Microplastics in Pee

⚕️ MEDICAL DISCLAIMER: This article is for informational and educational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider before making any changes to your health regimen, diet, or supplement use, especially if you have existing medical conditions or take medications. The information presented here should not be used to diagnose, treat, cure, or prevent any disease.

If microplastics are everywhere (our food, air, and water), then what happens once they’re inside us? Do they build up forever, or can we get rid of them?

Emerging research shows that our body removes most “larger” microplastics naturally. Additionally, our bodies can remove microplastics through urine. We know this as numerous studies have found microplastics in pee. But, the process is far from perfect. Our ability to remove microplastics via urine depends on particle size, shape, chemical properties, and how well your kidneys are functioning. 

Yes, There Are Microplastics in Pee

Multiple studies have detected microplastics in pee samples, confirming that the urinary system offers a pathway for elimination [1–6]. The most direct evidence comes from a preliminary study using micro-Raman spectroscopy, which successfully identified plastic particles in the urine of healthy adult donors [4,5,6].

The types of polymers detected include polyethylene (PE), polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), and nylon (PA66) [3]. Among these, PE and PVC appear to be most abundant. 

How many microplastics, roughly, are we peeing out? One study estimated a median mass of 5.06 μg/g in urine samples [3]. If we pee one liter a day, or roughly 1000 grams per day, then we’re peeing out about 5 micrograms of microplastics a day. In more relatable terms, this is about the weight of a mosquito, a hair, or a grain of sand. Over the course of a year, this could total two grams, or the weight of a dime, a paperclip, or a playing card. Overall, scientists have found that we urinate microplastics and that they pass through our kidneys [3].

How Do Microplastics Enter the Kidneys?

After ingestion or inhalation, microplastics can cross epithelial barriers and enter the bloodstream. Once circulating in the blood, they may be filtered by the glomeruli in the kidneys, which are small blood vessels responsible for removing waste products from the body [3,6].

However, filtration isn’t uniform, meaning that not all microplastics appear to be filtered. Particle size plays a critical role. The microplastics found in urine samples are generally small, often between 4 and 15 micrometers, suggesting that only the tiniest fragments make it through [7,19].

Nanoplastics, which are under 100 nanometers, may behave differently. These particles can bypass typical cellular defenses and potentially undergo endocytosis or macropinocytosis, where they’re absorbed into kidney tubule cells and later secreted into urine [6]. However, much more research is needed before we can definitely say how microplastics and nanoplastics pass through the kidneys. 

The Role of Kidney Physiology In Microplastic Removal

Your kidneys are highly vascularized organs with unique structures. Glomerular filtration acts like a molecular sieve, favoring the excretion of smaller, neutrally charged, and hydrophilic particles. Tubular secretion and reabsorption processes may also contribute to microplastic transport, especially for charged or surface-modified particles [6].

Interestingly, the presence of environmental coatings, such protein-coronas, or protein aggregates, can affect a particle’s interaction with kidney tissue. These coatings may enhance or inhibit recognition by renal transport systems, changing how particles are handled inside the body [6].

This may explain why some studies find variable results when looking for microplastics in kidney tissue itself. Not all particles make it that far, and even fewer may persist long enough to be detected post-mortem [20]. 

Can Microplastics Harm the Kidneys?

Yes, microplastics can harm the kidneys according to several findings. Microplastics in the kidney have been associated with oxidative stress, inflammation, apoptosis (programmed cell death), and tissue fibrosis [7]. Long-term accumulation could impair filtration capacity, promote chronic kidney disease, or worsen existing renal dysfunction. However, more research is needed. 

Some microplastics also leach toxic additives, like bisphenol A (BPA), which are nephrotoxic in their own right. Studies have shown that co-exposure to BPA and microplastics significantly increases damage to kidney proximal tubule cells [14].

For individuals with existing kidney disease, diabetes, or high blood pressure—conditions that already stress renal function—this added burden may accelerate organ decline.

Where Are These Particles Coming From?

The microplastics in pee come from many different sources. Firstly, food and water, such as bottled water, seafood, and packaged goods are common sources [1,3,12,13]. They can also come from personal care products, like toothpaste and cosmetics [1]. Microplastics also enter our bodies from the air, where they then translocate into the bloodstream and reach our kidneys [3,5,9]. Lastly, microplastics may come from plastic containers, utensils, indoor dust, and more [1,3]. 

Some evidence suggests correlations between high microplastic excretion and lifestyle factors such as frequent bottled water consumption and high use of single-use plastics [3,13].

There’s A Mixed Picture on Excretion Efficiency

While the body can remove some microplastics, the extent is unclear. Smaller, hydrophilic particles are more likely to be excreted via urine. Larger or more hydrophobic particles may accumulate in tissues or be excreted through other pathways, like feces or bile [3,7,10].

Kidney health also matters. Damaged kidneys may filter less efficiently or retain harmful substances longer. That’s why researchers are calling for more targeted studies in vulnerable populations: children, the elderly, and patients with chronic kidney disease.

How Can I Lower My Exposure To Microplastics

Although some studies have found that most microplastics pass through us, the ones that remain can potentially cause long-term health effects. Consequently, for those of us concerned about our health, it’s important to lower our exposure to microplastics as much as possible. There are many small, simple actions that you can take each day to lower the amount of microplastics you consume. This is why we developed the Deplasto platform. 

Our platform, consisting of a science-backed supplement, a microplastic intake app, and lifestyle recommendations is intended to help you avoid microplastics. Our all-natural supplement is formulated to support your body’s natural detoxification defenses, including oxidative stress management, cellular repair, and antioxidant support. Our microplastic intake app is designed to show you an estimate of your daily exposure, with every datapoint backed by scientific studies, to help you understand how you can best avoid microplastics. Lastly, given that it’s nearly impossible to completely avoid microplastic exposure, we have a plethora of lifestyle recommendations designed to help you make small changes for big impacts. 

Overall, we believe that the best way to eliminate microplastics begins with you and the changes you make to your daily life. Over time, collectively, we can make a significant impact on our health and the environment.

Sources

1. Detection of microplastics in human tissues and organs – A scoping review
2. Important Factors Affecting Induction of Cell Death, Oxidative Stress and DNA Damage by Nano- and Microplastic Particles In Vitro 
3. Internal and external microplastic exposure in young adults – A pilot study involving 26 college students in Changsha, China
4. Mapping Microplastics in Humans – Analysis of Polymer Types, and Shapes in Food and Drinking Water – A Systematic Review 
5. Micro-nanoplastics and cardiovascular diseases – Evidence and perspectives
6. MicroRaman spectroscopy detects the presence of microplastics in human urine and kidney tissue 
7. Micro/nano plastics in the urinary system – Pathways, mechanisms, and health risks 
8. Microplastic and human health with focus on pediatric well-being – A comprehensive review and call for future studies 
9. Microplastics and Nanoplastics in Atheromas and Cardiovascular Events
10. Microplastics and nanoplastics in cardiovascular disease – A narrative review with worrying links
11. Microplastics exposure – Implications for human fertility, pregnancy and child health
12. Microplastics in the Human Body – Exposure, Detection, and Risk of Carcinogenesis – A State-of-the-Art Review 
13. Consumption of Bottled Water and Chronic Diseases – A Nationwide Cross-Sectional Study
14. Microplastics and Kidneys – An Update on the Evidence for Deposition of Plastic Microparticles in Human Organs, Tissues and Fluids and Renal Toxicity Concern 
15. Coexposure to microplastic and Bisphenol A exacerbates damage to human kidney proximal tubular cells
16. Identification and Visualization of Polystyrene Microplastics/Nanoplastics in Flavored Yogurt by Raman Imaging
17. Identification of micro- and nanoplastic particles in postnatal Sprague-Dawley rat offspring after maternal inhalation exposure throughout gestation 
18. Identification of micro- and nanoplastic particles in postnatal sprague-dawley rat offspring after maternal inhalation exposure throughout gestation
19. Mind over Microplastics – Exploring Microplastic-Induced Gut Disruption and Gut-Brain-Axis Consequences
20. Human Exposure to Microplastics and Its Associated Health Risks
21. Integrating aggregate exposure pathway and adverse outcome pathway for micro/nanoplastics – A review on exposure, toxicokinetics, and toxicity studies
22. Microplastics dampen the self-renewal of hematopoietic stem cells by disrupting the gut microbiota-hypoxanthine-Wnt axis
23. Adverse health effects of exposure to plastic, microplastics and their additives – Environmental, legal and policy implications for Israel
24. Long-Term Exposure to Polystyrene Microspheres and High-Fat Diet-Induced Obesity in Mice – Evaluating a Role for Microbiota Dysbiosis
25. Microplastic exposure disturbs sleep structure, reduces lifespan, and decreases ovary size in Drosophila melanogasters
26. Microplastics are associated with elevated atherosclerotic risk and increased vascular complexity in acute coronary syndrome patients
27. Microplastics caused embryonic growth retardation and placental dysfunction in pregnant mice by activating GRP78/IRE1α/JNK axis induced apoptosis and endoplasmic reticulum stress 
28. Microplastics – Detection in human samples, cell line studies, and health impacts