Beauty ingredient research

Beauty ingredients explained in plain English

Browse the review database to understand what an ingredient is, what it does in a beauty formula, when it is useful, and when it deserves caution across skincare, haircare, bodycare, makeup, and more.

20769

Reviewed ingredients

524

Low-concern standouts

2884

Need usage caution

Showing 60 of 20,303
AllUV absorberUV filterabrasiveabsorbentacne treatmentactiveactive ingredientadhesivealkalizing agentamino acidanti-aginganti-androgenanti-cavityanti-cavity agentanti-inflammatoryanti-irritantanticariesanticavity agentantidandruffantifungalantimicrobialantioxidantantiperspirantantiplaqueastringentbarrier repairbarrier supportbarrier-repairbarrier-supportbinderbinding agentbiotechbiotechnologybond-builderbotanicalbotanical extractbotanical oilbotanical waterbrighteningbrightening agentbufferbuffering agentcell-communicating ingredientceramidechelating agentchemicalchemical intermediateclaycleansercleansingcleansing agentcolorantconditionerconditioningconditioning agentcooling agentcosmeticcosmetic additivecosmetic colorantcosmetic ingredientcosmetic pigmentcosmetic powdercosmetic-texturizercosmetic-waxcosmeticscrosslinking agentdelivery agentdelivery systemdenaturantdeodorantdeodorant agentdepigmenting agentdepilatorydepilatory agentdesensitizing agentdyedye intermediatedye precursordye-intermediateemollientemulsifierenzymeessential oilexfoliantexperimentaleyelashfermentfilm formerfilm-formerfilm-formingfilm-forming agentfirming agentfixativeflavoring agentformulationfragrancefragrance ingredientfunctional ingredientgashair carehair colorhair coloranthair conditionerhair dyehair removalhair-carehair-colorhaircarehumectantindustrialinsecticideintermediatelashlash carelash enhancerlash-and-browlip carelipidmakeupmarine extractmasking agentmicrobiomemicrobiome modulatormineralmoisturizernail carenail-careocclusiveoilopacifieropacifying agentoptical agentoral careotheroxidative dyeoxidative dye precursoroxidizing agentpH adjusterpain reliefpenetration enhancerpeptidepersonal careph adjusterpharmaceuticalpheromonepigmentplant oilplasticizerpolymerpolymer precursorprebioticprescription-drugpreservativepreservative boosterprobioticprocessing agentprocessing aidpropellantproteinpurifyingreducing agentretinoidscalp caresebum regulatorsebum-regulatorself-tannerself-tanningsensory additivesensory agentsensory modifiersiliconeskin barrierskin barrier supportskin conditionerskin conditioningskin conditioning agentskin lighteningskin protectantskin-conditioningskin-conditioning agentskin-identicalskin-identical ingredientskin-lighteningskin-lightening agentskincaresolventsoothingsoothing agentstabilizerstimulantsunscreensurfactantsyntheticsynthetic colorantsynthetic dyesynthetic resinsynthetic-coloranttexture enhancertexturizerthickenertoneruv-absorberuv-filtervasoactivevasodilatorviscosity controlviscosity controllingviscosity controlling agentvitaminwax

Thickener

Methylamido Cellulose Gum

Methylamido Cellulose Gum

3.8

A gentle, plant-derived thickener that improves product texture without common irritation concerns.

Irritation

low

Source

semi-synthetic

beautyskincarethickener
Read ingredient review

Fragrance Ingredient

Methylbenzyl Acetate

METHYLBENZYL ACETATE

3.5

Methylbenzyl Acetate is a common synthetic fragrance component that adds a sweet floral note, but it may cause allergic reactions in sensitive individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Preservative

Methylbenzyl Alcohol

METHYLBENZYL ALCOHOL

3.8

A gentle preservative booster and fragrance component that helps keep products fresh, but may cause mild irritation in very sensitive skin.

Irritation

low

Source

synthetic

beautyskincarepreservativefragrance
Read ingredient review

Fragrance Ingredient

Methylbenzyl Carbinyl Acetate

METHYLBENZYL CARBINYL ACETATE

3.5

A synthetic floral scent ingredient that is generally safe at low levels but may cause sensitivity in those with fragrance allergies.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

UV Filter

Methylbenzylidene Camphor

METHYLENEDIOXYBENZOYL ETHYL PABA

3.5

A synthetic UVB filter that is effective but has limited global approval due to safety concerns.

Irritation

low

Source

synthetic

beautyskincaresunscreen
Read ingredient review

Fragrance Ingredient

Methylbicycloheptylpropyl Acetate

METHYLBICYCLOHEPTYLPROPYL ACETATE

3.5

A synthetic scent ingredient that adds a pleasant aroma but offers no skincare benefits; safe for most people at low levels.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

UV Filter

Methylbutylphenyl Hexyloxybenzoate

METHYLBUTYLPHENYL HEXYLOXYBENZOATE

4.0

A synthetic UV filter that effectively absorbs UV rays, but its use is limited to certain regions due to regulatory differences.

Irritation

low

Source

synthetic

beautyskincaresunscreen
Read ingredient review

UV Filter

Methylbutylphenyl Octyloxybenzoate

METHYLBUTYLPHENYL OCTYLOXYBENZOATE

4.0

A synthetic UV filter that helps protect skin from sun damage, generally considered safe and effective in approved concentrations.

Irritation

low

Source

synthetic

beautyskincaresunscreen
Read ingredient review

Solvent

Methylbutylphenyl Pentylbenzoate

METHYLBUTYLPHENYL PENTYLBENZOATE

4.0

A synthetic ester that helps dissolve and stabilize UV filters in sunscreens, generally considered safe and non-irritating.

Irritation

low

Source

synthetic

beautyskincaresunscreen
Read ingredient review

Emollient

Methylbutylphenyl Propylbenzoate

METHYLBUTYLPHENYL PROPYLBENZOATE

4.0

A lightweight, non-greasy emollient that helps products spread smoothly and leaves skin feeling soft without clogging pores.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Thickener

Methylcellulose

Methylcellulose

4.0

A gentle, plant-derived thickener that improves product texture without clogging pores or irritating skin.

Irritation

low

Source

semi-synthetic

beautyskincaretexturizer
Read ingredient review

Preservative

Methylchloroisothiazolinone

METHYLCHLOROISOTHIAZOLINONE

2.5

A powerful preservative that is a common contact allergen; best avoided by those with sensitive skin.

Irritation

high

Source

synthetic

beautyskincarepreservative
Read ingredient review

Fragrance Ingredient

Methylcinnamonitrile

Methylcinnamonitrile

3.5

Methylcinnamonitrile is a synthetic fragrance compound that adds a cinnamon-like scent but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Methylcinnamyl Alcohol

METHYLCINNAMYL ALCOHOL

3.5

Methylcinnamyl alcohol is a synthetic fragrance ingredient that provides a floral scent but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Antioxidant

Methylcyclohexanedione

METHYLCYCLOHEXANEDIONE

3.5

Methylcyclohexanedione is a synthetic antioxidant that helps protect products from oxidation, but its benefits for skin are not well-studied.

Irritation

low

Source

synthetic

beautyskincareantioxidant
Read ingredient review

Fragrance Ingredient

Methylcyclohexenyl Butanol

METHYLCYCLOHEXENYL BUTANOL

3.5

A synthetic scent ingredient that adds a floral note but offers no skincare benefit and may be a concern for those avoiding fragrance.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Methylcyclohexenylpropyl Cyclopentanone

METHYLCYCLOHEXENYLPROPYL CYCLOPENTANONE

3.5

A synthetic fragrance compound that adds a pleasant floral note but offers no skincare benefit and may be a concern for those with fragrance sensitivities.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Methylcyclopentenolone

METHYLCYCLOPENTENOLONE

3.5

A synthetic scent ingredient that adds a warm, sweet note to cosmetics but offers no skin benefit.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Methylcyclotridecanone

METHYLCYCLOTRIDECANONE

3.5

A synthetic musk used for scent; generally safe at low levels but may cause irritation in sensitive individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

Methyldihydrojasmonate

METHYLDIHYDROJASMONATE

4.0

A widely used synthetic fragrance that adds a pleasant jasmine-like scent to products, with a low risk of irritation for most people.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Antioxidant

Methylene Di-T-Butylcresol

METHYLENE DI-T-BUTYLCRESOL

4.0

A reliable synthetic antioxidant that protects product freshness but offers minimal direct skin benefit.

Irritation

low

Source

synthetic

beautyskincareantioxidant
Read ingredient review

Preservative

Methylene Glycol

METHYLENE GLYCOL

2.5

Methylene glycol is a controversial preservative that releases formaldehyde; it is effective but can cause irritation and is best avoided by sensitive individuals.

Irritation

high

Source

synthetic

beautyskincarepreservative
Read ingredient review

Fragrance Ingredient

Methylenedioxyphenyl Methylpropanal

METHYLENEDIOXYPHENYL METHYLPROPANAL

3.5

A common synthetic fragrance ingredient that adds a floral-spicy note but can be a skin sensitizer for some people.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

pH Adjuster

Methylethanolamine

Methylethanolamine

3.5

Methylethanolamine is a synthetic pH adjuster that helps balance product acidity, but it can be a skin irritant at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincarepH adjuster
Read ingredient review

Skin conditioner

Methyleugenyl PEG-8 Dimethicone

METHYLEUGENYL PEG-8 DIMETHICONE

3.5

A gentle silicone derivative that smooths skin and hair without heavy buildup, but its methyleugenol component warrants caution for sensitive individuals.

Irritation

low

Source

semi-synthetic

beautyskincarehaircare
Read ingredient review

Antioxidant

Methylfurfural

METHYLFURFURAL

3.5

Methylfurfural is a natural antioxidant compound with limited research in skincare; it may offer some protective benefits but can be irritating at high levels.

Irritation

moderate

Source

natural

beautyskincareantioxidant
Read ingredient review

pH Adjuster

Methylglucamine HCl

METHYLGLUCAMINE HCL

4.0

A gentle pH adjuster that helps keep your skincare products stable and comfortable on the skin.

Irritation

low

Source

semi-synthetic

beautyskincarepH adjuster
Read ingredient review

Fragrance Ingredient

Methylheptadienone

METHYLHEPTADIENONE

3.5

Methylheptadienone is a synthetic fragrance compound that adds a fresh scent but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance ingredient

Methylheptanone

METHYL HEPTYL KETONE

3.5

Methylheptanone is a synthetic fragrance ingredient that adds a fruity, banana-like scent to products, but it offers no skincare benefits and may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Methylheptenone Isomers

Methylheptenone Isomers

3.5

Methylheptenone Isomers are synthetic scent ingredients that add a fresh note to products but may cause irritation for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Emollient

Methylheptyl Isostearate

METHYLHEPTYL ISOSTEARATE

4.0

A lightweight synthetic emollient that softens skin without a greasy feel, generally well-tolerated.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Emollient

Methylheptyl Laurate

Methylheptyl Laurate

4.0

A lightweight, non-greasy emollient that helps skin feel soft and smooth without clogging pores.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Emollient

Methylheptyl Myristate

METHYLHEPTYL MYRISTATE

4.0

A lightweight synthetic emollient that softens skin without a greasy feel, generally well-tolerated and non-comedogenic.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Emollient

Methylheptyl Palmitate

METHYLHEPTYL PALMITATE

4.0

A lightweight synthetic emollient that softens skin without clogging pores, ideal for oily or combination skin types.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Fragrance Ingredient

Methylhexylacetaldehyde

METHYLHEXYLACETALDEHYDE

3.5

A synthetic fragrance compound that adds a pleasant floral-green note, but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Humectant

Methylhydantoin-Imide

1-METHYLHYDANTOIN-2-IMIDE

3.5

A synthetic humectant that helps skin retain moisture, but research on its long-term effects is still limited.

Irritation

low

Source

synthetic

beautyskincarehumectant
Read ingredient review

Preservative

Methylisothiazolinone

Methylisothiazolinone

2.5

A powerful but controversial preservative that is a common allergen; many prefer to avoid it.

Irritation

high

Source

synthetic

beautyskincarepreservative
Read ingredient review

Skin conditioning

Methylmethionine

METHYLMETHIONINE

3.8

Methylmethionine is a gentle, soothing amino acid derivative that may help calm irritation and support skin barrier function, though research is still emerging.

Irritation

low

Source

semi-synthetic

beautyskincareconditioning agent
Read ingredient review

Fragrance

Methylnaphthalenone

3,4-Dihydro-6-methylnaphthalenone

3.5

A synthetic fragrance ingredient with limited research; generally considered safe at low levels but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Emollient

Methyloctanediyl Diacetate

METHYLOCTANEDIYL DIACETATE

3.8

A lightweight synthetic emollient that helps soften skin without a greasy feel, generally well-tolerated.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Fragrance Ingredient

Methyloctenol

METHYLOCTENOL

3.5

Methyloctenol is a synthetic scent ingredient that adds a fresh note but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

Methyloctenyl Acetate

METHYLOCTENYL ACETATE

3.5

Methyloctenyl Acetate is a synthetic fragrance ingredient that adds a fresh, fruity scent but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance component

Methyloctyl Acetaldehyde

METHYLOCTYL ACETALDEHYDE

3.5

A synthetic scent ingredient that adds a fresh note but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Antioxidant

Methyloxopropoxy-Pyranone

2-Methyl-3-oxopropoxy-pyran-4-one

3.5

A synthetic antioxidant that helps stabilize formulas, but research on its skin benefits is limited.

Irritation

low

Source

synthetic

beautyskincareantioxidant
Read ingredient review

Preservative

Methylparaben

METHYLPARABEN

3.5

Methylparaben is an effective, low-irritation preservative, but some consumers avoid it due to concerns about endocrine disruption.

Irritation

low

Source

synthetic

beautyskincarepreservative
Read ingredient review