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

Emollient

1-Methyldecyl Acetate

1-METHYLDECYL ACETATE

3.5

A gentle synthetic ester that softens skin and improves product texture, with low irritation potential.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Fragrance Ingredient

1-Nonen-3-ol

1-NONEN-3-OL

3.5

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

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

1-Penten-3-ol

1-PENTEN-3-OL

3.5

A synthetic fragrance compound that adds a fresh, green scent but may cause irritation in sensitive individuals at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Humectant

1,10-Decanediol

1,10-DECANEDIOL

4.0

A gentle humectant that helps hydrate skin and improve product texture without common irritation.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

1,2-Hexanediol

1,2-Hexanediol

4.0

A gentle, multifunctional ingredient that helps keep products fresh and your skin hydrated without irritation.

Irritation

low

Source

synthetic

beautyskincarepreservativehumectant
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Solvent

1,4-Butanediol

1,4-BUTANEDIOL

3.5

A synthetic solvent that helps other ingredients dissolve and spread, but offers no direct skin benefit.

Irritation

low

Source

synthetic

beautyskincaresolvent
Read ingredient review

Antioxidant

1,5-Naphthalenediol

1,5-NAPHTHALENEDIOL

3.5

1,5-Naphthalenediol is a synthetic antioxidant and color stabilizer, but its use in cosmetics is limited and safety data is sparse.

Irritation

moderate

Source

synthetic

beautyskincareantioxidant
Read ingredient review

Humectant

1,5-Pentanediol

Pentylene Glycol

4.0

A gentle, effective humectant that also helps preserve your products without the sting of traditional preservatives.

Irritation

low

Source

synthetic

beautyskincarehumectant
Read ingredient review

Fragrance

10-Hydroxy-1,8-p-Menthadiene

10-HYDROXY-1,8-P-MENTHADIENE

3.5

A fragrant compound from mint oils that adds a fresh scent but may cause irritation in sensitive individuals.

Irritation

moderate

Source

natural

beautyskincarefragrance
Read ingredient review

Soothing Agent

10-Hydroxydecanoic Acid

10-HYDROXYDECANOIC ACID

4.0

A gentle, naturally derived fatty acid that helps calm and condition the skin, with emerging research supporting its soothing benefits.

Irritation

low

Source

natural

beautyskincaresoothing agent
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Antioxidant

10-Hydroxydecenoic Acid

10-HYDROXYDECENOIC ACID

4.0

A gentle, naturally derived fatty acid that helps soothe and protect the skin, often found in royal jelly-based products.

Irritation

low

Source

natural

beautyskincareantioxidant
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Exfoliant

10-Hydroxystearic Acid

10-HYDROXYSTEARIC ACID

4.0

A gentle, non-irritating exfoliating acid that helps smooth skin texture without the sting of stronger acids.

Irritation

low

Source

semi-synthetic

beautyskincareexfoliant
Read ingredient review

Fragrance Ingredient

10-Undecenyl Acetate

10-UNDECENYL ACETATE

3.5

A synthetic fragrance ingredient that adds a pleasant scent but offers no skincare benefits; generally safe at low levels.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-(1-Ethylpropyl)pyridine

2-(1-ETHYLPROPYL)PYRIDINE

2.0

A synthetic fragrance compound with limited safety data; best avoided by those with sensitive skin or fragrance allergies.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Acetonaphthone

2-ACETONAPHTHONE

3.0

2-Acetonaphthone is a synthetic fragrance ingredient with limited safety data; it is generally considered safe at low levels but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Benzylheptanol

2-BENZYLHEPTANOL

3.5

2-Benzylheptanol is a synthetic fragrance ingredient that adds a pleasant scent to products; it is generally considered safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

2-Decenal

2-DECENAL

3.5

2-Decenal is a synthetic fragrance ingredient that adds a fresh citrus note but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

2-Dodecenol

2-DODECENOL

3.5

2-Dodecenol is a synthetic fatty alcohol used for scent and preservation, but it may cause irritation in sensitive individuals at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Solvent

2-Ethylbutanol

2-ETHYLBUTANOL

2.5

A synthetic alcohol used as a solvent or denaturant; can be drying or irritating for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
Read ingredient review

Fragrance Ingredient

2-Ethylbutyric Acid

2-Ethylbutyric Acid

3.0

A synthetic fragrance ingredient that adds a fruity, cheesy scent but offers no direct skincare benefit and may irritate sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Solvent

2-Ethylhexanol

2-ETHYLHEXANOL

2.5

A synthetic solvent used in small amounts; not a star ingredient but generally safe at low concentrations.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
Read ingredient review

Fragrance

2-Ethylidenedecanal

2-ETHYLIDENEDECANAL

3.5

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

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

2-Heptanol

2-HEPTANOL

3.5

2-Heptanol is a synthetic fragrance ingredient that adds scent but offers no skincare benefits and may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

2-Hexanol

2-HEXANOL

3.5

2-Hexanol is a synthetic fragrance ingredient that adds scent to products but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Film Former

2-Hydroxyethyl Acrylate

2-HYDROXYETHYL ACRYLATE

2.5

2-Hydroxyethyl acrylate is a synthetic raw material used to create polymers that improve product texture and stability, but it is rarely found as a standalone ingredient in consumer products.

Irritation

moderate

Source

synthetic

beautyskincarefilm-former
Read ingredient review

Fragrance Ingredient

2-Isopentenal

2-ISOPENTENAL

2.5

2-Isopentenal is a synthetic fragrance compound with limited safety data; it may cause skin irritation in sensitive individuals and is best avoided in leave-on products for reactive skin.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-M-Cresylethanol

2-M-CRESYLETHANOL

3.5

2-M-Cresylethanol is a synthetic fragrance ingredient with mild antimicrobial properties, but it may cause skin irritation in sensitive individuals at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Skin conditioning agent

2-Melozol Acetate

2-Melozol Acetate

2.5

2-Melozol Acetate is a little-known synthetic ingredient with limited research; its benefits and safety are not well-established, so approach with caution.

Irritation

low

Source

synthetic

beautyskincareconditioning agent
Read ingredient review

Antioxidant

2-Melozol Formate

2-Melozol Formate

3.5

2-Melozol Formate is a little-known synthetic antioxidant that may help protect skin from environmental stress, but research is very limited.

Irritation

low

Source

synthetic

beautyskincareantioxidant
Read ingredient review

Fragrance

2-Methoxy-p-Cresol

2-METHOXY-P-CRESOL

3.5

2-Methoxy-p-Cresol is a synthetic fragrance ingredient that adds a smoky, spicy note to products, but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methyl 5-Phenylpentanol

2-METHYL 5-PHENYLPENTANOL

3.5

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

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Solvent

2-Methyl-2-Butenol

2-METHYL-2-BUTENOL

3.0

A small alcohol molecule used mainly as a solvent or fragrance ingredient; it has limited direct skin benefit and may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
Read ingredient review

Fragrance Ingredient

2-Methyl-3-Buten-2-ol

2-METHYL-3-BUTEN-2-OL

3.5

A synthetic fragrance ingredient that adds a fresh, floral scent but offers no skincare benefits and may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylbutane-2-Thiol

2-Methylbutane-2-Thiol

2.0

A potent synthetic odorant rarely used in skincare; its strong sulfurous smell limits its appeal and may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Solvent

2-Methylbutanol

2-METHYLBUTANOL

3.0

2-Methylbutanol is a small alcohol used to dissolve other ingredients or add scent, but it can be drying or irritating for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
Read ingredient review

Fragrance Ingredient

2-Methylbutyl Butyrate

2-Methylbutyl Butyrate

3.8

A fruity-smelling ester used to add a pleasant apple-like scent to products; generally considered safe at low concentrations but may cause irritation in sensitive individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylbutyl Isovalerate

2-METHYLBUTYL ISOVALERATE

3.5

A synthetic ester that adds a fruity, floral scent to products; generally considered safe at low levels but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylbutyraldehyde

2-METHYLBUTYRALDEHYDE

3.5

A synthetic scent ingredient that adds a warm, nutty aroma but offers no skincare benefit and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylbutyric Acid

2-METHYLBUTYRIC ACID

3.5

A natural fatty acid used mainly for its cheesy or fruity scent; safe at low levels but not a functional skincare active.

Irritation

low

Source

natural

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methyldodecanal

2-METHYLDODECANAL

3.5

A synthetic scent ingredient that adds a fresh, citrusy note but offers no skincare benefits and may be a concern for those with fragrance sensitivities.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylfuran-3-Thiol

2-METHYLFURAN-3-THIOL

3.0

A synthetic fragrance compound used in tiny amounts to add a savory or roasted note; generally considered safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylpent-2-Enoic Acid

2-METHYLPENT-2-ENOIC ACID

3.5

A synthetic fragrance ingredient that adds a fruity, acidic scent but may cause irritation in sensitive individuals at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylpent-2-enyl Acetate

2-METHYLPENT-2-ENYL ACETATE

3.5

A synthetic fragrance ester that adds a fruity or floral note but offers no skincare benefit beyond scent.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylpent-3-Enoic Acid

2-METHYLPENT-3-ENOIC ACID

3.5

A synthetic fragrance ingredient that adds scent but offers no skin benefit and may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Methylpentyl 2-Methylvalerate

2-METHYLPENTYL 2-METHYLVALERATE

3.5

A synthetic fragrance ester that adds a pleasant scent but offers no skincare benefits; safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Tyrosinase Inhibitor

2-Methylresorcinol

2-METHYLRESORCINOL

4.0

A potent synthetic brightener that targets dark spots and uneven tone, but can be irritating for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarebrightening
Read ingredient review

Fragrance Ingredient

2-Nonylcrotonaldehyde

2-Nonylcrotonaldehyde

3.5

A synthetic fragrance aldehyde that adds a fresh, green scent but can be a skin sensitizer for some people.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Preservative

2-o-Cresylethanol

2-O-CRESYLETHANOL

3.5

A synthetic preservative booster that helps keep products fresh but may cause irritation for sensitive skin at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincarepreservative
Read ingredient review

Solvent

2-Octanol

2-OCTANOL

3.8

2-Octanol is a mild fatty alcohol that helps dissolve other ingredients and can boost preservative effectiveness, but it's not a primary active ingredient.

Irritation

low

Source

synthetic

beautyskincaresolvent
Read ingredient review

Fragrance Ingredient

2-Octenal

2-OCTENAL

3.5

2-Octenal is a synthetic fragrance compound that adds a fresh, green scent but can be a skin sensitizer for some people.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-P-Cresylethanol

2-P-CRESYLETHANOL

3.5

2-P-Cresylethanol is a synthetic fragrance ingredient with mild preservative-boosting properties, generally considered safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Solvent

2-Pentanol

2-PENTANOL

2.5

2-Pentanol is a solvent alcohol that can help dissolve other ingredients but may be drying or irritating for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
Read ingredient review

Fragrance

2-Phenylpropylpyridine

2-PHENYLPROPYLPYRIDINE

3.5

A synthetic fragrance ingredient with limited safety data; generally considered low risk at typical use levels but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-sec-Butylcyclohexanone

2-SEC-BUTYLCYCLOHEXANONE

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

Fragrance Ingredient

2-T-Butylcyclohexyl Acetate

2-T-BUTYLCYCLOHEXYL ACETATE

3.5

A synthetic scent ingredient that adds a pleasant fruity-woody note but offers no skincare benefits and may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

2-T-Butylcyclohexyloxybutanol

2-T-BUTYLCYCLOHEXYLOXYBUTANOL

3.8

A synthetic cooling agent that adds a refreshing feel but may irritate sensitive skin at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Tert-Butyl-4-Methylcyclohexanol

2-TERT-BUTYL-4-METHYLCYCLOHEXANOL

3.5

A synthetic cooling and minty fragrance ingredient that can add a pleasant sensation but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

2-Tert-Butylcyclohexanol

2-TERT-BUTYLCYCLOHEXANOL

3.8

A synthetic cooling agent that adds a fresh, minty scent to products; generally well-tolerated but may cause irritation in sensitive individuals at high levels.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review