Modal and TENCEL Lyocell come from the same parent company, use the same general category of raw material, and get grouped together constantly in sustainable fashion conversations. If you have done any research into plant-based activewear, you have almost certainly seen them listed as interchangeable alternatives.
They are not interchangeable. The production processes are different, the fiber properties are different, and for activewear specifically, the performance profiles diverge in ways that matter during a workout. The confusion is understandable but worth clearing up.
What modal actually is
Modal is a regenerated cellulose fiber, produced by dissolving wood pulp, typically beech wood, in a chemical solvent and extruding it into fiber form. Lenzing AG, the Austrian textile company that also produces TENCEL, manufactures a version of modal under the TENCEL Modal brand name using a closed-loop production process.
Not all modal on the market is produced this way. Modal is a generic fiber category, meaning any manufacturer can produce and sell a fiber called modal using a range of production methods. When you see modal on a label without a brand name attached, the production standards are unknown. When you see TENCEL Modal specifically, Lenzing's closed-loop credentials apply.
This label distinction matters more than most people realize when making purchasing decisions based on environmental or health grounds. The full breakdown of TENCEL vs lyocell vs modal covers the production and fiber differences across all three.
What TENCEL Lyocell is
TENCEL Lyocell is also produced by Lenzing AG, also from sustainably sourced wood pulp, also through a closed-loop solvent process. The solvents differ: TENCEL Lyocell uses NMMO (N-methylmorpholine N-oxide), while conventional modal production uses sodium hydroxide and carbon disulfide. Lenzing's closed-loop modal version uses a modified process with lower environmental impact than conventional modal manufacturing.
The closed-loop TENCEL Lyocell process recovers more than 99% of the NMMO solvent per production cycle, according to Lenzing's published sustainability data. The fiber itself carries OEKO-TEX certification, confirming the finished material has been tested for harmful substances. Understanding whether lyocell and TENCEL are the same is useful context before reading any activewear label.
Where the performance difference lives
Both modal and TENCEL Lyocell are soft. Both are breathable. Both are more moisture-aware than conventional polyester. At rest and in low-intensity movement, the difference between them is not significant for most wearers.
The gap opens under exercise conditions. TENCEL Lyocell's fiber structure is hygroscopic in a specific way that moves moisture into and through the fiber, maintaining a drier skin surface than cotton and cotton-adjacent regenerated fibers during active wear. A 2014 study in Fibers and Polymers by Kaplan et al. confirmed this moisture management advantage under active wear conditions.
Modal's moisture behavior is closer to cotton than to TENCEL Lyocell. It absorbs moisture and tends to hold it rather than releasing it efficiently. In a low-intensity context, this is comfortable. In a sustained workout with significant perspiration, it becomes the same moisture-retention limitation that rules out cotton for serious exercise.
Durability under mechanical stress is another separation point. TENCEL Lyocell fibers maintain their tensile strength when wet, which is relevant for activewear that is mechanically stressed during both exercise and washing. Modal fibers, like other viscose-adjacent materials, weaken when wet, which accelerates degradation under the repeated wet-dry cycling of regular workout wear.
The pilling question
Pilling is a practical concern for any fabric used in high-friction activewear applications. TENCEL Lyocell's longer fiber length gives it better resistance to pilling than modal. Over time, a TENCEL Lyocell legging will maintain its surface quality more reliably than a modal equivalent under equivalent use conditions.
This is not a small consideration for a garment at a price point that justifies expecting multi-year wearability.
Where modal does make sense
Modal's softness profile makes it genuinely well-suited for low-intensity wear, athleisure, and any context where moisture management under effort is not the primary requirement. A modal loungewear set or a low-impact yoga top plays to the fiber's strengths. A modal legging for a high-intensity interval session does not.
TENCEL Modal specifically, produced under Lenzing's closed-loop credentials, is also a reasonable choice for casual activewear if the brand using it can confirm the Lenzing provenance. Generic modal without brand attribution is a different and less traceable material. For those looking at modal activewear alternatives for workout use, the path toward better performance is clear.
Why Bellissima chose TENCEL Lyocell over modal
The decision came down to performance under exercise conditions and durability under repeated use. Modal's moisture management limitation under effort and its reduced wet-strength relative to TENCEL Lyocell ruled it out for a performance activewear line. The Sempre Leggings and bras use 92% TENCEL Lyocell because it was the natural fiber that performed during a workout, not just while standing still. For a clear explanation of what TENCEL Lyocell is and why the production process matters, the full story is worth reading.
The short answer
A label that says modal and a label that says TENCEL Lyocell are not describing the same thing, even though they share a parent company and a general category. TENCEL Lyocell is the stronger choice for activewear. Modal is the stronger choice for anything where softness and casual comfort are the primary requirements and workout performance is not.
Knowing the difference means you can read a label and actually understand what you are buying.
Why this conversation matters more in 2026
In April 2026, the Texas Attorney General opened a civil investigation into Lululemon over the potential presence of PFAS (per- and polyfluoroalkyl substances) in activewear marketed to health-conscious consumers. The brand confirmed PFAS had been used in its durable water repellent products before being phased out in early 2024. A class action lawsuit in California made parallel allegations about misleading sustainability marketing.
The case mattered beyond Lululemon. It confirmed that synthetic fabric chemistry was being scrutinized at the state attorney general level, and that the gap between brand wellness positioning and what is actually in the fabric had become a consumer protection question. California and New York implemented broader PFAS-in-apparel bans in January 2025. Thirty state attorneys general had initiated litigation against PFAS manufacturers by the end of 2024.
What this means for anyone choosing activewear: the fiber content label is not the full picture, and brand claims are not the same as independent third-party certification on the finished textile. Understanding what the base fiber is, and how the finished garment has been verified, is the practical question this category now demands.
Sources
Texas Attorney General. (2026, April 13). Attorney General Ken Paxton Launches Investigation into Lululemon Over Potential Presence of Toxic "Forever Chemicals" in Activewear. texasattorneygeneral.gov.
U.S. Environmental Protection Agency. (2024). Our Current Understanding of the Human Health and Environmental Risks of PFAS. EPA.gov.
Kaplan, S., et al. (2014). Thermal comfort of lyocell and other fibers in active wear. Fibers and Polymers, 15(6).
Lenzing AG. (2023). TENCEL Lyocell and TENCEL Modal fiber sustainability data. Lenzing Sustainability Report.
OEKO-TEX Association. (2023). OEKO-TEX Standard 100 certification criteria. OEKO-TEX Technical Bulletin.
Woodings, C. (2001). Regenerated cellulose fibres. Woodhead Publishing.