Often, cosmetic and personal care formulations incorporate a wide variety of polymers, including natural polymers, synthetic organic polymers, and silicones [1]. These materials perform multiple functions, such as acting as film formers, emulsifiers, thickeners, texture modifiers, protective barriers, and aesthetic enhancers (Table 1). In particular, polymers are widely used as rheology modifiers in water-based formulations, which typically exhibit low viscosity.

To increase viscosity or form gels, formulators commonly rely on natural polymers such as polysaccharides, starches, xanthan gum, guar gum, carrageenan, alginates, pectins, gelatin, and agar. Many of these natural polymers are chemically modified to improve their suitability for cosmetic applications, as exemplified by cellulose derivatives including hydroxyethylcellulose, methylcellulose, and hydroxypropylcellulose. In parallel, a range of synthetic polymers—such as polyacrylic acid and its derivatives (carbomers), polyacrylamides, and alkylene oxide–based homo- and copolymers—are frequently employed due to their functional versatility.

Also, in hair conditioning products, both natural and synthetic polymers are used to enhance texture, manageability, and performance. Natural polymers include hydrolyzed proteins, cellulose-based polysaccharides, and gums such as gum arabic and gum tragacanth, while commonly used synthetic polymers include polyvinylpyrrolidone, polyvinyl acetate, polyacrylates, polymethacrylates, polyvinylamides, polyurethanes, and silicones [2][3].

Polyurethanes, in particular, are widely applied in both solvent-based and aqueous cosmetic systems. Solvent-based polyurethanes are frequently used as secondary film formers in nail products, whereas waterborne polyurethanes are commonly found in mascaras and skin care formulations [4].

Importantly, water-soluble functional polymers are polymers that dissolve completely in water to form true solutions. In cosmetic formulations, they are used to provide functions such as thickening, film formation, conditioning, or stabilization. Because they are dissolved at the molecular level, they do not exist as discrete solid particles and are not considered particulate matter in the environment. These polymers are not part of this review.

In contrast, a number of personal care and cosmetic product (PCCP) formulations contain solid, synthetic polymer particles in the micro- or submicron size range. They can be made of polyolefins (polythene, polypropylene and polyisopropylene), polystyrene, polyesters, polyamides (nylons), or similar polymers. These materials serve multiple functions, including acting as abrasives for exfoliation, smoothing, and polishing of the skin; as delivery systems for active ingredients; and as carriers of colorants. In addition, submicron polymer powders may be used for thickening, bulking, or modifying the sensory properties of products (Table 1). Due to their small size and solid polymeric nature, these materials are classified as plastics, specifically microplastics (MPs). In PCCPs, they are most commonly incorporated in the form of microbeads and as powdered material/particulate matter.

Table 1. A list of polymer types found in PCCPs along with their common uses/purpose (AACO = aromatic polyalkene co-polymer, APH= aromatic polyhydrocarbons), E = polyester, PA = polyalkene, ECO = ester co-polymer; PFA = polyfluoroalkene, Si = polysiloxane (silicone), U = polyurethane).

Plastics are ubiquitous in modern society. The term “plastic” refers to polymeric materials that soften upon heating and can be molded into solid forms [5]. This category includes both virgin plastic pellets used in manufacturing and polymer resins blended with additives to enhance material performance [5]. Global plastic production has increased dramatically, rising from approximately 1.7 million metric tons in the early years of mass production during the 1940s and 1950s to 335, 400.4, 413.8, and 443.5 million metric tons in 2016, 2022, 2023, and the projected value for 2025, respectively [6]-[9]. This corresponds to an average annual growth rate of about 3.5% in recent decades. Plastic production is expected to reach approximately 1.12 billion metric tons by 2050 [10].

To date, an estimated 8,300 million metric tons of virgin plastic materials have been produced globally. By 2015, of the 6,300 million metric tons of plastic waste generated, only about 9% were recycled, 12% incinerated, and 79% accumulated in landfills or released into the natural environment [11][12]. If current production and waste management trends persist, plastic waste in landfills and the environment is projected to reach roughly 12,000 million metric tons by 2050 [11].

Once released into the environment, plastics persist for long periods of time. Most commonly used plastics are non-biodegradable and degrade primarily through abiotic processes such as through thermal oxidation [13], UV-driven photo-oxidation [14][15], and hydrolysis [16], often combined with mechanical weathering [17]. These processes occur slowly, resulting in very long environmental half-lives [18]. The widespread and persistent presence of plastic debris has even been proposed as a geological marker of the Anthropocene epoch [19].

Plastics are commonly classified by particle size into macroplastics (> 10 mm), mesoplastics (5 - 10 mm), and microplastics (< 5 mm) [20]. The term “microplastics” was first introduced by Thompson et al. [21]. More recently, the term “nanoplastics” has been proposed, with some authors defining nanoplastics as particles ≤ 100 nm [22], while others suggest an upper boundary for nanoplastics of ≤ 1 µm [23][24].

Microplastics and nanoplastics can originate from the fragmentation of larger plastic debris; however, they are also intentionally manufactured for specific applications. These intentionally produced particles are referred to as primary microplastics and nanoplastics [25][26]. Major sources of primary microplastics include cosmetics [25], pharmaceuticals [27], textiles [28][29], and sandblasting materials [30].

A substantial proportion of microplastics from these sources enters wastewater systems and is transported to wastewater treatment plants [31]. Although treatment plants retain a large fraction of microplastics in sewage sludge [32], some particles escape removal, leading to the classification of wastewater treatment plants as point sources of microplastic pollution in aquatic environments [33]. Additional sources include accidental spills of virgin plastic pellets during loading and off-loading operations and during maritime transport [34][35].

Once in marine environments, microplastics can be ingested by aquatic organisms [36], some of which are subsequently consumed by humans as seafood [37][38]. As a result, microplastics have now been detected in all major human organs [39]. While the potential health impacts of microplastics have long been suspected [40], recent studies have begun to establish clearer associations between microplastic exposure and specific health outcomes, including osteoporosis [41].

Although personal care and cosmetic products contribute a relatively small proportion of total plastic emissions—estimated at 0.1% - 4.1% depending on the study [28][42][43]—they represent a category of primary microplastics that can be effectively reduced through regulation. Plastic MBs used in PCCPs have therefore received particular attention. Their relevance is amplified by direct human exposure, including oral ingestion in products such as toothpaste [44]. Regulatory attention intensified with the U.S. Microbead-Free Waters Act of 2015 [45], which prohibited the manufacture and sale of rinse-off cosmetics containing plastic MBs. Other regions followed suit, as will be discussed below.

Historically, the most commonly used polymers in plastic MBs have included polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), poly (methyl methacrylate) (PMMA), and nylon. However, not all MBs used in PCCPs are synthetic. Natural and biodegradable alternatives—such as cellulose, cornmeal, apricot kernels, walnut husks, and pumice—have been used thoughout and are now widely employed as abrasives, bulking agents, opacifiers, and microbead substitutes [46]-[48]. Table 2 presents a selection of natural materials either used concurrently to plastic microbeads/particulates or instead of these as abrasives/polishing agents in cosmetic formulations.

Table 2.Common natural abrasives used in cosmetics. (see also: [49])

In the last decades, the percentage of MBs in the composition of PCCPs depended on whether the products were rinse-off or leave-off [50], where historically the percentage of MBs in the products differed widely and ranged from less than 1% to more than 90% [51]. It is important to note that MBs play a vital role in some of the cosmetics products. Their functions depend on their size, shape as well as composition [50]. While, as stated above, polymers in cosmetics are used as binders, bulking agents, emulsifiers, film formers, viscosity regulators, opacifying agents, glitter additives, skin conditioners, tooth polishers in oral care, gellants in denture adhesives, moisturizers, UV filters, and stabilizers (see Table 1 [52][53]), only in some of the uses are the polymers used in form of actual plastic MBs. The focus of much of the literature is on the use of plastic MBs as exfoliants [54]-[56], especially in body and facial scrubs, shower gels and toothpastes. Oftentimes, here, the basic function of the MBs is to produce a smoother skin by increasing the rate of keratinization through exfoliation [57]-[59]. Abrasive scrubs can incorporate both natural and synthetic materials at the same time [60] to induce various degrees of exfoliation [61]. As we will see, the composition of abrasive material in PCCPs has changed over time, beginning with exclusively natural material, then, with the advent of synthetic polymers incorporating plastic MPs and currently experiencing a policy driven phase out of such plastic MBs. This contribution aims to outline the historical development of microplastic-containing PCCPs, including an examination of patent trends over time, and to trace the gradual elimination of these materials from such products in light of the evolving understanding of the potential human health impacts of microplastics from cosmetics. In addition, the article explores the search for alternative materials to replace MBs in cosmetic formulations.

To date, a number of reviews on different aspects of MPs in cosmetics have appeared in form of journal articles [52][56][62]-[69] and of book chapters [70]-[72] including on new developments in biodegradable MBs [52][73][74] and on health implications of MPs in cosmetics [68][69][72]. For the current review, the databases Scopus®, SciFinder® and Web of Science® as well as the search engines google search® and google scholar® were utilized. Key word combinations such as “microplastics AND cosmetics”, “microbeads AND cosmetics”, “microplastics AND toothpastes”, “microbeads AND toothpastes”, “microplastics AND personal care products”, “microbeads AND personal care products” were used in the searches. For exclusion/inclusion of the articles, first the titles and then the abstracts of the respective papers were evaluated. References cited by the chosen articles were scrutinized as to their relevancy as were all the manuscripts that were listed in the citation index of the chosen articles. For the patent search, keyword combinations such as “polythene/polyethylene AND cosmetics” and “plastic AND cosmetics” were used, covering the period from 1959 to the present. The database SciFinder® was used to search for patents published on MPs in PCCPs. Patents were viewed through PatentPak® as embedded in SciFinder®. Furthermore, copies of some of the patents were obtained through the search engine google patents® (https://patents.google.com), through Espacenet® (https://worldwide.espacenet.com/patent/) as well as through Justia® patents (https://patents.justia.com/). Also, the webpage https://www.epo.org/en/searching-for-patents/technical/publication-server was used to receive access to copies of European patents. Journal articles were mostly acquired through the UAEU electronic library. In the review, the collection of patents on plastic microbeads and microspheres and their substitutes in cosmetic formulations is intended to be illustrative and is not exhaustive. Thus, while some of the patents are seminal in the field, other patents are chosen to be representative of a larger body of similar patents.

Various polymers used in cosmetics are either water-soluble or incorporated in emulsions without forming solid microplastics (MPs). Although reference is given to them, these types of polymers are largely excluded from the scope of this review. Additionally, the review does not address inadvertently added MPs, such as those resulting from the degradation of cosmetic plastic packaging—e.g., MPs generated when opening the plastic lid [75] to a packaged PCCP. It also does not cover MPs formed during the manufacturing or recycling processes of such packaging, although these have become a focus of emerging government regulations [76]-[79].

Facial cosmetics have been a part of human culture for millennia, and recent studies suggest that Homo sapiens may not be the only humanoid species to have used body ornamentation. Evidence indicates that even Neanderthals (Homo sapiens neanderthalensis) might have utilized mineral-based pigments, such as hematite (Fe₂O₃), goethite [α-Fe(O)OH], and pyrite (FeS₂), for decorative or ritual purposes [80].

In more recent history, the use of cosmetics is well-documented, not only through archaeological discoveries but also in written texts. One notable example is the Roman poet Ovid (43 BC - 17 AD), who composed a poem titled Medicamina faciei femineae, which includes four complete recipes and one fragmentary recipe for topical facial applications [81]. These ancient formulations, much like today’s facial cleansers, featured a balance of liquid or oily bases with solid ingredients—both organic and inorganic. These solids performed functions similar to those of modern facial products, such as exfoliation and cleansing. Notable ingredients in Ovid’s recipes included salts like Libyan Desert salt (sal ammoniacum), natron, and red natron (sodium carbonate hydrate with cyanobacteria such as Spirulina, giving it a reddish hue). Also included were ground oyster shells, chalk dust, and Melos clay [81][82]. Organic abrasives like ground charcoal, deer antlers, and spelt (Dinkel wheat) were also used. The intended effects of these formulations were to remove makeup, lighten the skin, smooth the complexion, and conceal blemishes—goals that remain central to modern cosmetic products.

Alongside these early cleansers, the use of pigments in facial cosmetics became more diversified. The black pigment kohl, traditionally made from ground stibnite (Sb₂S₃), and the brilliant red vermilion made from ground cinnabar (HgS) were widely used. Other pigments, such as red lead tetroxide (Pb₃O₄) and white ceruse (2PbCO₃·Pb(OH)₂), were common in certain social circles from the Renaissance through the 18th century. By the 19th century, zinc oxide began replacing white ceruse as the preferred face powder. Organic dyes were also used, with substances like alkanet (from Alkanna tinctoria) and the red-orange dye from safflower (Carthamus tinctorius) being favored. In the section below, we will see that for many years from the late 1970s to the 2020s the colors of many body scrubs, body shampoos and toothpastes were imparted by colored MBs, where metal phthalocyanins such as phthalocyanins green and blue, triphenylmethane dyes such as brilliant blue FCF, or azo-organic substances such as pigment red 5 were often involved.

Turning back to the development of abrasive agents in personal care products, it is important to consider the composition of soaps and scrubs from the late 19th and early 20th centuries (Table 3). During this period, patenting new product formulations became increasingly common. Abrasive agents added to cosmetic soaps were often sourced from natural materials. These included china clay, bentonite [83], calcined diatomaceous earth [84], Fuller’s earth [85], tripoli [86], volcanic ash [87], feldspar [87], powdered pumice, bath bricks [88], amorphous silica [89], cornmeal [90], sawdust [91][92], ground wood [91], and cork [91]. By 1938, reviews on soap compositions, including on abrasive components, began to emerge [93], and in 1939, a comprehensive review of abrasives in soaps and scouring powders was published [94].

Table 3. Patents on new detergents, cosmetic soaps and toothpastes utilizing inorganic salts and organic natural products as abrasives/polishing agents.

Some drawbacks were noted regarding the use of certain abrasive materials in cosmetics, including challenges related to sourcing and shelf life, especially concerning microbial growth. Additionally, it was observed that some abrasives, particularly those found in toothpastes, could cause microinjuries to the skin, teeth, and mucous membranes [99]. In fact, F.E. Lauster in patent US3683065A [98] on liquid dentrifice clearly distinguishes between‚ abrasion/abrasive’ and “polishing agent”, which indicates that abrading was seen to have some connotation close to mechanically damaging tooth enamel. In the patent, dicalcium phosphate dihydrate (CaHPO₄·2H₂O) is seen as a possible polishing agent.

Table 4.Early patents which specify the development, formulation and production of plastic microspheres for cosmetic use.

Table 5. Patents on formulations of cosmetics, detergents and scouring liquids that contain solid polymeric microbeads/powder as abrasives/polishing agents and for coloration, spanning five and a half decades.

The introduction in the second half of the 20th century of synthetic polymer MBs as uniform and controllable exfoliants occurred against this backdrop (Tables 4-5). They were seen as mild abrasives and polishing agents with predictable textures, particle sizes, and exfoliation efficiency that came at a competitive cost. Early patents of synthetic MBs in personal care products began in the 1960s, with the first relevant patent in regard to plastic MBs granted in July 1965 [100], but they were not regularly included commercially until the 1990s, when they were considered a go-to source of innovation in personal care products. In 1972, MBs were patented for their current use in cosmetics as cleaning or exfoliating agents [111], and were only seen infrequently until the early 1990s [119], when cosmetic manufacturers started substituting synthetic polymeric beads for the most common inorganic peeling ingredients of the time, such as aluminum oxide [42], or other natural materials like millet or pumice peels [120]. MBs had become so common by the early 2000s that it was estimated that every household used at least one microbead scrub on a regular or weekly basis [54]. With the article by Zitko and Hanlin in 1991 [119], academia and the general public were made aware of the polluting potential of microplastics from rinse-off cosmetics. It was not until 2015, with the passage of the Microbead-Free Waters Act [45] by the U.S. Congress in 2015-2016, that a major country enacted binding legislation to restrict the use of plastic microbeads in rinse-off PCCPs. Consequently, the majority of plastic microbead use in rinse-off PCCPs occurred between approximately 1991 and the point at which meaningful legislation was introduced in a given region.

The first patents on the use of plastic microbeads/plastic microparticles in PCCPs, especially in body scrubs and other rinse-off cosmetics, made use of polyolefins as materials [100], specifically polythene and polypropylene. Examples of synthetic solid particles used in PCCP formulations include nylon, silicone resin, poly(meth)acrylate, polyethylene, polyester, polypropylene, polystyrene, polyurethane, polyamide, epoxy resin, urea resin, and acrylic powder (Table 6). Non-limiting examples of useful solid particles include Microease 110S, 114S, 116 (micronized synthetic wax), Micropoly 210, 250S (micronized polyethylene), Microslip (micronized polytetrafluoroethylene) and Microsilk (a combination of polyethylene and polytetrafluoroethylene), all of which are available from Micro Powder, Inc. Other examples include MP-2200, BPA-500 (polymethylmethacrylate), EA-209 (ethylene/acrylate copolymer), SP-501 (nylon-12) available from KOBO Products Inc., e.g., via Equistar, SP-10 (nylon-12), ES-830 (polymethylmethacrylate), BPD-800, BPD-500, BPA-500 (polyurethane) and CL2080 (polyethylene) particles, obtained from Quantum Chemical. Spherical polyethylene is also sold under the trade name Microthene, including MN701, MN710, MN-714, MN-722 and FN5100 (Table 7). Nylon particles are available from Elf Atochem under the trade name Orgasol. Advanced Polymer Systems (Advanced Examples include Microsponge and Polytrap acrylate copolymers available from Polymer Systems, and the Tospearl particle silicone resin sold by GE Silicones. Also useful is Ganzpearl GS-0605 cross-linked polystyrene (available from Pre- sperse).

A search in google patents® with the keywords‚ microthene’ and‚ cosmetics’ delivered 1262 results. Although the authors did not examine all 1,262 patents individually, a review of the first 100 results clearly showed that the vast majority (90%) referred to Microthene™ FN510-00 (Equistar), MicrotheneTM MN 727 or MicrotheneTM MN 710-20, all being polythene MBs. It should be noted, however, that in most patented formulations for personal care products (Table 6), a wide range of options is typically specified for the solid particles, encompassing natural, semi-synthetic, and fully synthetic materials. These include patents applied for in the first decade of the 21st century. Patents by Gonzalez et al. [121], Tanner and Manohar [122], and Osborne [123] illustrate this point. Even in the second decade of the 21st century polythene was included in some patents—these pertained to solid, leave-on cosmetics. It should also be noted that the above named commercially available plastic MBs/plastic microparticles are marketed for a whole range of purposes and have other uses such as binders in filters and battery materials or as carriers/matrices in fabrics or paper (Table 7).

Table 6. Patents on formulations of cosmetics, incl. toothpastes, with visible solid plastic microbeads and/or solid microbeads containing synthetic polymers as cleansing/polishing agents.

*HDI = Hexamethylene diisocyanate.

Table 7. Typical plastic microsphere products used in cosmetics over the years. There are many other uses for the products as in packaging, agriculture, healthcare, and industrial products. Typical examples are the use as binders in filters and battery materials or as carriers/matrices in fabrics or paper.

The first influential study to examine plastic microbeads in PCCPs, while also emphasizing their potential as environmental pollutants, originated in Canada, in which Zitko and Hanlon [119] analyzed two skin cleaners. One contained a small concentration of MPs of undefined composition, while the other had an appreciable concentration of polystyrene beads. New Zealand [119]. Both of the next studies originate from New Zealand, where Gregory [132] found MPs in 3 hand cleaners and in 3 facial scrubs and Fendall and Sewell [54] identified plastic microbeads in four PCCPs (Table 8). In 2015, Chang published a study examining nine branded PCCPs that were selected from a larger pool based on the presence of polyethylene listed in their ingredient list [60][133]. In the same year, Napper et al. [25] published their results on six PCCPs sourced in Plymouth, UK, which were again selected as they had listed PE as an ingredient. In 2017, Cheung and Fok [134] looked at 9 popular PCCPs used in Hong Kong SAR and found that all 9 possessed PE/LDPE MBs. Two other studies on the presence of plastic MBs in PCCPs were published in 2017, one from China [135] and the other from Slovenia [136]. In 2018, Praveena et al. [137] studied 5 facial scrubs and 5 tooth paste products commercially available in Malaysia. Here, all facial scrubs contained either PE or PP microbeads, while the microbeads of only one toothpaste brand were made of PE.

The Microbeads free water act of 2015 instituted a sales ban in USA of plastic MB containing rinse-off PCCPs from January 2018 onwards, and this would be expected to have had a substantial impact on the production and distribution of U.S.-manufactured products, including their export to global markets, which also includes at the time existing stocks, as well as on the formulation and distribution of international products beyond the United States. Two notable studies published in 2019 merit attention, as this year represents a transitional period in the regulation of microplastic-containing microbeads, while acknowledging that the findings reported in 2019 are based on research conducted in preceding years. Godoy et al. [138] published an extensive investigation of PCCPs acquired in Granada, Spain, encompassing over 1500 products, including 68 scrubs. Although PE microbeads were present in 42.6% of the scrub products, their overall occurrence across all products analyzed was relatively low, at 1.82%. Ustabasi and Baysal [139] studied the compositions of 20 toothpastes bought in Istanbul, Turkey, where 20% of the samples were found to contain PE MPS at concentrations between 0.4 and 1 w%.

In the years after, numerous studies investigating the presence of plastic microbeads in PCCPs have been conducted across different regions and time periods. This temporal and geographic variation is important to consider, as regulatory frameworks governing the use of plastic microbeads in rinse-off cosmetics have differed between regions and over time, and continue to do so today, as outlined below. Indeed, presently some countries have implemented outright bans on rinse-off cosmetic products containing plastic microbeads, resulting in the removal of such products from the market and the imposition of fines on non-compliant companies. In other regions, stringent restrictions on microplastic-containing cosmetics are imminent, and only a limited number of rinse-off PCCPs containing microplastics remain available; however, enforcement mechanisms, such as active market surveillance, are often lacking. Finally, there are countries where no specific legislation addressing microplastic-containing rinse-off PCCPs exists, or where proposed regulations have not yet been enacted. In many instances, these measures are introduced not as stand-alone regulations but as part of broader initiatives aimed at reducing or banning single-use plastics more generally. Implementation is frequently delayed, sometimes for several years. These latter jurisdictions are often of particular interest when assessing the range of PCCPs available on the market. Accordingly, during our investigation of microbead-containing rinse-off cosmetics and toothpastes in the United Arab Emirates between 2018 and 2022—a period in which the UAE did not yet have comprehensive legislation addressing single-use plastics—it was noteworthy that the availability of products containing plastic MBs declined over time [140][141]. Nearly all rinse-off products manufactured in the UAE were free of plastic MBs and instead contained natural exfoliating materials, such as ground walnut shells. Products that continued to contain plastic MBs were, interestingly, imported by companies based in East Asia, Europe, or the United States. With respect to toothpastes, no products containing plastic MBs were identified in UAE supermarkets [142]. This includes products directly imported from Syria. The authors also obtained products through online retail platforms. Here, interestingly only toothpastes that predated the implementation date of the US Microbeads free water act of 2015 were found to have plastic MBs.

A number of recent studies from South Asia, particularly from India, Pakistan, and Sri Lanka, indicate that a substantial proportion of PCCPs still contain plastic microbeads. Thus, Gamage and Mahagamage [143] analyzed 15 personal care products available in Sri Lanka, including face washes, facial scrubs, baby creams, shaving creams, and skin creams, and identified microplastics in only six brands. The detected particles were predominantly white and consisted mainly of low-density polyethylene and ethylene–propylene copolymers, with particle sizes ranging from 238.55 ± 50.74 to 450.69 ± 174.9 µm. For identification, the study used the dying of the particles with Nile red and FT-IR spectroscopy. In Punjab, Pakistan, Hussain et al. [144] have studied 103 body scrubs and face washes from different markets in Jhang, Multan, and Bahawalpur and found that 47 (45.6%) products incorporated plastic microbeads, including 44 (42.7%) products that exhibited polythene microbeads. A smaller number of rinse-off cosmetics was scrutinized by Bhasvar and Gore [145] where three out of the analyzed six PCCPs contained polyethylene (PE) beads. Madhumitha et al. [146] found MPs in all the ten tooth pastes investigated, which were acquired in Tamil Nadu markets.

Further studies come from East and South East Asia. In 2021, Bashir et al. [147] looked at 144 PCCPs that were bought in Macao, China. Of the 68 facial cosmetic products analyzed, 44 (64.7%) contained microplastics in their formulations; specifically, polyethylene was detected in 43 products, polyethylene terephthalate in three products, and nylon in one product. Among the 31 body cosmetic products examined, 9 (29.0%) contained polyethylene microplastics. In addition, all 45 of the remaining cosmetic products analyzed contained microplastics, including 24 with polyethylene (PE), 3 with polyethylene terephthalate (PET), 12 with polymethyl methacrylate (PMMA), and 14 with nylon. The three top-sale products containing microplastics were found to have particles of the size range of 11 to 968 μm. The MP concentrations were 7,674, - 18,216 P/g product with a weight percentage of 1.8 - 5.2%. In Selangor, Malaysia, Suardy et al. [148] found that all of the 6 investigated products contained MPs, 4 of them PE and 2 polystyrene (PS). Dung et al. [149] reported on the composition of 9 PCCPs from Ho Chi Minh City, finding MBs in all of them. In regard to the composition of the MBs, Dung et al. rely mostly on the ingredients lists. Only 2 of the 9 products contain PE MBs.

In the time period 2020-2023, three important studies originated from Eastern Europe. In Romania, Banica et al. [150] found MPs in all 5 PCCPs analyzed, which included body sprays and shower gels. In a 2020 publication, Piotrowska et al. [151] reported that, among 130 randomly selected scrub-type cosmetic products from 74 different manufacturers, 58 products (44.6%) contained natural abrasives, while 50 products (38.5%) contained polyethylene microparticles. Twenty-two cosmetics (19.9%) included both polyethylene and abrasives of natural origin. Three year later, in 2023, Guzik et al. [152] published that she and her team had isolated MPs from 13 of 50 randomly selected rinse-off products. Here, however, PE was not present in any of the products; instead, the formulations contained acrylate/C10-C30 alkyl acrylate crosspolymers, polystyrene-acrylate copolymers, and polylactic acid [152].

Two further, recent investigations come from Iran and Russia. Nasrabadi et al. [153] found that all the 6 PCCPs they chose from markets in Iran carried microplastics, mostly PE. 4 of 8 PCCPs from Russian markets as analyzed by Zorin et al. [154] carried MPs.

In all, it must be realized that many of the early investigations of PCCPs specifically looked at cosmetics with MPs to measure their concentrations, compositions and sizes [54][60][119][132][133]. Only a limited number of published academic studies [135][138][140]-[143][147][151][152] have examined a sufficiently large sample of cosmetic products to provide a robust assessment of microplastic prevalence in the marketplace. Nevertheless, the available studies suggest that within the European community [136][151], the number of PCCPs with intentionally added microplastics has declined markedly. Similar reductions have also been observed in certain regions, such as parts of the Middle East, where the prevalence of microplastic-containing PCCPs has decreased significantly [140]-[142], although no specific legal restrictions are in place, yet. Data from South Asia suggests that MP containing PCCPs are still on the market [142][143][145][146]. Recent academic studies on the prevalence of MPs in PCCPs from North America, the European community and Japan are scarce.

Table 8. Published studies of MP content in PCCPs in different countries.

Several research projects incorporated questionnaires on the preferences of consumers and their usage patterns of PCCPs [60][133][140][141], enabling estimates of the release of plastic microbeads from these products into wastewater systems and, subsequently, their discharge into aquatic environments via wastewater treatment plant effluents. Thus, Chang surveyed 175 residents of a UC Berkeley student residential hall using an online questionnaire and estimated that approximately 5 kg of microplastic beads per year entered the wastewater stream from this group alone [60]. In 2011, Gouin et al. [155] estimated that per capita consumption of microplastics from personal care products in the United States, based on the use of polyethylene microbeads, was approximately 2.4 mg per person per day. This corresponded at the time to an estimated annual release of about 263 tonnes of polyethylene microplastics by the U.S. population. In the years 2014-2017, position papers were published by governmental institutions from Sweden [156], Norway [157], Denmark [158] and Germany [159], which approximated the release of plastic MBs due to dispersal of PCCPs into the environment (Table 9). Approximations ranged from 9 - 29 tons/year for Denmark [158] to 500 tons/year for Germany [159]. Approximations also exist for China [160][161], the UK [25][161], New Zealand [132] and USA [161], among others.

Table 9. Estimation of the release of plastic microparticles in form of tire wear and synthetic fibers, from personal care products and due to spillage of virgin plastic pellets in different countries.

In the early 1970s, small polystyrene spherules, generally < 2.00 mm in diameter, were found to be widespread in coastal and surface waters of the north-western Atlantic Ocean [162][163]. They were thought to derive mostly from spillage of virgin beads [164]. Then, there were larger, up to 5 mm or more in diameter, polyethylene and polypropylene granules. With the publications of Zitko and Hanlon [119] and Gregory [132], the public eye turned to PCCPs as one of the culprits for the PE and PP microsphere contamination of the marine environment. While nowadays the sources of MPs in the oceans are seen to be manifold, the quantity of plastic NPs alone across the Northern Atlantic may have increased to 27 million tonnes [165]. Already, in the early 1970s, it was noted that the microspheres would most likely be ingested by many seabird and fish species, and that there would be the possibility of an intestinal blockage in these organisms [132]. The detrimental effects of MP ingestion [36] by fishes has been studied extensively [166]. Overall, the results indicate that MPs exposure significantly inhibits fish growth [167], survival, and reproductive ability, and increases oxidative damage. In addition, to the adverse effects of MPs on fishes, many of them of great commercial value, it was seen that MPs could also be transferred to humans via the ingestion of seafood [37][38]. Equally of concern was seen the direct human exposure to MPs through skin contact, eye contact and through ingestion of MP laden toothpastes.

Reviews have appeared on potential health impacts of microplastics in general and of microplastics from cosmetics [68][69]. It is important to distinguish between the direct effects of microplastics resulting from dermal exposure and the potential health impacts associated with their release into the environment, which may lead to human ingestion [168]. This distinction is further complicated by the ability of microplastics to adsorb and transport harmful chemical or biological substances [169]. Human ingestion is also a relevant consideration in the case of microplastic-containing toothpastes [44]. In the following, only the effects of dermal exposure to microplastics are addressed.

Dermal exposure to MPs is generally regarded as a less significant pathway of entry of MPs into the human body. Skin permeability is influenced by several factors. Particle size is particularly important: nanoplastics are more likely to penetrate the skin, whereas larger particles may enter via hair follicles, sweat glands, or through abrasions in the skin [170][171]. It should be noted that the majority of plastic particulate matter found in cosmetic formulations is typically in the microplastic (MP) size range rather than the nanoparticle (NP) range, so that the risk of direct dermal penetration is very small.

Nevertheless, in vitro studies using primary skin cells have shown that nano-sized plastics can penetrate and accumulate within skin tissues, with particles up to 6 µm being taken up by keratinocytes [172]. Further research indicates that nanoplastics smaller than 200 nm can migrate through skin furrows, lipid pathways, and hair follicles, reaching the viable epidermis and, in some cases, being internalized by skin cells [173]. MPs that have penetrated the skin can potentially interact with cells and structural biomolecules.

Upon contact with the skin, these particles can elicit immune responses through the recognition of pathogen-associated and damage-associated molecular patterns by receptors expressed on keratinocytes, Langerhans cells, dendritic cells, melanocytes, macrophages, and T cells [174]. Activation of these signaling pathways leads to the release of antimicrobial peptides and pro-inflammatory cytokines—including interleucins IL-1, IL-6, IL-10, IL-17, IL-18, and IL-22, and tumor necrosis factor (TNF)—which disrupt skin homeostasis, promote the recruitment of additional immune cells, and compromise the structural integrity of the epidermis [175][176]. Specifically, it has been shown in an internalization experiment of PE MPs (8 μm, 1000 ng/L) in gill skin cells that PE MPs activate the NF-κB signaling pathway which centrally mediates inflammation and immune regulation and leads to an increased expression of pro-inflammatory cytokines, including TNF-α, interferon-γ (IFN-γ), IL-2, IL-6, IL-8, and IL-1β and a concurrent suppression of anti-inflammatory cytokines such as IL-4 and IL-10 [177]. Furthermore, emerging evidence indicates that microplastics can enter cells, disrupt essential biological functions, and promote the formation of a carcinogenic microenvironment [178][179]. These particles may contribute to carcinogenesis through multiple mechanisms, including the induction of DNA damage, oxidative stress, inflammatory responses, and disruption of cellular signaling pathways. In addition, microplastics may promote tumorigenesis through mechanisms such as endocrine disruption and genetic as well as epigenetic alterations, including changes in DNA methylation [180], histone modifications, and microRNA dysregulation [69].

According to Dauvergne [181], the Beat the Microbead campaign (www.beatthemicrobead.org) published that as of February 2018, nearly 450 brands across 119 companies had pledged to eliminate microbeads from their rinse-off products, which is also the number in January 2026. This promise was adopted by some of the biggest brands in the world such as L’Oréal, Colgate-Palmolive, Beiersdorf, Procter & Gamble, and Johnson & Johnson.

Table 10.Regulations of different countries or regions in respect to single use plastic in rinse off cosmetics.

* As an EC member state, the country follows the Commission Regulation (EU) 2023/2055.

As early as in 2014, the Netherlands, Austria, Belgium and Sweden issued a joint call to ban the use of microplastics in cosmetics to protect marine life. At the same time, the Dutch government implemented a voluntary industry agreement with cosmetic manufacturers and retailers. for the phase-out of microbeads in rinse-off products sold in the Netherlands. It was highly successful—by 2016, over 90% of such products were microbead-free. Also, in 2014, Illinois became the first jurisdiction in the world to ban products from containing microbeads. This set a precedence for eight other US states [Colorado, Wisconsin, Indiana, Maine, Maryland, New Jersey, Connecticut and California] and the American federal government to enact similar laws. The state of California became the first jurisdiction in the world to ban the use of all microbeads, including biodegradable microbeads. In 2015, the province of Ontario formulated Bill 75, Microbead Elimination and Monitoring Act, 2015 [202], which would prohibit the manufacture of microbeads and the addition of microbeads to cosmetics, soaps or similar products. In addition, the bill would require the province to conduct water sampling for microbeads in the Great Lakes. Canada as a whole followed suit in 2018, imposing a ban on MP containing toiletries. As in many other countries and regions, the ban was preceded by a comprehensive introduction to the planned regulation and consultation documentation with a 75-day public comment period [203], including a document on the status of scientific knowledge in respect to the interaction of plastic microbeads and the environment [204]. EC-restrictions in regard to microplastics are currently governed by Commission Regulation (EU) 2023/2055 [200] and amends Annex XVII to Regulation (EC) No 1907/2006 of the European Parliament and of the Council concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). In South Korea, microplastics used as raw materials in cosmetics such as bathing and cleaning products were forbidden according to the “Regulations on Safety Standards for Cosmetics” as of July 2017 [205][206]. According to Lee and Kim [205], cosmetic products manufactured prior to this regulation continued to be sold for some time, at least in 2018. Therefore, it was seen that despite the prohibition, microplastics continued to discharge into sewage treatment facilities (STFs) from personal care products. In June 2023, South Korea proposed the Special Act on Microplastic Reduce and Control, which aims to comprehensively manage microplastic usage and emissions, which prohibits the manufacture and import of products containing microplastics above safety thresholds. Meanwhile, Australia - Australia has implemented a voluntary industry phase-out but not a ban of plastic microbeads in rinse-off cosmetics and personal care products since 2018. This includes products like exfoliants, cleansers, and toothpaste [207]. Table 10 shows a list of regulations forwarded by different governments.

Many government bans limit themselves to rinse-off cosmetics, but do not touch microplastics when they are liquid polymers and powdered plastics used in makeup foundations, sunscreens, hair gel, and eye drops [208]. Also, most of the research on plastic particle content in cosmetics has focused on rinse-off products (Table 8), including toothpastes [138][142]. It is here that Kukkola et al. [209] have warned that MP containing leave-on products are widely understudied, that a uniform methodology of MP identification from leave-on products is, for the most part lacking and that regulations and monitoring of these products are largely missing. The first explicit inclusion of leave-on PCCPs in microplastic-related guidelines occurred in the Nordic Swan ecolabel criteria [210], established in 2010. The Nordic Swan is a voluntary ecolabel awarded to products and services that meet high environmental standards across their life cycle, with the objective of promoting sustainable development and environmentally conscious consumer choices. This initiative was followed by the introduction of similar provisions in the EU Ecolabel in 2021 (EU 2021/1870) [211]. The incorporation of microplastics in leave-on PCCPs within ecolabel schemes reflects a growing awareness of their presence in such products and their potential environmental impacts. This progression culminated in the first binding legal framework addressing microplastics in leave-on PCCPs, introduced through the September 2023 amendment to the REACH Regulation (EC No 1907/2006) [212]. This amendment added synthetic polymer microparticles to the REACH Restrictions List (Annex XVII), thereby prohibiting the intentional addition of microplastics to products placed on the EU market. The amendment states a transitional period of 12 years for the ban on placing on the market of MP containing leave-on products. This affects especially make-up, lip and nail products.

Overall, legislation addressing plastic microparticles in PCCPs, including rinse-off cosmetics, remains highly heterogeneous. This variability is particularly evident in the implementation and enforcement of existing regulations. International trade between regions with established bans on microplastics and those without such restrictions further complicates regulatory effectiveness. This challenge is illustrated by the study of Not et al. [213], which examined products purchased in regions where bans had already been implemented (e.g., Canada and the UK), where bans had been announced but not yet enforced (e.g., Italy), and where no restrictions had been introduced (e.g., Hong Kong SAR and Japan). Notably, PE MPs were detected in products obtained from all three regions.

The state of New South Wales, Australia, was one of the first jurisdictions to penalize wholesalers, manufacturers and distributors, when issuing non-compliance notices to six businesses in regard nine different MP carrying cosmetics on the shelves. Failing to comply with a Compliance Notice carries a maximum penalty of up to A$550,000, plus A$55,000 for each additional day the offence continues [214].

Development of cosmetic formulations has always been ambident, one route utilizing synthetic polymers, the other making do without for many of the needed components. This includes the time period between the early 1990s and the 2010s. It must be noted that microcrystalline wax appearing on the EU Cosmetics Ingredient Database (CosIng) under the INCI name Microcrystalline Wax/Cera Microcristallina is still commonly used as a binding, viscosity-controlling, and emollient ingredient in creams, lipsticks, balms, and other cosmetics as there is no general ban on its use in cosmetics under Regulation (EC) No. 1223/2009. Its use in cosmetics is also allowed in USA. As the wax derives itself from petroleum refining, being composed mainly of branched and cyclic saturated hydrocarbons, albeit of smaller molecular mass than PE and of lower melting point (60 - 90˚C vs. 100 - 110˚C for PE), regulatory bodies generally require that cosmetic-grade microcrystalline wax is highly refined to reduce impurities such as polycyclic aromatic hydrocarbons (PAHs).

A look into Table 11 shows typical patent applications utilizing microbeads based on inorganic material and polysaccharide material both as cleansing particles and as rheological modifiers. These efforts continue in the 2020s (Table 12). Polysaccharides used include cellulose, starch, alginate, chitosan, pectin, agar, xanthan gum, guar gum, and hyaluronic acid. Many of these materials are also utilized in microparticulate or powdered forms, owing to their film-forming and emulsifying capabilities, as well as their capacity to modify formulation rheology [215]. In addition, several polysaccharides exhibit beneficial functional properties, such as antimicrobial activity (chitosan; [216]), antistatic effects (cellulose; [217]), moisturizing capacity (chitosan; [216]), and skin-protective effects (hyaluronic acid; [218]). Some of the polysaccharides used are synthetically modified such as carboxymethylcellulose (CMC), which can be prepared as its sodium salt via the etherification of cellulose with sodium monochloroacetate in an alkaline solution (NaOH). CMC is a versatile ingredient in both cleansing agents and cosmetics. It serves as a thickening agent, stabilizer, emulsifier, and film-forming agent. CMC microbeads are used improve the texture and feel of cosmetic formulations.

As an example of the production of environmentally benign alginate microbeads to be used as scrubbing additives, Ca-alginate MBs of 540 to 1120 μm size were fabricated by electrospraying an aqueous alginate solution into distilled water containing calcium ions [219]. Ca- and Ba-alginate microspheres as delivery systems for active ingredients in cosmetics were investigated in the presence/absence of surfactant in oil-in-water (o/w) emulsions [220]. Kozlowski et al. [221] developed spherical microparticles made of sodium alginate and a mixture of sodium alginate and starch using encapsulator BÜCHI B-395.

Chitosan’s capacity to interact electrostatically with negatively charged substrates, such as skin or damaged hair, leading to the formation of polymeric films that enhance conditioning and moisturization, makes it an excellent candidate for skin and hair care formulations [222]. Chitosan microbeads have also been proposed for use as drug delivery system [223]. Ju et al. [224] prepared microbeads from chitosan via an inverse emulsion system using sorbitan monooleate (Span® 80) as a non-ionic surfactant. Thereafter, the amino functions on the surface of the prepared microbeads were acetylated with acetic acid anhydride. These so-called cito-beads with a narrow size distribution of 280 μm possessed a better skin-cleansing efficiency than commercially available plastic MBs.

Table 11.Patents in regard to the development and manufacture of microbeads/microparticles with useful applications in cosmetics that do not contain plastic materials.

Table 12. Recent patents showing the breadth of the use of naturally sourced material, including oligosaccharide, in cosmetics as thickeners, stabilizers, anti-aging/anti-wrinkling agents and as part of UV filters.

O’Brien et al. [236] developed spherical cellulose microbeads using a scalable membrane emulsification phase inversion process as an environmentally friendly alternative to plastic microbeads. Patents have forwarded the use of commercially available cellulose granules (such as KC Flock W-400TM or W-100TM, manufactured by Nippon Paper Ind.) as abrasive agents in cleansing products [228][237][238]. More recently, bacterial cellulose (BC) has gained attention in this field due to its high purity, porosity, and tensile strength. BC has the same chemical composition as plant-derived cellulose, differing only in molecular weight [239]. This polymer has been explored for use in cosmetic applications, including personal care formulations, and facial scrubs [240].

Thus far and in general, compared with synthetic polymer beads, natural alternatives used in cosmetics often provide milder and less uniform abrasiveness due to their irregular shape and variable hardness, which can reduce exfoliation consistency. However, these natural materials are frequently perceived as offering a more pleasant, skin-friendly sensory feel, albeit with greater batch-to-batch variability than synthetic beads. The inclusion of newly developed microbeads/microparticles in cosmetic products will depend on the ease of sourcing and on cost. Further development of regulatory frameworks will shape the future evolution of cosmetic ingredients and remains essential for ensuring consumer health and safety.