Microplastics and Melatonin

In the past five years or so, Microplastics (MPs) have become a household word and with each passing year we have learned more and more about the dangers of microplastics to human health.

One of the main problems with MPs that we are seeing with regular reporting around the world is they are essentially interwoven into our lives because they are everywhere in our environment. To highlight this point, I asked ChatGPT to tell me 30 ways that humans are currently being exposed to MPs and these are the results of that query :

Here’s a comprehensive list of 30 sources of microplastics that humans are exposed to through food, water, air, and products:

Food & Beverage Sources

1. Bottled water – one of the most concentrated sources.

2. Tap water – lower levels than bottled, but still present.

3. Seafood (fish, shellfish, mollusks) – microplastics accumulate in marine animals.

4. Salt (especially sea salt and rock salt) – contains trapped microplastics.

5. Honey – studies show detectable levels.

6. Sugar – refined sugar can be contaminated during processing.

7. Beer – especially those brewed with contaminated water.

8. Soft drinks – due to water and plastic bottling.

9. Canned foods – from plastic linings in cans.

10. Dairy products (milk, cheese) – microplastics enter via feed, water, or packaging.

Household & Packaging Sources

11. Plastic food packaging – leaches particles into food.

12. Tea bags (plastic-containing types) – steeping releases millions of microplastic particles.

13. Plastic kitchenware (cutting boards, containers) – wear and tear releases microplastics.

14. Cling film (plastic wrap) – sheds microplastics directly onto food.

15. Plastic water pipes – friction and degradation release particles.

16. Cooking with non-stick pans – damaged coatings can shed microplastics.

Clothing & Textiles

17. Synthetic clothing (polyester, nylon, acrylic, spandex) – sheds fibers when worn or washed.

18. Carpets & rugs – especially synthetic fiber types.

19. Upholstery & furniture fabrics – constant shedding of fibers.

20. Laundry dryer exhaust – airborne fibers released during drying.

Airborne & Dust Sources

21. Indoor dust – a major inhalation pathway.

22. Outdoor air pollution – tire and road wear particles.

23. Paint dust (buildings, ships, road markings) – breaks down into microplastics.

24. Cosmetics & personal care products (exfoliants, toothpaste, glitter) – microbeads and synthetic polymers.

25. Household cleaning products – scouring pads, cleaning wipes.

Other Environmental Sources

26. Soil and crops – fertilizers, sludge, and irrigation water contaminate crops.

27. Drinking from disposable cups – especially plastic-lined paper cups.

28. Baby bottles & formula preparation – plastic bottles shed millions of particles.

29. Chewing gum – many brands use synthetic polymers (plastics) as the base.

30. Cigarette filters – made from cellulose acetate, a plastic that breaks into microfibers.

In short: we eat, drink, and breathe microplastics daily. The largest contributors are packaging, bottled water, seafood, textiles, and airborne fibers.

As you can see from the above list, MPs are interwoven into our lives in such a way that it is essentially impossible to avoid them in any meaningful way!

So what health problems are MPs thought to cause. For that answer, I asked ChatGPT what are 25 health issues that microplastics are associated with? I asked for "associated with" instead "caused by" because cause and affect may not have been established yet for many health issues in relation to MPs. Here is what ChatGPT came up with :

Cardiovascular & Circulatory

1. Atherosclerosis (artery plaque buildup)

2. Blood clot formation (thrombosis risk)

3. Hypertension (high blood pressure)

4. Heart attack risk (myocardial infarction)

5. Stroke risk (cerebrovascular damage)

Neurological

6. Neuroinflammation (linked to Parkinson’s & Alzheimer’s processes)

7. Cognitive decline / memory impairment

8. Anxiety and depression-like symptoms (seen in animal models)

9. Neurodegenerative disease acceleration

10. Blood–brain barrier disruption

Respiratory

11. Asthma exacerbation

12. Chronic obstructive pulmonary disease (COPD) worsening

13. Pulmonary fibrosis (lung scarring)

14. Reduced lung capacity / function

15. Increased lung cancer risk (chronic exposure)

Digestive & Liver

16. Gut microbiome disruption (dysbiosis)

17. Intestinal inflammation (colitis-like symptoms)

18. Leaky gut syndrome (barrier dysfunction)

19. Liver toxicity / non-alcoholic fatty liver disease (NAFLD)

20. Gallbladder / bile duct inflammation

Endocrine & Reproductive

21. Hormonal disruption (endocrine mimicry from plasticizers)

22. Reduced sperm quality & fertility

23. Menstrual irregularities / ovarian dysfunction

24. Fetal developmental issues (placental microplastic penetration)

25. Thyroid dysfunction

Key Mechanisms Behind These Problems:

• Oxidative stress → DNA, protein, and lipid damage
• Chronic inflammation → accelerates aging & disease
• Endocrine disruption → mimics or blocks natural hormones
• Bioaccumulation → microplastics can lodge in organs long-term

The strongest evidence so far is for inflammation, oxidative stress, immune disruption, reproductive toxicity, and gut/lung health effects. But since research is still young, many of these are “possible or likely” rather than proven in humans.

Melatonin for Microplastics Removal

Earth Clinic does not currently have a "Microplastics Remedy Page", so what can we do to try and protect ourselves from the health problems associated with microplastics?

Melatonin

Since we can't avoid microplastics, what can we possibly do to help protect against the many health issues that microplastics pose for humans? This quote from above about how MPs do their damage, ' The strongest evidence so far is for inflammation, oxidative stress, immune disruption, reproductive toxicity, and gut/lung health effects ', gives a clue as to what and where to look. This quote points to causes that melatonin has shown itself to work against through its various methods of action. That sounds good, but is there actual science to support that idea? So I've been thinking about this question for awhile now and had recently noticed an influx of studies over the past three years testing melatonin in plants and animals exposed to MPs.

While these are only plant and animal studies they do look quite promising. You may be wondering what good is a plant study for this purpose, but you only have to remember that one source of microplastics for humans is from fruits and vegetable and that makes the importance clear. The animal studies suggest how melatonin may act in humans to work against the negative health effects of microplastics.

In this first plant study done in 2021 it is shown that melatonin offers benefit to wheat and suggests potential benefit to wheat that is grown in soils polluted with microplastics :

https://pubmed.ncbi.nlm.nih.gov/34392562/

Here is a compelling quote from the study :

' These results suggest that melatonin could alleviate the adverse effects of nanoplastics on wheat, and exogenous melatonin application might be used as a promising management strategy to sustain crop production in the nanoplastic-polluted soils. '

In this next animal study done in 2022 in mice to show that MPs can cause pulmonary fibrosis and melatonin may offer some benefit :

https://www.sciencedirect.com/science/article/pii/S0147651322000781?via=ihub

Here are some interesting highlights from the study :

• Inhalation of polystyrene microplastics induced pulmonary fibrosis in mice.
• Exposure to polystyrene microplastics induced oxidative stress and alveolar epithelial injuries.
• Polystyrene microplastics exposure activated Wnt/β-catenin signaling pathway.
• Melatonin can alleviate the polystyrene microplastics related pulmonary fibrosis.

In this next study done in August 2022 in zebrafish exposed to polystyrene microplastics melatonin showed health benefit for the zebrafish :

https://www.sciencedirect.com/science/article/pii/S0147651322005942?via=ihub

Here are some highlights from the study :

• PS exposure induced aberrant development of Cap motor axons and abnormal locomotor behavior in zebrafish.
• PS exposure triggered oxidative stress, apoptosis and aberrant proliferation in zebrafish.
• Melatonin (MT) attenuated neurodevelopmental toxicity of PS by activating nrf2 - isl2a axis.

This next plant study done in October 2022 discusses the concerns for plants exposed to MPs :

https://pmc.ncbi.nlm.nih.gov/articles/PMC9589797/

Here is a relevant quote from the article :

' This paper also concludes by providing an outlook approach of applying exogenous melatonin and introducing engineered plants that would enhance stress tolerance against MPs/NPs. '

Importantly about the very lengthy article link above, it is clear that the agricultural industry is making efforts through various means to remedy the problem of MPs and NPs in agriculture.

In this next animal study done in February 2023, they show how environmental accumulation of MPs in rats worsens liver ischemia reperfusion injury in the rats and how melatonin helps :

https://www.sciencedirect.com/science/article/abs/pii/S0048969722072552?via=ihub

Here are some important highlights from the study :

• Rats were exposed to EMPs for 7 days and then subjected to ischemia followed reperfusion.
• EMPs are ingestion and accumulated in liver tissues in a size-dependent manner.
• EMPs triggered oxidative stress, autophagy, and inflammation in ischemic liver.
• Melatonin attenuated microplastic and ischemia-reperfusion toxicity.

This September 2023 study is very interesting in that it highlights the potential of melatonin and probiotics to work against the negative impact of MPs and further points out that MPs may be working through the gut brain axis :

https://pubmed.ncbi.nlm.nih.gov/37392641/

Here is an important quote from the paper :

' Both melatonin and probiotic can significantly reduce intestinal injury and restore the expression of circadian rhythm-related genes and neuroplasticity molecules, and the intervention effect of melatonin is more effective. Collectively, the results strongly suggest the gut-brain axis mediated hippocampal circadian rhythm changes involved in the neurotoxicity of PS-NPs. Melatonin or probiotics supplementation may have the application value in the prevention of neurotoxicity of PS-NPs. '

 In the following animal study it is shown melatonin alleviates intestinal barrier damaging effects from polyethylene (PE) MPs:

https://pmc.ncbi.nlm.nih.gov/articles/PMC10488227/

Here is an important revelation and quote from the study :

' Oral administration of PE-MP resulted in apparent jejunal histopathological alterations; significantly decreased mucin secretion, occludin, ZO-1, and claudin-1 expression; and significantly upregulated MLCK mRNA, IL-1β concentration, and cleaved caspase-3 expression. Melatonin reversed these altered parameters and improved the PE-MP-induced histopathological and ultrastructure changes. This study highlighted the PE-MP’s toxic effect on intestinal barrier integrity and revealed the protective effect of melatonin.

In the following mouse study it is shown how polystyrene (PS) MPs negatively impact mitochondrial function in mice and shows how melatonin offers protective effects :

https://pmc.ncbi.nlm.nih.gov/articles/PMC10664492/

Here is an important study quote :

' Our study demonstrated that PS-NPs disrupt mitochondrial function by affecting CI, leading to excessive mitophagy through the AMPK/ULK1 pathway, causing dopaminergic neuron death. Melatonin can counteract PS-NP-induced mitochondrial dysfunction and motor impairments by regulating mitochondrial autophagy. These findings offer novel insights into the MNP-induced PD-like neurodegenerative mechanisms, and highlight melatonin's protective potential in mitigating the MNP’s environmental risk.

This next study done in July 2024, shows how melatonin counteracts MPs induced adreno-cortical damage in rats :

https://www.sciencedirect.com/science/article/pii/S014765132400575X?via=ihub

Here are several important highlights from the study :

• The first study reports polyethylene microplastics-induced adrenal toxicity in rats.
• A reduction in serum cortisol and an increase in serum ACTH resulted from adreno-toxic effects of (PE)-MPs.
• PE-MPs inflammatory effect was illustrated by elevated expression of IL-1β and NF-ķB.
• Melatonin treatment was associated with a substantial amelioration of PE-MPs-induced toxic changes.

The following November 2024 study is important because it shows how melatonin may be able to alleviate the transgenerational effects of MPs on offspring of zebrafish :

https://www.sciencedirect.com/science/article/abs/pii/S0048969724061990?via=ihub

Here are some important highlights from the zebrafish study :

• Parental exposure to PSNP leads to growth inhibition of zebrafish larvae.
• PSNP induces oxidative stress, immunodeficiency and apoptosis in zebrafish offspring.
• MT has protective effect on intergenerational toxicity induced by PSNP.

This next study is important because it illustrates the lung damaging oxidative stress potential of MPs in rats and the multiple beneficial effects of melatonin in lungs :

https://pmc.ncbi.nlm.nih.gov/articles/PMC11672973/

Here is a very important and relevant quote from this animal study :

' Through metabolomic analysis, we expanded our understanding of the effects of prenatal PS-MPs exposure on toxicity in offspring lung tissues. Metabolomic analyses revealed that prenatal PS-MPs exposure caused significant oxidative stress and disrupted the nucleic acid metabolism and amino acid profiles in the lung tissues of seven-day-old rat pups. In addition, melatonin treatment significantly improved lung function in 120-day-old rats exposed to both prenatal and postnatal PS-MPs. These findings suggest that melatonin may be an effective therapeutic agent for mitigating lung damage caused by environmental pollutants, such as PS-MPs. Future studies should aim to validate these findings in humans, investigate the broader therapeutic mechanisms of melatonin, and establish effective clinical protocols to enhance its application in therapeutic settings. '

In the following June 2025 study it is shown that melatonin may work as a prenatal liver protectant in rat pups :

https://pmc.ncbi.nlm.nih.gov/articles/PMC12167250/

Here is a relevant study quote :

'  Results indicated that pups in the HFD-microplastics group (HFD-Mi) exhibited increased liver lipid accumulation (observed in histological staining), apoptosis (elevated cleaved caspase 3, phospho-AKT, and TUNEL staining), inflammation (higher IL- 6 and TNF-α), and oxidative stress (elevated malondialdehyde). Conversely, melatonin treatment (HFD-Mi + M) significantly reduced these effects, including lipid accumulation, apoptosis, and inflammation, while enhancing antioxidant enzyme glutathione peroxidase activity and improving lipid metabolism (reduced SREBP- 1 expression). These findings suggest that prenatal melatonin mitigates liver injury caused by maternal HFD and microplastics through its anti-inflammatory, antioxidative, and lipid-regulating properties, underscoring its potential hepatoprotective role. '

This July 2025 study is of significant importance because it illustrates how MPs can potentially exacerbate Alzheimer's disease (AD) in AD model mice :

https://www.sciencedirect.com/science/article/pii/S0147651325007158?via=ihub

Here are some important study highlights :

• Environmental relevant dose NPs exposure aggravated cognitive dysfunction in APP/PS1 mice.
• NPs exposure exacerbated Aβ plaque formation in APP/PS1 mice.
• NPs induced lysosomal damage and trigger pyroptosis in microglia, impairing their ability to clear Aβ plaques.
• Melatonin treatment ameliorated cognitive deficits and reduces Aβ plaque deposition caused by NPs exposure.

This September 2025 study is of significant importance as it discusses MPs and their potential impact on seizures and melatonin's role in ameliorating these effects :

https://www.sciencedirect.com/science/article/pii/S0147651325010863?via=ihub

Here are some relevant highlights from the study :

• Long-term microplastic exposure may affect independent risk factors of seizures, thereby exacerbating seizure symptoms.
• Long-term microplastic exposure may exacerbate seizure symptoms via the crosstalk between inflammation and ferroptosis.
• Long-term polystyrene microplastic exposure may exacerbate seizure symptoms in epileptic mice.
• Melatonin may alleviate the toxic effects of long-term polystyrene microplastic exposure in epileptic mice.

This final May 2025 study suggests melatonin as a potential remedy to ameliorate many negative health effects of MPs :

https://pmc.ncbi.nlm.nih.gov/articles/PMC12142344/

Here is a relevant study quote :

' Furthermore, this review highlights emerging attenuation strategies, including advanced filtration technologies, bioremediation approaches, and bioactive compounds such as melatonin, '

Conclusion

MPs have multiple negative effects on human health and research in this area is expanding at a rapid rate. Some of the known negatives of MPs in humans are :

1. Oxidative Stress

2. Inflammation

3. Lipid peroxidation

4. DNA Damage

5. Immune System Impairment

6. Metabolic Disorders

7. Neurotoxicity

8. Cardiovascular Disease

9. Gastrointestinal Issues

10. Liver Disease

Melatonin helps with all of the above and has a good safety profile. As would be expected, given the ability of melatonin to help alleviate the above 10 items in humans and animals, the above studies tend to confirm its potential as a readily available, inexpensive, safe and potentially effective remedy to help us deal with the negative effects of MPs. As seen in multiple animal studies, melatonin is often most effective when given prior to the "offending agent" used in studies to create a negative health condition. In other words, melatonin is generally most effective before the problem becomes evident and likely works best a a preventative agent.

Additional Supplements for Microplastic Detoxing

Given some of the known pathways in which MPs work, other potential supplements that are likely to be useful in mitigating the negative health effects of MPs are :

1. Astaxanthin                                        11. Activated Charcoal

2. NAC                                                   12. Probiotics

3. Quercetin                                           13. Omega 3s

4. Vitamin D                                           14. Vitamin C

5. EGCG                                                15. Vitamin E

6. Curcumin                                           16. Resveratrol

7. Selenium                                            17. Green Tea Extract

8. Alpha Lipoic Acid                                18. Sulforaphane (From Broccoli Sprouts)

9. Zeolite                                                 19. Bentonite Clay

10. Silymarin                                            20. Apple Pectin

::::::::::::::::::::::::::::::::::::::

Art