroleum-derived feedstocks. We anticipate this dynamic to change in the future as the cost-demand balance shifts.”

Lycra EcoMade already commands a premium, says Amy Williams, CEO of The Citizens of Humanity Group, Agolde’s parent company. Agolde hasn’t passed on any cost to the end consumer. “Our other investments in regenerative cotton and Eco-Indigo were significant, and we absorbed those costs. Over time, we expect [the costs] to go down, as more demand is demonstrated, and more brands and mills move to these solutions. Some early innovations are extremely expensive. Supplies can be limited, so you need to transition part, but not all, of your supply chain,” she explains.

Based on the initial availability, Agolde will produce approximately 75,000 pairs of jeans this year — the equivalent of 10 per cent of Agolde’s stretch business — with plans to ramp up production for 2026. The brand is in negotiations with Turkish denim mill Orta to move all stretch production to the new fibre. “The team at Orta was extremely proactive in being an early adopter of this product, as they have been with regenerative cotton and our Eco-Indigo,” says Williams.

Orta had spent six months testing and trialling the concept, after Lycra approached the mill. Orta sales and marketing director Oktay Okuroglu says that, in most cases, innovators approach the mill or manufacturer first, as modifications and process changes are commonplace in new fibre production. “Once we had achieved the same result in performance and quality as [synthetic] lycra, I approached Amy,” he explains.

The mill’s partnership with Agolde and French dye company Pili on a bio-based indigo dye was a two-year project, and more complicated than the Lycra fibre. For that collaboration, it was Agolde who approached Orta for further R&D. “The first result was terrible,” Okuroglu notes. “The shade wasn’t right, but everyone persevered.”

The role of brands

For Yulex’s Bui, overcoming challenges of cost, availability and scale comes down to a single action from brands. “Invest!” she urges. “Brands want innovation, but few invest to help innovations succeed, scale and commercialise. Innovators take most or all the risk.”

Amanda Johnston, curator at Future Fabrics Expo, agrees that the only way innovators and early-stage developers can scale their elastane-free solutions is through collaboration across the supply chain, specifically with brands. “Two-thirds of global fibre demand is still made from petrochemicals,” she says. “Even though there has been some take-up of recycled fibres by the industry, we’re still not seeing anywhere near enough of that — and they’re the lowest hanging fruit. We’re still stuck in the fast fashion model, a race to the bottom where the cheapest material wins. There isn’t a level playing field for those producers doing things the right way.”

For SS26, sportswear brand Under Armour will debut Neolast, a stretch fibre made from a type of recyclable thermoplastic and developed in collaboration with US tech and chemical company Celanese. But Eric Liedtke, executive VP of brand strategy at Under Armour, wants to take the stretch innovation further. “We haven’t figured out how to do that high-stretch, rebound compression [for performance wear] from a plant-based solution yet, but there are innovation pipelines. In two years, I hope to have an innovation in my hand that we can start planning to go to market with in a meaningful way,” he says.

In April, the brand launched a limited-edition capsule collection with sustainability collective Unless, comprising hoodies, T-shirts and shorts, which it claims are 100 per cent plant-based and compostable. “You’ve got to send out a statement of intent, build awareness and an audience, and then start to scale — because it can’t always be a premium proposition,” says Liedtke. “Consumers shouldn’t have to sacrifice their taste for their values, nor their values for their taste. So we have to give them something that’s at the same level, quality, durability, performance and aesthetic at the same price.”

ZymoChem is a biotech company that announced a multi-year collaboration with Lululemon in March to develop an alternative to nylon 6.6 — one of the most commonly used nylons in terms of volume.

Photo: ZymoChem

It’s a sentiment shared by Harshal Chokhawala, co-founder and CEO of ZymoChem, a biotech company that announced a multi-year collaboration with Lululemon in March to develop an alternative to nylon 6.6 — one of the most commonly used nylons in terms of volume, and a foundational material used in performance products, including Lululemon’s cult Align and Wunder Train leggings.

ZymoChem’s technology replaces a key building block of nylon 6.6 — adipic acid — with a bio-based version, using corn as feedstock. Traditional adipic acid production releases nitrous oxide, a greenhouse gas that is currently the most significant ozone-depleting substance being emitted, according to the UN Environment Programme.

“Success in this space requires thinking about scale from day one. Brands need to commit to multi-year development partnerships that allow for iterative improvement and gradual scaling,” says Chokhawala. “They also need to engage their entire supply chain early in the process, ensuring that each stakeholder understands how to work with these new materials.”

The overarching message? The sportswear industry could be on the brink of a petroleum-free future — but only if everyone in the value chain comes together to play their part.

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