10 Worst Ingredients for Microplastics (and How to Spot Them)

The Hidden Plastics in Your Everyday Products

When most people hear the word "microplastics," they picture tiny fragments floating in the ocean or washing up on beaches. What they do not realize is that millions of consumer products -- from moisturizers and foundations to sunscreens and shampoos -- contain intentionally added microplastic ingredients. These are not contaminants that accidentally ended up in the formula. They are deliberately included by manufacturers to serve specific functions like thickening, smoothing, film-forming, and exfoliating.

The problem is that these synthetic polymer ingredients are rarely labeled in any way that a typical consumer would recognize as "plastic." Instead, they hide behind long chemical names that most people skim right over. A 2021 study by the Plastic Soup Foundation found that up to 90% of cosmetic products sold in major retail chains contained at least one microplastic ingredient. That means nearly every product in your bathroom cabinet could be introducing plastic particles into your body through your skin, your lungs, or your digestive system.

In this guide, we break down the 10 worst microplastic ingredients found in consumer products today. For each one, you will learn what it is, where it is commonly found, what the health concerns are, and exactly what to look for on ingredient labels. If you have already read our guide on microplastics in cosmetics, this article goes deeper into the specific chemical culprits behind the contamination.

1. Polyethylene (PE)

What It Is

Polyethylene is the most widely produced plastic in the world, and it is also the single most common microplastic ingredient found in consumer products. In personal care formulations, it appears as tiny beads, powders, or wax-like substances used for exfoliation, texture, and moisture retention. It is the same polymer used to make plastic bags, bottles, and packaging film, just ground down to microscopic size.

Where It Is Found

Exfoliating face washes and body scrubs are the most well-known sources, but polyethylene also appears in toothpastes, lip balms, mascaras, eyeliners, foundations, hair styling products, and even some sunscreens. It is one of the most versatile cosmetic ingredients because manufacturers can control its particle size, shape, and texture to fit virtually any product type.

Health Concerns

Polyethylene microbeads do not dissolve or break down in water. When you rinse them off your skin, they pass through wastewater treatment systems and enter rivers, lakes, and oceans, where they are ingested by marine life and eventually work their way back into the food chain. On the skin itself, microscopic polyethylene particles can penetrate pores and cause irritation. Studies have shown that PE particles can absorb environmental toxins like heavy metals and pesticides, potentially delivering concentrated pollutants into your body.

What to Look for on Labels

Look for "Polyethylene," "PE," "Polyethylene Glycol" (different but related), or "Polyethylene Microspheres." Some products list it as "Polyethylene Powder" or "Polyethylene Beads."

2. Polypropylene (PP)

What It Is

Polypropylene is the second most commonly produced plastic globally, widely used in food packaging, textiles, and automotive parts. In cosmetics and personal care products, it functions as a bulking agent, absorbent, and skin-conditioning additive. Like polyethylene, it is a synthetic thermoplastic polymer derived from petroleum.

Where It Is Found

Polypropylene appears frequently in lipsticks, lip glosses, foundations, concealers, blush, eyeshadow, and skin care creams. It is particularly common in lip products because it creates a smooth, waxy texture that helps formulas glide on evenly. It is also found in some baby care products and sunscreens.

Health Concerns

Polypropylene is considered chemically stable, but that stability is exactly the problem: it does not biodegrade. Once in the environment or in your body, PP particles persist indefinitely. In lip products, polypropylene is repeatedly ingested in small amounts every time you eat, drink, or lick your lips. Over the course of a year, studies estimate that a regular lipstick user may ingest several grams of product, including whatever plastic polymers it contains.

What to Look for on Labels

Search for "Polypropylene," "PP," or "Polypropylene Powder."

3. Polymethyl Methacrylate (PMMA)

What It Is

Polymethyl methacrylate is a transparent thermoplastic often used as a lightweight alternative to glass, known commercially as Plexiglas or acrylic glass. In cosmetics, PMMA is ground into ultra-fine microspheres that scatter light, creating a "soft focus" effect that makes skin appear smoother and more even. It is essentially powdered acrylic plastic.

Where It Is Found

PMMA is common in foundations, primers, anti-aging creams, nail polishes, and pressed powders. It is a staple ingredient in products marketed as "blurring," "smoothing," or "pore-minimizing." You will also find it in some dermal fillers and dental products, though those are medical-grade formulations with different regulations.

Health Concerns

PMMA microspheres are small enough to penetrate skin pores and accumulate in tissue. Research has raised concerns about potential inflammatory responses when PMMA particles lodge in the skin or are inhaled as part of pressed powder application. Like all synthetic polymers, PMMA does not biodegrade and persists in the body and environment indefinitely.

What to Look for on Labels

Look for "Polymethyl Methacrylate," "PMMA," "Methyl Methacrylate Crosspolymer," or "Acrylate/Methyl Methacrylate Copolymer."

4. Nylon-12 (Polyamide)

What It Is

Nylon-12, also known as Polyamide-12, is a synthetic polymer from the nylon family. In cosmetics, it is used as a bulking agent, slip modifier, and absorbent. It creates a silky, smooth texture in powder-based products and helps formulations adhere to the skin. Nylon is the same material used to make stockings, rope, and industrial components, just processed into a fine cosmetic-grade powder.

Where It Is Found

Nylon-12 is prevalent in pressed powders, foundations, mascaras, eyeshadows, blush, bronzers, and mattifying products. It is especially common in products designed to control oil and shine, as nylon particles absorb excess sebum. It also appears in some deodorants and body powders.

Health Concerns

As an inhalable microplastic, nylon-12 raises particular concerns in loose powder and spray products. When you apply pressed powder with a brush or puff, fine nylon particles can become airborne and enter the lungs. Inhalation of synthetic polymer particles has been linked to respiratory irritation and potential long-term lung tissue damage. Like other microplastics, nylon-12 does not biodegrade.

What to Look for on Labels

Look for "Nylon-12," "Polyamide-12," "Nylon-6," "Nylon-66," or simply "Nylon" followed by a number.

5. Polyethylene Terephthalate (PET)

What It Is

PET is the same plastic used in soda bottles and food packaging. In cosmetics, it is the primary material behind most cosmetic glitter and shimmer effects. PET is processed into thin, reflective flakes or films that create sparkle in eyeshadows, body glitter, highlighters, and nail polishes. It is one of the most persistent plastics in the environment.

Where It Is Found

Any product with glitter, shimmer, or metallic effects almost certainly contains PET unless it specifically advertises biodegradable or mineral-based alternatives. This includes eyeshadow palettes, body shimmer sprays, glitter nail polishes, face glitter, highlighters, and even some children's craft products. PET is also used in some hair products for shine.

Health Concerns

PET can leach antimony, a toxic metalloid, especially when exposed to heat or UV light. PET glitter particles are sharp-edged and can cause micro-abrasions on the skin and eyes. When washed off, these particles are too small for most water treatment plants to capture, making cosmetic glitter one of the most significant contributors to environmental microplastic pollution. Research has detected PET particles in human blood, placental tissue, and lung tissue.

What to Look for on Labels

Look for "Polyethylene Terephthalate," "PET," "PETE," or the generic term "Glitter" (which is PET unless stated otherwise).

6. Acrylates Copolymer

What It Is

Acrylates copolymer is a broad family of synthetic polymers used as film-forming agents, binders, and hair fixatives in cosmetic formulations. These polymers create a thin plastic film on the skin or hair that provides hold, water resistance, or a smooth finish. Despite their liquid or gel-like appearance in products, acrylates copolymers are synthetic plastics in every chemical sense.

Where It Is Found

This is one of the most ubiquitous microplastic ingredients in the personal care industry. Acrylates copolymers appear in sunscreens (for water resistance), hair sprays and gels (for hold), mascaras (for waterproofing), nail polishes, foundations, primers, and even some moisturizers. If a product claims to be "long-lasting," "waterproof," or "transfer-resistant," there is a high probability it contains acrylates copolymer.

Health Concerns

Acrylates copolymers can cause skin sensitization and allergic contact dermatitis in some individuals. Because they form a film over the skin, they can trap other chemicals against the skin surface, potentially increasing the absorption of other harmful ingredients. When washed off, they contribute to microplastic pollution in waterways. The residual monomers (unreacted building blocks) in acrylate polymers are known irritants and potential carcinogens.

What to Look for on Labels

Look for "Acrylates Copolymer," "Acrylates/C10-30 Alkyl Acrylate Crosspolymer," "Acrylates/Steareth-20 Methacrylate Copolymer," "Ethyl Acrylate," or any ingredient containing the word "acrylate" or "acrylates."

7. Polyurethane

What It Is

Polyurethane is a versatile synthetic polymer used across dozens of industries, from furniture foam to automotive coatings. In personal care products, polyurethane serves as a film-forming agent and binding ingredient. It creates a flexible, durable coating that helps products adhere to skin and hair. It is the same class of plastic used in spray-on coatings, adhesives, and synthetic leather.

Where It Is Found

Polyurethane is commonly found in hair styling products (gels, mousses, and sprays), nail polishes and nail hardeners, waterproof mascaras, self-tanning products, and some anti-aging serums that promise a "tightening" or "lifting" effect. The "hold" you feel from a hair gel or the rigid coating of a nail polish is often polyurethane at work.

Health Concerns

Polyurethane is manufactured using diisocyanates, which are potent respiratory sensitizers and known occupational hazards. While the finished polymer is more stable, degradation and heat exposure can release isocyanate compounds. Polyurethane coatings on the skin prevent natural transpiration and can trap bacteria, potentially causing skin irritation. In nail products, prolonged exposure to polyurethane-based formulas has been associated with nail bed damage and allergic reactions.

What to Look for on Labels

Look for "Polyurethane," "PUR," "Polyurethane-14," "Polyurethane-34," or any ingredient with "Polyurethane" followed by a number.

8. Carbomer

What It Is

Carbomer is a family of synthetic polymers made from polyacrylic acid. It functions primarily as a thickening agent and emulsion stabilizer, giving gels, creams, and lotions their characteristic smooth, thick texture. While many people do not think of carbomer as a "plastic," it is a fully synthetic polymer derived from petroleum-based chemicals. Carbomers are crosslinked polyacrylic acids that form a three-dimensional polymer network, and they do not biodegrade in the environment.

Where It Is Found

Carbomer is one of the most widely used ingredients in the entire personal care industry. It appears in moisturizers, face gels, hand sanitizers, hair gels, eye creams, serums, toothpaste, shaving gels, body lotions, and pharmaceutical gels. Almost any product with a gel-like or creamy smooth consistency likely contains a carbomer. It is also extensively used in hand sanitizer formulations, meaning global usage spiked dramatically during and after 2020.

Health Concerns

Carbomers themselves have low acute toxicity, which is why they have been so widely adopted. However, the microplastic concern stems from their synthetic polymer nature: carbomers do not break down in wastewater or the environment, contributing to the growing burden of polymer pollution. Additionally, carbomers can contain residual benzene (a known carcinogen) from the manufacturing process. Some individuals also experience skin irritation or allergic reactions to carbomer-containing products, particularly at higher concentrations.

What to Look for on Labels

Look for "Carbomer," "Carbomer 934," "Carbomer 940," "Carbomer 941," "Carbomer Homopolymer," or "Carbopol." The number following "Carbomer" indicates the specific grade, but all are synthetic polyacrylic acid polymers.

9. Polylactic Acid (PLA)

What It Is

Polylactic acid is a synthetic polymer derived from fermented plant starches, typically corn or sugarcane. It is heavily marketed as a "biodegradable" or "plant-based" plastic and has become the poster child for the "eco-friendly plastics" movement. PLA is used in packaging, disposable cutlery, 3D printing, and increasingly in cosmetic and personal care products. However, the "biodegradable" label is deeply misleading.

Where It Is Found

PLA appears in some "eco-friendly" personal care products, biodegradable glitter alternatives, green-branded packaging, exfoliating scrubs marketed as sustainable, and increasingly in cosmetic sheet masks and single-use applicators. It is also found in tea bags, food containers, and disposable cups marketed as compostable.

Health Concerns

Here is the uncomfortable truth about PLA: it only biodegrades under very specific industrial composting conditions, namely sustained temperatures above 140 degrees Fahrenheit (60 degrees Celsius) with specific moisture levels and microbial activity. In a landfill, in the ocean, in a home compost bin, or in your body, PLA behaves exactly like any other plastic. It does not break down. A 2023 study published in Environmental Science and Technology confirmed that PLA fragments into microplastics in marine environments just like conventional petroleum-based plastics. So while PLA may have a greener origin story, its end-of-life behavior is functionally identical to traditional microplastics.

What to Look for on Labels

Look for "Polylactic Acid," "PLA," "Polylactide," or marketing terms like "plant-based plastic," "corn-based polymer," or "biodegradable plastic." Be skeptical of any product that claims its plastic components are biodegradable without specifying industrial composting conditions.

10. Dimethicone / Silicones

What It Is

Dimethicone is the most common silicone used in cosmetics and personal care. Silicones are synthetic polymers made from silicon, oxygen, carbon, and hydrogen. While technically not "plastics" in the traditional carbon-chain sense, silicones are classified as synthetic polymers and are increasingly grouped with microplastics by environmental researchers and regulators. The European Chemicals Agency (ECHA) includes certain silicones in its microplastic restriction proposals. Dimethicone creates a slippery, silky feel and forms a waterproof barrier on skin and hair.

Where It Is Found

Dimethicone and related silicones are among the most pervasive cosmetic ingredients on the market. They appear in shampoos, conditioners, leave-in hair treatments, foundations, primers, moisturizers, sunscreens, BB creams, CC creams, anti-frizz serums, body lotions, deodorants, and shaving creams. Virtually any product that claims to be "smoothing," "silky," or "hydrating" likely relies on silicone polymers.

Health Concerns

Dimethicone forms an occlusive barrier on the skin that can trap dirt, bacteria, sebum, and other chemicals underneath, potentially leading to clogged pores, breakouts, and increased absorption of other harmful ingredients. On hair, silicone buildup can cause dryness, breakage, and scalp irritation over time. Environmentally, silicones are persistent pollutants. They do not biodegrade in water and accumulate in aquatic sediments, where they have been shown to affect marine organisms. Cyclic silicones like cyclomethicone (D4 and D5) are classified as endocrine disruptors by the EU and have been restricted in wash-off cosmetics in Europe.

What to Look for on Labels

Look for "Dimethicone," "Cyclomethicone," "Cyclopentasiloxane," "Dimethiconol," "Phenyl Trimethicone," "Amodimethicone," or any ingredient ending in "-cone," "-conol," or "-siloxane." The "-cone" suffix is the quickest way to identify silicone ingredients.

How to Read Labels Like a Microplastics Expert

Now that you know the 10 worst offenders, here is a practical system for reading any product label and identifying microplastic ingredients quickly:

1. Look for the "poly-" prefix. Any ingredient that starts with "poly" is a polymer. While not every polymer is a microplastic, this prefix is your fastest filter. Polyethylene, polypropylene, polymethyl methacrylate, polyurethane, polylactic acid -- they all start with "poly."
2. Watch for the "-copolymer" suffix. Ingredients ending in "copolymer" are synthetic polymers made from two or more monomer types. Acrylates copolymer, VP/VA copolymer, and styrene/acrylates copolymer are all microplastic ingredients.
3. Check for "-cone" and "-siloxane" endings. These indicate silicone-based synthetic polymers. Dimethicone, cyclomethicone, and cyclopentasiloxane are the most common.
4. Beware of "nylon" in any form. Nylon-6, Nylon-12, Nylon-66, and Polyamide are all synthetic microplastic ingredients regardless of the number attached.
5. Understand ingredient order. Ingredients are listed in descending order of concentration. If a microplastic ingredient appears in the first half of the list, the product contains a significant amount. If it appears in the last third, the concentration is lower but still present.
6. Be skeptical of marketing claims. Terms like "natural," "clean," "green," and "eco-friendly" are unregulated. A product can use these terms on its packaging while containing multiple synthetic polymer ingredients. Always read the actual ingredient list, not the front label.

Quick Reference: Red Flag Keywords

Skip the Guesswork: Let the MicroPlastics App Do It for You

Reading ingredient labels is a valuable skill, but it is also time-consuming and error-prone. Chemical names are confusing, manufacturers frequently change formulations, and new synthetic polymers are introduced regularly. Even experienced label readers can miss hidden microplastic ingredients, especially when they appear under unfamiliar trade names or in complex multi-word chemical designations.

The MicroPlastics app eliminates this entire problem. Simply scan a product barcode with your phone camera or search by product name, and the app instantly analyzes every ingredient against a comprehensive database of known microplastic and synthetic polymer compounds. Within seconds, you receive a clear safety score from A (safest) to F (highest concern), along with a detailed breakdown of exactly which ingredients are flagged and why.

The app catches ingredients that even careful label readers might miss, including polymers listed under obscure trade names, newly introduced synthetic compounds, and ingredients that are technically microplastics but rarely discussed in mainstream consumer guides. It also tracks your cumulative microplastic exposure over time, helping you see the real-world impact of switching to cleaner products.

For a step-by-step walkthrough of how to use the app, including barcode scanning, product search, and exposure tracking, check out our complete guide to checking products for microplastics.

Take Control of What Goes on and in Your Body

The 10 ingredients covered in this guide represent the most common and most concerning microplastic compounds hiding in everyday consumer products. From the polyethylene beads in your face wash to the dimethicone in your hair conditioner, synthetic polymers are woven into nearly every product category on the market. Manufacturers add them because they are cheap, effective, and consumers rarely question their presence.

But now you know what to look for. You know the chemical names. You know the label patterns. And you know that tools like the MicroPlastics app can automate the detection process entirely, giving you instant clarity about any product before it touches your skin or enters your home.

You do not need to overhaul your entire routine overnight. Start by checking the products you use most frequently -- your daily moisturizer, your shampoo, your toothpaste, your foundation. Replace the worst offenders first and work outward from there. Every product you swap for a cleaner alternative is one less source of microplastic exposure for you and your family.

Download the MicroPlastics app today and scan the products in your bathroom. The ingredients you cannot pronounce might be the ones you should worry about most.