Are compostable PLA food containers safer than regular plastic?
Not clearly. A 2025 mouse study found PLA microplastics caused liver, intestine, metabolism, and gut bacteria changes.
What's actually in it
PLA is a common bioplastic used in some compostable cups and food containers. It is made from plant starch, but it is still plastic.
Compostable does not mean it breaks down in your body. It also does not mean it is better for hot drinks or food contact.
What the research says
A 2025 study in Journal of Hazardous Materials exposed mice to polyethylene microplastics and PLA microplastics from food containers for 4 weeks.
Both plastic types changed metabolism and gut bacteria. PLA microplastics caused stronger changes in lipid metabolism and more serious liver and intestine damage than polyethylene microplastics in this mouse study.
This does not prove one compostable cup will harm a person. It does show that PLA microplastics are not automatically safer just because the cup says compostable.
For hot drinks and daily use, choose glass, ceramic, or stainless steel instead of disposable PLA cups.