How do microplastics end up in your skincare products if they're not listed as ingredients?
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Ingredient labels list what manufacturers intentionally added to a product. Microplastics introduced through plastic packaging, manufacturing equipment, or the production environment are contaminants, not ingredients, and no U.S. or EU regulation currently requires them to appear on any label.
Scientific evidence suggest there are at least two contamination pathways: (1) plastic packaging, which can shed microplastics at rates that increase with heat, contact time, and formulation chemistry; and (2) manufacturing equipment, which often utilize filling nozzles, plastic tubing, gaskets, and heat-sealing machinery.
Why labels don't show this
Ingredient labels only cover what a brand intentionally adds to a product. Meanwhile, microplastics that enter through plastic packaging or manufacturing equipment are contaminants. The Microbead-Free Waters Act (2015) banned intentionally added microbeads in rinse-off products, but leave-on products like moisturizers, night creams, and sunscreens aren't covered, and contamination isn't addressed at all.
How packaging introduces microplastics
Plastic packaging (PET bottles, PP jars and caps) can shed particles into the product it contains during normal storage and use. Several factors can accelerate this:
- Formulation chemistry: Alcohols, acids, and essential oils commonly found in skincare can react with plastic packaging, degrading the polymer matrix and increasing particle release. A 2024 critical review published in the Journal of Hazardous Materials by researchers at the University of Birmingham specifically identified this interaction as a factor in cosmetics.
- Temperature: Heat accelerates polymer degradation. Products stored in bathrooms, shipping containers, or vehicles can experience repeated heat exposure over their shelf life.
- Mechanical stress: Pumping, squeezing, and cap opening can introduce abrasion that releases particles. Studies on bottled beverages show microplastic counts increase with each open/close cycle.
- Time: Cumulative leaching increases with storage duration.
The food and beverage literature provides the strongest available data on leaching, given the limited cosmetics-specific research. Microplastics have been detected in virtually all bottled beverages tested, and leaching occurs during normal use, not only under stress conditions.
How manufacturing equipment introduces microplastics
A 2026 review published in RSC Sustainable Food Technology documented microplastic contamination from the equipment used to fill and seal packaged products. It identified the following as possible sources of contamination:
- Tube fillers and filling nozzles: polymer gaskets and nozzles in frictional contact with machine components generate particles through abrasion. The polymer types most commonly identified in filling operations (PP, PET, and PVC) are consistent with the materials used in these components.
- Plastic tubing: used to move formulations between mixing tanks and filling stations; inner surfaces shed particles into product flow, particularly under pressure.
- Gaskets, seals, and O-rings: polymer-based components in pumps and valves degrade over time, with chemical exposure from formulation ingredients accelerating the process.
- Heat-sealing equipment: used to apply foil seals and tamper-evident packaging; generates particles when films are softened by heat and exposed to mechanical force.
This review was conducted on food processing equipment; however, the mechanism is identical in cosmetic manufacturing. Microplastic contamination can reach finished product even in facilities that do not use plastic as primary packaging.
The research gap
Despite these documented pathways, leave-on cosmetics (e.g., moisturizers, night creams, serums) are almost entirely absent from the scientific literature on microplastic contamination.
The 2024 University of Birmingham critical review analyzed 2,381 cosmetic products studied in the peer-reviewed literature. Of those, only two were leave-on products. The researchers called for urgent investigation.
A February 2026 study published in MDPI Cosmetics directly detected and quantified microplastics in 21 skincare and treatment cream samples and noted that contamination from processing and packaging "cannot be ruled out" as sources. No peer-reviewed study has yet systematically measured incidental microplastic concentrations in moisturizers and night creams across brands.
What you can do with this
There's currently no way to know from a label whether a specific skincare product contains microplastic contamination from its packaging or manufacturing.
At KnowLabels, we test skincare products for microplastics, including contamination from packaging and manufacturing. Join our waitlist to learn more about what you are putting in your skin.
Frequently asked questions
If microplastics aren't listed as an ingredient, can they still be in my moisturizer?
Yes. Ingredient lists reflect intentional additions. Microplastics introduced through plastic packaging, manufacturing equipment, or the production environment are contaminants, not ingredients, and no current US regulation requires them to be disclosed on a label.
How do microplastics get into skincare products through packaging?
Plastic packaging sheds particles into the product it contains. The rate is influenced by formulation chemistry (alcohols and acids in skincare can accelerate polymer degradation), temperature, mechanical stress from opening and dispensing, and storage duration. These are routine aspects of normal skincare use and storage.
Does manufacturing equipment add microplastics to skincare products?
Based on current evidence from the food processing literature, yes. A 2026 review documented microplastic generation from filling nozzles, plastic tubing, gaskets, and heat-sealing equipment used in packaged product manufacturing. The dominant polymer types found, PP and PE, match the materials used in this equipment. The research was conducted on food processing equipment, which is functionally equivalent to cosmetic manufacturing equipment.
Are brands required to test their moisturizers for microplastic contamination?
No. In the US, there is no requirement to test for or disclose incidental microplastic contamination in any cosmetic product.
Have microplastics actually been detected in moisturizers?
A 2026 study published in MDPI Cosmetics detected and quantified microplastics in 21 skincare and treatment cream samples, noting that packaging and manufacturing contamination "cannot be ruled out" as sources. Leave-on cosmetics remain critically understudied: of 2,381 cosmetic products analyzed across the peer-reviewed literature in a 2024 University of Birmingham review, only two were leave-on products.
Sources
- Beyond microbeads: examining the role of cosmetics in microplastic pollution (University of Birmingham, Journal of Hazardous Materials, 2024) — ScienceDirect / University of Birmingham coverage
- Microplastic release from food processing to the environment (RSC Sustainable Food Technology, 2026) — RSC Publishing
- Identification, quantification, and characterization of microplastics in skincare and treatment creams (MDPI Cosmetics, February 2026) — MDPI
- Microplastics in packaged beverages — metal cap coatings as primary source (ANSES, Journal of Food Composition and Analysis, 2025) — phys.org coverage / Technology Networks coverage