What are acrylates and why are they used in cosmetic and personal care products?

Acrylates are a family of cosmetic ingredients synthesized into a variety of different types of polymers/copolymers (linear chains), and crosspolymers (chains tied together by a crosslinker). The ingredients subject to Credo’s prohibition are the acrylate monomers (i.e., ethyl acrylate, ethyl methacrylate, butyl methacrylate, methyl methacrylate, hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, trimethylolpropane trimethacrylate). The main function of the monomers, beyond being feedstock for the polymers, is in artificial nail products: gel nail polishes and liquid-and-powder nail systems. In these uses, the monomers are applied in uncured form and must be finished, or ‘cured,’ by radical polymerization: UV or LED light in gel systems, and a chemical initiator in liquid-and-powder systems. This process is what creates the hard and long-lasting finish.

What does science say?

Acrylate monomers are known skin sensitizers (1). Methyl methacrylate was the subject of an FDA evaluation in the 1970s after receiving complaints associated with artificial nails containing methyl methacrylate including fingernail damage and deformity, and contact dermatitis (2). Several of the other acrylate monomers have been reviewed by a U.S. expert panel of scientists, the Cosmetic Ingredient Review panel, which concluded they are safe in nail enhancement products only when skin contact is avoided (3,4).

Why does Credo restrict acrylates?

Given the known sensitization potential of these compounds, Credo restricts them in products. Even if contact with skin is avoided and application is only to the nail plate, unintentional skin exposures may occur. In addition, manicurists, who may apply the products multiple times a day can experience an increased probability of sensitization from unintentional exposures (5).

Credo's approach

Credo's ingredient restrictions are informed by the Credo Methodology™.

What is Aluminum Powder and why is it used in cosmetic and personal care products?

Aluminum Powder (also known as CI 77000) is elemental aluminum in a fine powder form. In cosmetics, aluminum powder is used as a metallic pigment to add a silver/grey lustre. It is not an active ingredient and it is not the aluminium found in antiperspirants, which is a different class of compounds (aluminum salts).

What does science say?

In 1977 the U.S. FDA approved CI 77000 as a colorant, with the approval requiring purity specifications along with prescribed conditions of use (1,2). Specifically, CI 77000 is approved for use in externally applied cosmetics, including products for the eye area but not lip products, subject to purity specifications. This approval was not published along with any public safety assessment and aluminum powder (CI 77000) has never been individually assessed by the US Cosmetic Ingredient Review Expert Panel.

The EU's Scientific Committee on Consumer Safety has published a series of five documents on aluminium in cosmetics between 2014 and 2024 (3–7), but these assess aluminium-containing ingredients as a class, on an elemental aluminium basis; i.e., it is not specific to aluminium powder but describe aluminium generally. In 2014 SCCS noted that aluminium is a "known systemic toxicant at high doses", meaning at high enough doses there can be adverse effects on the body. This conclusion was grounded in historical toxicology studies^a with ingested aluminium. However, SCCS was not able to conclude at that time if exposure to aluminium from cosmetics actually posed a human health risk because there was no available data on how much aluminium passes through skin and if this amount was greater than or less than the amount known to cause toxicity (3).

In 2020 data became available that demonstrated a minimal amount of aluminium can get through the skin, approximately just 0.0005% of the applied amount of aluminum can enter the body (4). On that basis, the SCCS concluded that aluminium-containing ingredients are safe when used at or below maximum levels SCCS specified for given product categories (7).

SCCS also noted that diet is a major source of aluminium exposure, contributing on a similar order of magnitude to cosmetics under its conservative estimates, and that when cosmetic, dietary and pharmaceutical sources are combined, the most highly exposed consumers may exceed established safe intake limits (6,7). Neither SCCS nor CIR have evaluated inhalation exposure to aluminium powder from loose powder formulations; the assessments above address dermal and oral route.

Why does Credo prohibit Aluminium Powder?

Based on a review of the available data Credo has opted to take the precautionary approach and prohibit aluminium powder from any products sold by Credo to minimize the potential for any adverse human health affects. These ingredients also reach people through sources beyond cosmetics and each of those uses is reviewed for safety on its own rather than added together. Where credible evidence points to the potential for long-term health concerns (even amid uncertainty) and viable alternatives exist, Credo applies a precautionary approach rather than waiting for the science to settle.

Credo's approach

Credo's ingredient restrictions are informed by the Credo Methodology™.

What are animal-derived ingredients and why are they used in cosmetic and personal care products?

Animal-derived ingredients are ingredients obtained from animals or animal byproducts. They are used in cosmetics for a variety of purposes, including moisturizing, conditioning, emulsifying, and improving product texture. Many of these functions can also be achieved using plant-derived, mineral-derived, fermentation-derived, or synthetic alternatives.

What does science say?

Animal-derived ingredients are not inherently safer or less safe than ingredients from other sources. Their safety depends on the specific ingredient, how it is manufactured, and how it is used in a formulation. In many cases, the same ingredient can be sourced from animals, plants, or synthetic processes while providing the same function and performance.

Why does Credo restrict animal-derived ingredients?

Credo's restrictions are based primarily on ingredient sourcing (i.e., the use of animals); not on any human health concern. When a comparable non-animal alternative is available, Credo requires ingredients to be sourced from plants, minerals, fermentation, or synthetic processes instead.

Recognizing that suitable alternatives are not yet available for every application, Credo permits a very limited number of animal-derived ingredients. These are: beeswax^a, lanolin, keratin, shellac, cholesterol, lactose, and carmine. Brands are encouraged to obtain assurances that these ingredients are sourced with consideration for animal welfare.

Animal-derived ingredients vs. animal testing

Animal-derived ingredients and animal testing are separate issues. An ingredient may be animal-derived without the finished product or its ingredients being tested on animals.

Credo does not permit any products that are tested on animals.

Credo's approach

Credo's goal is to encourage thoughtful ingredient sourcing. Rather than prohibit every animal-derived ingredient outright, our standard prioritizes non-animal alternatives where they offer comparable performance, while recognizing that certain applications may still require animal-derived materials and we aim to support functional alternatives to these as much as feasibility possible. Note, Credo’s online product listings will show a “vegan” label if you’re looking to ensure a product doesn’t use any animal derived ingredients.

What are butylated ingredients and why are they used in cosmetic and personal care products?

Butylated ingredients are a class of ingredients that have been chemically modified to improve their stability or performance. In cosmetics, some butylated ingredients are used as antioxidants to help prevent oils and other ingredients from breaking down over time, while others help stabilize formulations or improve product performance (1). Common examples include butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).

What does science say?

In the US, the Cosmetic Ingredient Review (CIR) Expert Panel has reviewed both BHA and BHT repeatedly since the 1980s and concluded that both are safe in cosmetics as currently used. CIR doesn’t set a maximum limit, it reviews the concentrations industry reports using, most recently up to 0.5% for BHT and 0.15% for BHA (2,3). In the EU, BHT has been restricted in law since 2023 to 0.001% in mouthwash, 0.1% in toothpaste and 0.8% in other products (4). These restrictions are concentrations at which adverse liver and reproductive and developmental effects are not anticipated to occur.

BHA has never been regulated in the EU. In March 2026 the Scientific Committee on Consumer Safety (SCCS) recommended limiting the amount allowed in cosmetics to 0.07%. Below this proposed maximum concentration adverse liver effects are not anticipated to occur. Notably oral care and products that could be inhaled, such as sprays and loose powders, were not included in this evaluation (1). BHA is also classified as “possibly carcinogenic to humans” (Group 2B) by the International Agency for Research on Cancer and as “reasonably anticipated to be a human carcinogen” by the US National Toxicology Program (5,6). These are hazard classifications: they ask whether a substance could cause harm under some conditions, rather than whether it does at the amounts people are actually exposed to. These classifications are primarily based on a type of tumor observed in rodents fed high doses of BHA over long periods^a which have been deemed of minimal relevance to humans (7,8), though this conclusion has not been withdrawn by either agency. Reviewing the same evidence, both the SCCS and the CIR Expert Panel concluded that carcinogenicity is not a concern at the concentrations used in cosmetics (1,3).

Whether these ingredients affect hormones is a question that remains open. For BHT, the SCCS found that neither computational modeling nor cell studies indicated endocrine-disrupting properties (9). However, there is evidence at high enough exposure it can cause adverse reproductive and development effects (9). For BHA, cell studies have shown estrogen-like and anti-androgen-like activity, but the available animal studies on hormonal effects were judged methodologically weak. The CIR Expert Panel similarly noted that effects appeared mainly in cell systems and at concentrations far above anything reached through cosmetic use (1,3). Independent researchers have also explored this question, landing on both sides of the debate (10–13).

Why does Credo prohibit butylated ingredients?

Because some butylated ingredients have shown endocrine activity in laboratory studies, along with adverse reproductive and liver effects, and because scientific questions about this class remain open, we choose to prohibit butylated ingredients in products sold at Credo. This is done out of precaution and in line with customer preference. These ingredients also reach people through sources beyond cosmetics, including food and food packaging, and each of those uses is reviewed on its own rather than added together. Scientific and regulatory bodies have reached differing conclusions about the concentrations and product types for which these ingredients are appropriate. Where credible evidence points to the potential for long-term health concerns (even amid uncertainty) and viable alternatives exist, Credo applies a precautionary approach rather than waiting for the science to settle.

Credo's approach

Product stability is essential to both product safety and performance. Credo encourages brands to formulate with antioxidant and stabilization systems that maintain product quality while avoiding butylated ingredients.

What is Carbon Black and why is it used in cosmetic and personal care products?

Carbon black is a fine black powder made almost entirely of elemental carbon. It is produced industrially by burning heavy petroleum oils or gas with a limited supply of air (1,2). Most carbon black made worldwide goes into rubber, mainly tires, with smaller amounts used as a pigment in inks, paints, coatings and plastics (1). In cosmetics it is used as a black colorant in eye makeup such as mascara, eyeliner, brow products and eye shadow. It may also be used in lipstick, blush, foundation and nail polish (2). On a label it appears as CI 77266 in the EU, or CI 77266 (nano) where the nano form is used, and as Black 2 or D&C Black No. 2 in the United States (3–5).

What does science say?

The concerns around carbon black are mainly related to potential inhalation exposure and environmental sustainability. Specifically, the International Agency for Research on Cancer (IARC) classifies carbon black as possibly carcinogenic to humans (Group 2B) (1). This classification is based on studies in animals that were exposed to carbon black dust via inhalation^a. Similar increases in cancer were not observed in studies of people exposed occupationally (1). California lists airborne, unbound particles of carbon black of respirable size as a carcinogen under Proposition 65, on the basis of the IARC classification (6). (Note: These are hazard classifications. They ask whether a substance could cause harm under some conditions, rather than whether it does cause harm at the amounts people are actually exposed to.) Both IARC and California note that exposure to carbon black does not occur when it remains bound within a product such as rubber, ink or paint (1,6).

Cosmetic regulators in the United States and the EU have both assessed carbon black as a colorant and permit its use. The US Food and Drug Administration (FDA) concluded in 2004 that there is a reasonable certainty of no harm from its use in eye makeup, lipstick, blush, foundation and nail polish (2). The FDA’s main concern was trace amounts of polycyclic aromatic hydrocarbons (PAHs), some of which are carcinogenic, that may be present in some carbon black particles. FDA sets strict purity limits and requires every batch sold for cosmetics to be certified before use (2,3). In the EU, the Scientific Committee on Consumer Safety (SCCS) concluded in 2015 that the nano form of carbon black, at up to 10% in a product, does not pose a risk when applied to healthy, intact skin, because very little, if any, passes through the skin (5). The SCCS was explicit in that this opinion did not apply to products that could be inhaled (5). Based on the current evidence, carbon black used as permitted in cosmetics is not expected to pose a cancer risk to consumers (2,5).

An additional consideration is that carbon black is made by burning heavy petroleum oils or natural gas, and the US specification for cosmetic carbon black requires this petroleum-based process (3). The process is carbon-intensive and has been a source of local air pollution around manufacturing plants (7,8). The International Carbon Black Association, the industry’s trade group, reported in 2025 that producing one ton of carbon black generates an average of 3.91 tons of carbon dioxide-equivalent emissions, with the feedstock and the manufacturing process accounting for most of that total (8). Cosmetics is only a small portion of the total usage of carbon black manufacturing.

Why does Credo prohibit carbon black?

Credo takes a precautionary approach: when credible evidence points to potential long-term health concerns and viable alternatives exist, we act rather than wait for the science to settle. Carbon black has shown potential carcinogenicity in laboratory studies, though the extrapolation of this data to humans has not been observed. In addition, petroleum is not a sustainable feedstock. Credo encourages brands to use natural, naturally-derived, or synthetic ingredients that are not of petroleum feedstocks whenever possible. In the instance of carbon black, alternatives are available. Based on this combined evidence base, Credo prohibits the use of carbon black in Credo-backed products.

Credo’s approach

Credo’s ingredient restrictions are informed by the Credo Methodology™.

What is Coal Tar and why is it used in cosmetic and personal care products?

Coal tar is a by-product of coal distillation (1). From a personal care perspective, it has been used in over-the-counter medicated shampoos and topical products as an anti-dandruff, anti-inflammatory, and anti-seborrheic agent (2,3). Coal tar is not a single chemical: it is a complex mixture of hundreds of compounds, including a family called polycyclic aromatic hydrocarbons, and its make-up shifts with the type of coal used and the temperature in which it was processed (1).

Credo’s coal tar category also covers several coal-derived fractions separated out of coal tar during processing, listed as naphtha, high solvent naphtha and naphtha distillate, together with the general term “tar.”

What does science say?

The FDA permits coal tar as an active drug ingredient at 0.5 to 5 percent for the control of dandruff, seborrheic dermatitis and psoriasis (2,3). Products containing it must carry warnings that skin may be more prone to sunburn for up to 24 hours after application, and that it should not be used for prolonged periods without consulting a doctor; leave-on forms must also warn against use in or around the genital area or groin (2,3). In the United States, coal tar is not restricted in cosmetics. However, it is also not reported to be used in them (4). The Cosmetic Ingredient Review (CIR) panel, an independent expert panel in the US, assessed coal tar as a cosmetic ingredient in 2008 and found the available data insufficient to determine safety. CIR deferred the anti-dandruff use to the FDA (3).

The International Agency for Research on Cancer classifies coal-tar distillation as carcinogenic to humans, its highest category (5). The US National Toxicology Program lists coal tars and coal-tar pitches as known to be human carcinogens, a listing first made in 1980 (1). The studies reviewed to reach this conclusion involved patent-fuel workers, pitch loaders and tar distillers, who showed excess skin cancer, including scrotal cancer, along with cancers of the lung, bladder and kidney (2). (Note: These are hazard classifications, which ask whether a substance could cause harm under some conditions, rather than whether it does at the amounts people are actually exposed to.) In addition, the National Toxicology Program cites numerous case reports of skin cancer in people using coal-tar preparations to treat skin conditions (2).

In the EU, crude and refined coal tars are prohibited in cosmetic products, with no purity threshold attached (6). In 2000 the EU’s cosmetics committee was asked whether coal tar refined to no more than 0.1 parts per million benzo[a]pyrene could be used at up to 5% in rinse-off hair products (7). The committee concluded that it could not be used safely, because it still contains polycyclic aromatic hydrocarbons that are genotoxic carcinogens, and that it may represent an unacceptably high risk of skin cancer (7).

The safety information described above is specific to coal tar itself. It should not be read as findings about the other ingredients in this category. Those ingredients are fractions distilled out of coal tar; they are chemically related but not identical, they differ in composition, and they may be used in different product formats. None has been assessed individually by a cosmetics safety body in either the EU or the US. Their regulatory status also differs: coal tar is prohibited in the EU outright, while these fractions are prohibited only above set limits for benzene or benzo[a]pyrene content (7).

Why does Credo prohibit coal tar?

Given coal tar’s classification as a carcinogen in humans, it is prohibited in Credo products, as are other fractions distilled out of coal tar. These fractions are also mixtures of many chemicals, which may include genotoxic compounds.

Credo’s approach

Credo’s ingredient restrictions are informed by the Credo Methodology™.

What are cyclic silicones and why are they used in cosmetic and personal care products?

Silicones are group of synthetic ingredients built around the elements silicon and oxygen. They are widely used in cosmetics to improve texture, condition skin and hair, prevent caking, and help dissolve or distribute other ingredients.

Credo does not prohibit all silicones. Linear silicones, such as Dimethicone, can create a smooth texture, temporarily soften the appearance of fine lines, and condition hair. These large, stable molecules are not expected to pose a health risk when used in cosmetics.

However, silicones can persist in the environment. Some people with acne-prone or sensitive skin may also prefer to avoid silicone-containing products if they find certain formulas too occlusive, although silicones are not inherently comedogenic.

Credo prohibits the following cyclic silicones, which have a ring-shaped molecular structure:

• Cyclotetrasiloxane (D4)
• Cyclopentasiloxane (D5)
• Cyclohexasiloxane (D6)
• Cyclomethicone

“Cyclomethicone” is not one specific ingredient. It is a mixture that can contain several cyclic silicones.

The following is referring to cyclic silicones.

What does science say?

The Cosmetic Ingredient Review (CIR) panel has evaluated cyclic silicones for several decades, most recently in 2011 (1–3). The CIR, which evaluates human health rather than environmental effects, concluded that these ingredients were safe under the cosmetic uses and concentrations assessed.

At the time of the review, the maximum reported concentrations were 89% for Cyclomethicone, 28% for D4, 93% for D5, and 48% for D6. These figures describe how the ingredients were being used in 2008; they are not regulatory limits. The CIR’s conclusion was based on the available toxicological evidence and studies showing that very little of these compounds passes through the skin. The panel also concluded that hairsprays did not pose an inhalation risk because the droplets produced were generally too large to travel deeply into the lungs (1).

In the European Union these compounds have been reviewed both for human health and environmental effects. With respect to human health, the EU Scientific Committee on Consumer Safety has reviewed the data for D4 and D5 and similarly concluded that at the exposure amounts expected from cosmetic products, consumers are not a risk (4,5). One notable exception was D5 in hair-styling aerosols and sun-care sprays. The committee concluded that these products could produce airborne concentrations above the level it considered safe.

Separately, the EU classified D4 as a substance suspected of harming reproduction (6). This is a hazard classification: it identifies what a substance may be capable of causing under certain conditions, rather than the risk posed by a particular level of exposure. EU cosmetics law generally prohibits substances classified as carcinogenic, mutagenic, or toxic to reproduction, subject to limited exceptions.

The broader concern with D4, D5, and D6 is their environmental impact. This, not a demonstrated health risk from typical cosmetic use, is the primary reason all three have been restricted in the EU (7). The EU concluded that these compounds have properties of very persistent and very bioaccumulative substances. In other words, they can remain in the environment for a long time and accumulate in living organisms and food chains. D4 was also determined to be toxic to the environment. EU restrictions limit D4, D5, and D6 to trace concentrations in specified cosmetic products, effectively preventing their intentional use as those restrictions take effect.

Why does Credo prohibit cyclic silicones?

Credo prohibits D4, D5, D6, and Cyclomethicone primarily because of their environmental persistence and potential to accumulate in ecosystems.

We also take a precautionary approach when credible evidence indicates a potential long-term health concern and effective alternatives are available. For example, although cosmetic safety assessments generally conclude that exposure to D4 from an individual product is too low to pose a risk, these assessments may not fully capture a person’s combined exposure across multiple products and other sources.

Given the environmental concerns, the reproductive-hazard classification of D4, and the availability of alternatives, Credo does not allow cyclic silicones.

Credo continues to permit linear silicones because they do not present the same level of concern and, for some cosmetic functions, suitable alternatives are not yet widely available.

Credo's approach

Credo's ingredient restrictions are informed by the Credo Methodology™.

What are ethoxylated ingredients and why are they used in cosmetic and personal care products?

Ethoxylated ingredients are a broad class of ingredients produced by reacting a starting material with ethylene oxide, a common manufacturing process known as ethoxylation (1). This process can improve an ingredient's performance by making it more water-soluble, helping oil and water mix, enhancing cleansing, or improving how a product spreads across the skin or hair.

Thousands of cosmetic ingredients are produced using ethoxylation. Common examples include polyethylene glycols (PEGs), polysorbates, sodium laureth sulfate (SLES), ceteareths, and ingredients with names ending in “-eth” (1–3). These ingredients can function as surfactants, emulsifiers, solubilizers, thickeners, and conditioning agents in products ranging from shampoos and cleansers to lotions and creams.

What does science say?

The primary scientific discussion surrounding ethoxylated ingredients is generally not about the finished ingredients themselves, but rather about how they are manufactured.

Ethoxylation uses ethylene oxide, a highly reactive chemical classified as a human carcinogen (4,5). During manufacturing, trace amounts of ethylene oxide may remain in the finished ingredient, and a byproduct called 1,4-dioxane can also be formed (1,3,6). 1,4 dioxane is also classified as a possible human carcinogen (7). Both compounds are considered contaminants rather than intentional ingredients and are not added to cosmetic formulations (8).

Modern manufacturing and purification processes can substantially reduce residual ethylene oxide and 1,4-dioxane (1). Manufacturers and regulators may also test ingredients and finished products to verify that contaminant levels remain very low (9). Regulatory agencies generally do not prohibit ethoxylated ingredients in cosmetics, but they do expect manufacturers to use good manufacturing practices to minimize contaminants whenever technically feasible (9).

Although exposure to residual contaminants from cosmetics is expected to be low, the presence of carcinogenic manufacturing feedstocks and the potential for trace contamination continue to be an area of interest for scientists, regulators, and retailers seeking to reduce avoidable sources of exposure.

Why does Credo prohibit or restrict ethoxylated ingredients?

Ethoxylated ingredients are not all treated the same under The Credo Standard™ as it’s a chemical class of thousands of ingredients with different structures and functions. As a result, Credo evaluates these ingredients as a class based on both their manufacturing process and the availability of safer alternatives, rather than assuming every ethoxylated ingredient presents the same level of concern.

For many common ingredient classes, including sodium laureth sulfate (SLES), ammonium laureth sulfate, PEGs, polysorbates, ceteareths, emulsifying waxes containing ethoxylated ingredients, and other ingredients ending in “-eth,” Credo prohibits their use because suitable non-ethoxylated alternatives are widely available.

For other ethoxylated or alkoxylated ingredients, however, effective alternatives may not yet exist for every cosmetic application. Rather than prohibit these ingredients outright, Credo allows their use only under specific conditions designed to minimize potential contaminant exposure.

Manufacturers must demonstrate that:

• no suitable non-ethoxylated alternative is currently available for the intended function;
• residual ethylene oxide is below 1 ppm;
• 1,4-dioxane contamination in the ingredient is below 10 ppm; and
• finished products containing more than 10% ethoxylated ingredients have analytical testing demonstrating less than 1 ppm 1,4-dioxane.

This approach reflects Credo's broader ingredient philosophy: encouraging the use of alternative chemistries where feasible while applying additional safeguards in situations where ethoxylated ingredients remain necessary.

Credo's approach

Where feasible alternatives exist, Credo favors manufacturing processes that avoid carcinogenic feedstocks. Where alternatives are not yet available, we require additional supplier documentation and analytical testing to help verify that contaminant levels remain as low as reasonably achievable.