Microplastics and Nanoplastics: Differences, Sources, and Health Impacts

Health Line

21-05-2025

Plastic breaks down into tiny micro- and nanoparticles that may potentially impact the reproductive and digestive systems and raise your risk of cancer. But these are just early findings based on low levels of evidence.

With an increase in research about the impact of plastics on our health and the environment, you might have come across the terms 'nanoplastics' and 'microplastics.'
Here's how the two terms are defined, and what they mean for your health.
Differences between microplastics and nanoplastics
One way to distinguish between microplastics and nanoplastics is by size, which their prefixes point to.
'Micro-' denotes a size of one millionth, and 'nano-' denotes a size of one billionth. Simply put, this means that nanoplastics are smaller than microplastics.
According to the Food and Drug Administration (FDA):
Microplastics are typically considered to be less than 5 millimeters in size in at least one dimension.
Nanoplastics are typically considered to be less than 1 micrometer in size in at least one dimension.
But the FDA doesn't have standard definitions for the sizes of these plastics. These descriptions are used for reference purposes only.
Where do microplastics and nanoplastics come from?
Both micro- and nanoplastics come from a human-made material — plastic. Plastic is a major or partial component of many household products or items used daily, such as:
appliances
toys
tools
storage containers
tires
clothing
You'll know something is made from plastic if it has a label that contains:
polystyrene (styrofoam)
polyethylene
nylon
polytetrafluoroethylene (teflon)
polyvinyl chloride
polypropylene
polyester
You may also notice a recycling symbol or a small triangle with a number between 1 and 7 inside, which denotes the type of plastic the item is made from.
Because most plastics don't break down in the environment (biodegrade) like paper, cotton, and other plant-based materials, they break down into smaller micro- and nanoparticles.
These microplastics and nanoplastics may contaminate soil and water if improperly disposed of, and if adequate safety precautions are not taken to minimize their contamination in the food and water supply.
They may also be present in the air and absorbed through some personal care products.
What are the potential health impacts of microplastics and nanoplastics?
The FDA suggests that, based on available research as of 2024, the levels of microplastics and nanoplastics in foods and the environment are not enough to pose a risk to human health.
As 2020 research suggests, the knowledge on levels of exposure from ingestion, inhalation, and skin contact is limited, and more long-term studies in humans are needed.
But a 2021 research review found that microplastics and nanoplastics may impact the immune, respiratory, gastrointestinal, and hepatic (liver-related) systems.
A more recent review ' suspects ' potential links to harm in human reproductive and digestive systems, as well as a link to colon and lung cancer.
Other research suggests that micro- and nanoplastics may accumulate in fish brains and human semen and be released upon chewing gum and steeping nylon or polyethylene terephthalate teabags.
Some current theories propose that once in your cells, micro- and nanoplastics may disrupt or change their functioning by causing:
Still, the level of evidence for these findings is low
Regardless of what recent studies have found, most state that the effects likely depend on the size, type, and amount of plastic ingested, inhaled, or absorbed, which is difficult to measure. Experts are calling for more research, because how microplastics and nanoplastics may affect body systems is still not well understood.
Should you be worried about consuming plastic?
Plastic is a major component of today's manufacturing processes and won't likely be going away anytime soon.
Most published studies can only prove an association, not causation, between microplastics and nanoplastics and health impacts. Experts are calling for more research before reaching any firm conclusions.
However, you can still find ways to minimize your exposure, such as:
choosing clothing that's made from natural materials, such as cotton, linen, silk, or wool
limiting your use of plastic storage containers, especially for food, and opting for glass or other alternatives instead
filtering water, especially if it's from the tap