Can polystyrene microplastics affect muscle cells?
Yes, in lab cells. A 2026 Toxicology study found polystyrene microplastics disrupted muscle-building signals, increased atrophy markers, and damaged mitochondria in mouse muscle cells.
What is actually in it
Microplastics are tiny plastic pieces smaller than 5 millimeters. People can swallow them from food packaging, plastic containers, bottled water, takeout packaging, and dust that settles on food.
Polystyrene is one plastic type used in some food packaging. The 2026 study on this page tested polystyrene microplastics in muscle cells, not in people eating food from plastic.
What the research says
A 2026 Toxicology study exposed differentiated C2C12 mouse muscle cells to 1 micrometer polystyrene microplastics for 24 hours.
The cells showed higher reactive oxygen species at concentrations of 100 to 500 micrograms per milliliter. The microplastics also increased muscle atrophy markers, including myostatin, atrogin-1, and MuRF1.
The study found lower muscle protein synthesis signals, including MyoD1, MyoG, MHC, and overall protein synthesis. It also found weaker IGF-1, PI3K, Akt, and mTOR signaling, plus mitochondrial swelling, lower ATP production, and lower mitochondrial function markers.
This is strong cell-level evidence that polystyrene microplastics can disturb muscle-cell health. It does not prove that normal food or water exposure causes muscle loss in people.
What to do next
Use glass for hot food, leftovers, sauces, and acidic foods. Do not microwave plastic. Replace scratched plastic containers first. These simple swaps lower repeat plastic contact without turning your kitchen upside down.