WHAT IS A LIFE CYCLE ASSESSMENT (LCA)?
A Life Cycle Assessment (LCA) is a method used to measure a product’s environmental impact across its entire life cycle — from raw materials and production to transport, use, and end-of-life.
It may sound technical, but the effect is very concrete: LCA reveals where the footprint actually occurs — and how small design choices can lead to major reductions in CO₂, waste, and resource use.
This example is based on a DTU semester project in Production Engineering (Diploma Engineer track), where we use LCA to understand where in the life cycle a toothbrush’s environmental footprint typically peaks. With a toothbrush, the impact is rarely just about the plastic itself — but about the combination of mixed materials (handle + bristles), packaging per unit, large-scale transport volumes, and the fact that the product often ends up as residual waste.
THE TOOTHBRUSH’S HIDDEN ENVIRONMENTAL FOOTPRINT
Even simple everyday products can have a surprisingly large environmental footprint — the toothbrush is a clear example. To understand where the footprint occurs, we use LCA as a method — exactly as we learn it at DTU.
LIFE CYCLE ASSESSMENT (LCA) — AN EXAMPLE FROM DTU
At the Technical University of Denmark (DTU), we work with Life Cycle Assessment (LCA) as an analysis method to evaluate a product’s total environmental impact across its entire life cycle.
Important: This overview is inspired by the teaching and the method — and is not a full or public LCA report. We do not share any case data, but use LCA logic to explain the typical phases and “hotspots” that often drive the footprint of everyday products.
But before we can point to solutions, we first need to understand where the environmental impact actually occurs in the toothbrush’s life. That’s exactly what Life Cycle Thinking helps with: shifting the focus from “material alone” to the full chain — from raw materials to end-of-life.
Below, we use LCA logic as a framework and walk through the most typical phases and hotspots that often drive the footprint of everyday products like toothbrushes.
HOTSPOTS IN THE TOOTHBRUSH LIFE CYCLE
Hotspots are the toothbrush’s “weak points” in the life cycle — where materials, energy, and transport can push the footprint unnecessarily high. The table shows where — and what you can do about it.
| LCA PHASE | WHAT HAPPENS | TYPICAL HOTSPOTS | WHAT YOU CAN DO |
|---|---|---|---|
| RAW MATERIALS | Materials are extracted and processed | Plastic types, energy for raw material production | Material substitution, less material use |
| PRODUCTION | Manufacturing, molding, assembly | Electricity use, waste, chemicals | Lean processes, less waste, cleaner energy |
| TRANSPORT | Transport from factory to market | Air vs. sea freight, packing efficiency | Optimize routes, avoid air freight, improve load utilization |
| USE | The product’s use phase | Replacement frequency, lifespan | Longer lifespan, replaceable head |
| END-OF-LIFE | Disposal / recycling | Mixed materials, low recyclability | Design for disassembly, mono-materials, take-back |
LCA STEP BY STEP (RAW MATERIALS → PRODUCTION → TRANSPORT → USE → END-OF-LIFE)
To make it practical, we use the LCA structure as a checklist: where are the hotspots — and which design moves make the biggest difference? An LCA calculation typically covers every phase of a product’s life. In practice, it’s about identifying where the impact is highest — and where improvements deliver the most effect.
1) RAW MATERIALS: PLASTICS, FIBERS & “HIDDEN” INPUTS
This hotspot often comes down to the material’s origin (fossil vs. recycled), the total material volume, and which additives are used for strength and durability.
- Typical improvement: Reduce material use, avoid unnecessary material mixes, and choose recycled input where it makes sense.
2) PRODUCTION: ENERGY, WASTE & PROCESS CHOICES
Production can become a silent driver if the design requires many parts, many process steps, or leads to higher defect rates and rework.
- Typical improvement: Design for fewer parts, lower waste, and a more stable process (fewer defects and fewer extra steps).
3) TRANSPORT: SMALL PRODUCTS, HUGE VOLUMES
Toothbrushes are small per unit, but they’re often shipped in massive volumes. Packaging, load efficiency, and route choices can quickly become hotspots.
- Typical improvement: Compact packaging, better load utilization, fewer “air miles,” and shorter routes where possible.
4) USE: LIFETIME & FUNCTIONAL UNIT
In LCA, a product is typically assessed by the function it delivers over time (the functional unit). The shorter the lifetime and the faster replacement happens, the higher the footprint per use.
- Typical improvement: Design for longer life and provide clear guidance so the product is used as intended.
5) END-OF-LIFE: SORTING, RECYCLING & DESIGN FOR DISASSEMBLY
Many toothbrushes end up as residual waste because they are hard to sort or made from materials that can’t be separated.
- Typical improvement: Fewer material types, less glue/fusion, and design for disassembly or easier sorting.
OVERALL NOTES — NOT A FULL LCA REPORT
The key takeaway is rarely “one perfect material.” It’s the system: fewer material types, simpler design, lower waste, smarter packaging and transport — and an end-of-life pathway that can actually work in practice. That’s where LCA moves the most.
LIFE CYCLE ASSESSMENT (LCA) — FAQ
What is a Life Cycle Assessment (LCA)?
A Life Cycle Assessment (LCA) measures a product’s total environmental impact across its entire life cycle — from raw materials and production to transport, use, and end-of-life.
How do you do an LCA analysis?
An LCA analysis is done by defining the functional unit and system boundaries, collecting data, and calculating impacts for each phase of the product’s life cycle.
What are LCA calculations used for?
LCA calculations are used to compare materials and solutions, reduce CO₂ footprint, and prioritize the design choices that create the biggest environmental benefit.
WHY LCA MATTERS FOR EVERYDAY PRODUCTS
LCA shows that even small products can have complex footprints — and that improvements rarely come from just one change. With life cycle thinking, you can prioritize the changes that deliver the most impact: materials, waste, packaging, transport, and end-of-life.
If you want to see how the same LCA logic can be applied in fashion and production, read our page about textile waste in clothing production.
Want a simple LCA checklist for everyday products? Contact us — and we’ll share a short version of the method we use at DTU (without any case data).
Related: plastic waste and microplastics.
And if you want to go deeper into regenerated materials, you can see our collaboration with ECONYL®.
Life cycle assessments of everyday products are closely connected to broader discussions about material waste and production systems.
You can explore how similar life cycle principles are applied in apparel production through our
Life-Cycle approach to responsible clothing production.
