Recycled nylon vs virgin nylon, on the numbers

Recycled nylon is better than virgin nylon, and the gap is smaller than the marketing suggests. Both numbers matter — the size of the win, and the size of the remaining problem.

The activewear category leaned on recycled nylon as a sustainability headline for most of the last decade. The lean is fair. It is also not a finish line. Here is the math, with the citations, with the caveats. The wider context is in what sustainable activewear actually has to mean.

What virgin nylon costs

Virgin nylon 6.6 is produced from petrochemical feedstocks — adipic acid and hexamethylenediamine. Adipic acid production is the larger emissions story: it releases nitrous oxide (N₂O), a greenhouse gas with a global warming potential roughly 273 times that of CO₂ over a 100-year horizon (IPCC AR6, 2021).

Industry life-cycle assessments place cradle-to-gate emissions for virgin nylon 6.6 at roughly 7–9 kg CO₂e per kg of fibre, depending on the facility and abatement technology installed (PlasticsEurope EcoProfile, 2014, Polyamide 6.6). Modern adipic-acid plants with N₂O abatement run at the lower end; older Asian capacity without abatement runs higher.

Water use is significant but not catastrophic at the polymerisation step; the heavy water cost in nylon comes downstream, in dyeing.

What recycled nylon recovers

Recycled nylon — usually marketed under the Econyl brand by Aquafil, or via similar processes from Hyosung, Fulgar, and Nilit — is produced from two main feedstocks: post-consumer fishing nets and post-industrial fabric scrap.

The relevant emissions number: published Aquafil LCA data (third-party verified by ICEA / DNV) places Econyl regenerated nylon 6 at roughly 5.7 kg CO₂e per kg of fibre, against virgin nylon 6 at roughly 9.7 kg CO₂e — a reduction of roughly 40 percent in cradle-to-gate emissions (Aquafil, 2023, Econyl LCA Summary).

The water and energy savings are larger in percentage terms because the depolymerisation route skips the most intensive virgin-feedstock steps.

Where the recycled win is smaller than the marketing

Three honest qualifiers.

— The gap is upstream only. Once the yarn is knitted, dyed, finished, sewn, and shipped, the downstream impact is identical between a recycled-nylon piece and a virgin-nylon piece. If the dyeing is dirty, the recycled fibre does not save it.

— End-of-life is unsolved for both. Recycled nylon recycled once is still polyester-elastane blended yarn at the legging stage; the second recycle of a finished elastane-blend garment is not currently industrial. Recycled content reduces the upstream load. It does not close the loop.

— Microfibre shedding is unchanged. A recycled-nylon legging sheds at roughly the same rate as a virgin-nylon legging in laundry testing (De Falco et al., 2019). The shedding problem is a synthetic problem; recycled origin does not address it.

Where it is bigger than the marketing

Two underrated effects.

— N₂O versus CO₂. The headline 40 percent emissions reduction is a CO₂-equivalent number. Because nitrous oxide is a long-lived, high-potency gas, avoiding adipic-acid production at older non-abated facilities is disproportionately valuable. The marginal kg of recycled nylon is most valuable when it displaces older virgin capacity, less valuable when it displaces a modern abated plant.

— Material recovery from fishing nets. Roughly 10 percent of marine plastic waste by weight is abandoned fishing gear (FAO, 2009, Abandoned, lost or otherwise discarded fishing gear). The Econyl ghost-net feedstock is a real diversion, with secondary marine-ecosystem benefit not captured in the LCA carbon number. It is a co-benefit, not a primary metric.

What we use, and why

We use recycled nylon 6 (Econyl-spec) at 78–84 percent of the body weight of our compression pieces, paired with 8 percent virgin elastane (recycled elastane is not yet commercial at our gauge), and a small percentage of polyester thread and TPU waistband structure.

We pay roughly 15–20 percent more for the recycled yarn than the virgin equivalent at our current order volume. The cost difference shows up in the retail price; we do not absorb it. We say so.

We are watching three developments that would change the math:

— Bio-based nylon. Genomatica, Aquafil, and others are commercialising plant-based nylon precursors. Live at small scale; price point not yet competitive at our volumes.

— Recycled elastane. The Hyosung Mipan Regen and similar tracks. Currently available in coarser deniers than we need; gauge is the bottleneck.

— Mechanical-to-chemical hybrid recycling. Pilot facilities for blended-yarn recovery (Carbios, Worn Again, Ambercycle). Industrial scale not yet available.

When any of these passes the cost-and-quality bar at our volume, we will switch and write the next version of this piece.

What this means for a buyer

The choice between a recycled-nylon legging and a virgin-nylon legging is real, and it is roughly a 40 percent reduction in cradle-to-gate fibre emissions. That is meaningful at the kg-of-CO₂e level. It is not the whole sustainability story for the piece.

What matters more, for a buyer who has already chosen activewear in the category: how long the piece lasts on you. A recycled-nylon legging worn 50 times before replacement is environmentally worse than a virgin-nylon legging worn 250 times. The fibre choice is a 40 percent gap. The lifespan choice is a multiple. The wash cycle that delivers the lifespan is in our care guide.