Most "sustainable fashion" claims rest on a tool most shoppers have never heard of: the Lifecycle Assessment, or LCA. It is the closest thing the industry has to a scientific measurement of a garment's environmental footprint — and, according to a systematic review of LCA practice in fashion published in Discover Sustainability by Komal Dhiwar and Madhura Bedarkar, it has persistent weaknesses that make brand-to-brand comparisons unreliable. The practical takeaway for shoppers is not cynicism but a specific skill: knowing which questions expose whether a claim is a comprehensive assessment or selective marketing.
Beyond the Buzzwords: What is Sustainable Fashion?
"Sustainable" is not a defined term, which is precisely why the industry has leaned on data to answer the question of what deserves the label. As Beth Jensen of Textile Exchange has observed, the apparel sector — long rooted in creativity and design — has had to develop its understanding of the data and science needed to unpack the ongoing question of what is actually "sustainable." The LCA is the industry's primary answer to that question.
An LCA attempts to trace a garment's environmental impact across its entire life: raw material extraction (cotton farming or polyester production), manufacturing and processing, distribution, the consumer use phase, and finally disposal or recycling. A "cradle-to-grave" assessment covers all of these stages; a "cradle-to-gate" assessment stops when the product leaves the factory, excluding what happens after purchase. That distinction matters enormously, because the use phase — washing, drying, ironing — and end-of-life treatment can be significant parts of a garment's footprint, and they are also the stages a brand controls least.
The Promise and Pitfalls: Why LCA is Used, and Why It's Flawed
Brands use LCAs for good reasons. The methodology is governed by the ISO 14040 and 14044 standards, which Dhiwar and Bedarkar describe as widely accepted among LCA practitioners and an essential instrument for systems-oriented environmental performance analysis across industries. LCAs give brands a way to substantiate green claims, understand their supply chains, and prepare for regulatory developments such as the EU's product environmental footprint rules and Digital Product Passport initiatives, which are pushing the industry toward more documented impact reporting.
But the same review finds that the lack of standardized LCA methodologies limits the reliability and practical applicability of LCA findings, hindering the ability to benchmark environmental performance and make evidence-based decisions toward sustainable transformation in fashion. Crucially, this is a structural problem, not necessarily a sign of deception. The standards that make LCAs credible also allow flexibility in how they are conducted — and that flexibility is where marketing opportunities live.
Key Limitations: Inconsistent Boundaries, Data Gaps, and Missing Impacts
Dhiwar and Bedarkar's review highlights recurring problems in LCA studies, such as challenges in accessing reliable primary data and reliance on generic secondary data, along with inconsistencies in defining system boundaries, allocation methods, and functional units. Furthermore, these studies often inadequately incorporate emerging priorities like circularity, microplastic emissions, and biodiversity impacts. Together, these impede cross-study comparability and hinder the reliability of sustainability claims.
System boundaries are the first trap. One brand's "cradle-to-gate" number cannot be compared with another's "cradle-to-grave" number, yet both may appear in marketing as a simple footprint figure. The review's own screening process illustrates how common this is: the authors discarded studies that lacked clear definitions of their lifecycle boundary, as well as studies that omitted an allocation methodology when one was clearly needed.
Allocation — deciding how to divide environmental burdens when a process produces multiple outputs, or how to credit recycling — is another. Different, defensible allocation choices can significantly alter results. Meanwhile, many assessments focus narrowly on carbon and water, leaving impacts like microplastic pollution and biodiversity essentially invisible. The EU's Product Environmental Footprint rules, by contrast, require all sixteen impact categories to be evaluated — a reminder that a single-metric claim is a choice, not a necessity.
Your Critical Checklist for Sustainable Fashion Claims
The academic critiques translate directly into questions a shopper can ask. Each row below pairs a documented weakness in fashion LCA practice with the question it should trigger — and what a credible answer looks like. Use it on any claim, from a product-page footprint figure to a "greener than conventional cotton" comparison.
| LCA aspect | Documented limitation | Question to ask | What a credible answer looks like |
|---|---|---|---|
| Scope of assessment | Results vary depending on which lifecycle stages are included; "cradle-to-gate" excludes use and disposal, and ISO standards allow this flexibility. | Does the claim state its boundary — cradle-to-gate or cradle-to-grave? | The boundary is named explicitly, and the claim does not compare numbers from different scopes. |
| Impacts measured | Many assessments center on carbon and water while weakly incorporating circularity, microplastic emissions, and biodiversity. | Is this only a carbon or water figure? What other categories were assessed? | Multiple impact categories are reported, or the brand acknowledges which ones were excluded. |
| Data transparency | Access to reliable primary data is limited; generic database estimates may not reflect a specific product's actual impact. | Is the data from the brand's own supply chain, or from generic industry databases? | Facility-specific measurement is described, and data sources, assumptions, and limitations are documented — the transparency ISO 14044 demands. |
| Comparability | Inconsistent boundaries, allocation techniques, and functional units make cross-study comparison unreliable. | Is the brand comparing its product to a "conventional" alternative — and is that comparison like-for-like? | Any public comparative claim has been reviewed by independent experts, as ISO 14044 requires for public superiority claims. |
Two rules of thumb follow from this table. First, a claim that answers none of these questions — no stated boundary, no data source, single metric, vague comparison — should be treated as marketing, not measurement. Second, a brand that answers most of them, and openly states what its assessment leaves out, is demonstrating the transparency the methodology itself demands.
Making Informed Choices: Beyond the Numbers
None of this means LCA-based claims are worthless. The methodology remains the industry's best available tool, and the problems documented by Dhiwar and Bedarkar stem largely from the flexibility the standards permit — inconsistent boundaries, allocation choices, and data sources — rather than necessarily from intentional deception. Textile Exchange's Jensen argues the industry needs to move toward more holistic assessment; until it does, the burden of scrutiny falls partly on the shopper.
The decision, then, is to critically evaluate fashion brand sustainability claims by applying a structured set of questions derived from known LCA limitations, rather than accepting claims at face value. The measurable indicator of success is simple: the reader can identify specific gaps or inconsistencies in a brand's reported LCA scope, data, or impact categories. The next time a product page presents a footprint number, check whether it names its lifecycle boundary, its data sources, and its impact categories. If it does all three, you have a genuinely assessed claim. If it does none, you have a buzzword — and now you can say exactly why.
