Scientists find microplastics in human bones that are weakening our skeletons

Microplastics are not just in oceans and beaches. They are showing up inside the human body, including tissues that were once considered hard to reach.

Bones are alive, constantly rebuilt by cells that add and remove tissue. When that system is disturbed, strength fades and fracture risk climbs.

Microplastics and bone health

A recent review pulls together 62 studies to explain how tiny plastic particles could influence bone and bone marrow. The effort includes researchers in Brazil, Canada, and France.

One of the scientists leading the discussion is Rodrigo B. Oliveira, coordinator of the Laboratory for Mineral and Bone Studies in Nephrology (LEMON) at the Faculty of Medical Sciences, State University of Campinas in Brazil (FCM-UNICAMP).

His team studies how environmental factors may change bone biology.

“The potential impact of microplastics on bones is the subject of scientific studies and isn’t negligible. For example, in vitro studies with bone tissue cells have shown that microplastics impair cell viability, accelerate cell aging, and alter cell differentiation, in addition to promoting inflammation,” said Oliveira.

What are microplastics?

Scientists use the term microplastics for plastic fragments smaller than 5 millimeters. These pieces can form when bigger plastics break apart or from products that start small.

Your bone marrow is the soft tissue inside bones where blood cells form. It also houses stem cells that can become bone building cells or fat cells.

Microplastics effects on bones

The review describes shifts in cell behavior that matter for strength. Signals that push cells to mature into bone building cells can be blunted, while signals that favor bone breakdown can rise.

In several models, the balance tilts toward osteoclasts, the cells that remove old bone. Too much removal, called bone resorption, leaves the skeleton more fragile over time.

How microplastics reach bones

Scientists have detected plastic particles in human blood. One study measured common polymers such as polyethylene and polystyrene circulating in volunteers.

They have also measured these particles in decedent human brains using chemical fingerprinting methods. A 2025 paper reported higher concentrations in brain tissue than in liver or kidney and noted an increase over recent years.

Most relevant to bones, researchers have now identified plastic fragments in human skeletal tissues.

A recent study documented microplastics in bone, cartilage, and intervertebral discs, with deposition levels in bone averaging in the tens of particles per gram.

How plastics disrupt balance

Cells exposed to microplastics can release inflammatory molecules that nudge the remodeling cycle off course. Reactive oxygen species, a kind of chemical stress, can rise inside bone related cells.

The review also points to effects on mesenchymal stem cells in marrow. These versatile cells may shift away from bone forming fates when exposed to certain plastic particles.

Why this matters for aging

Age and hormonal changes already push the skeleton toward loss. Added cellular stress from microplastics could make a small problem bigger, especially in people with other risks.

The International Osteoporosis Foundation (IOF) reports that hip fractures are projected to almost double by 2050 compared to 2018.

That projection underscores how even modest new risk factors can matter at the population level.

Animal and lab findings

“In this study, the adverse effects observed culminated, worryingly, in the interruption of the animals’ skeletal growth,” said Oliveira.

Researchers have also reported that microplastics can reach deeper bone regions, including marrow. When marrow machinery is disturbed, blood cell formation and bone renewal can both feel the pinch.

How plastics enter body

Plastic particles enter by air, water, and food. Once inside, smaller sizes can travel with the bloodstream and lodge in tissues.

The skeletal system is highly vascular. That network can move circulating particles into areas where bone building and bone removal cells work.

Global microplastics and bones

Plastics production has risen fast over the last two decades. The plastics lifecycle generated about 1.8 billion tons of greenhouse gas emissions in 2019 according to an OECD report.

The same global growth means more potential sources of microplastics. Tires, textiles, packaging, and discarded items all contribute tiny fragments to air, soil, and water.

Future research needs

Human studies that track exposure and bone outcomes are still rare. Standardized measurement methods will help make results easier to compare.

The review highlights several testable ideas. These include whether microplastics accelerate cell aging in bone tissue and whether certain polymer types are more active than others.

There is credible evidence that microplastics interact with bone related cells in ways that could weaken the skeleton over time. There is also direct evidence that these particles can be present in human skeletal tissues.

The open questions are clinical. Scientists are working to learn how much exposure matters, who is most at risk, and which particles matter most.

The study is published in Osteoporosis International.

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