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

Fragrance

Culilawan Leaf Oil

Cinnamomum culilawan leaf oil

3.5

Culilawan leaf oil adds a warm, spicy scent to products but may irritate sensitive skin, especially at high concentrations.

Irritation

moderate

Source

natural

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Antioxidant

Culilawan Wood Extract

Cinnamomum Culilawan Wood Extract

3.5

A fragrant wood extract with antioxidant potential, but limited research and a moderate risk of skin irritation.

Irritation

moderate

Source

natural

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Antioxidant

Cumin Fruit Extract

Cuminum Cyminum Fruit Extract

3.8

Cumin Fruit Extract offers antioxidant benefits and mild soothing effects, but research on its topical use is still limited.

Irritation

low

Source

natural

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Exfoliant

Cumin Seed Powder

Cuminum Cyminum Seed Powder

3.8

Cumin Seed Powder offers gentle physical exfoliation and antioxidant benefits, but its evidence in skincare is still emerging and it may cause irritation for very sensitive skin.

Irritation

low

Source

natural

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Fragrance

Cuminaldehyde

CUMINALDEHYDE

3.5

Cuminaldehyde is a natural fragrance compound from cumin oil that adds a warm, spicy scent but can be a skin sensitizer for some people.

Irritation

moderate

Source

natural

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Fragrance Ingredient

Cuminyl Acetate

CUMINYL ACETATE

3.5

Cuminyl acetate is a synthetic fragrance compound that adds a warm, spicy note to products, but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
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Fragrance Ingredient

Cuminyl Nitrile

CUMINYL NITRILE

3.5

Cuminyl nitrile is a synthetic fragrance ingredient that adds a warm, spicy scent but offers no skincare benefits and may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
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Antioxidant

Cundurango Root Extract

Marsdenia Cundurango Root Extract

3.8

Cundurango Root Extract is a gentle botanical with antioxidant and soothing potential, but research on its cosmetic benefits is still limited.

Irritation

low

Source

natural

beautyskincarebotanical extract
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Fragrance

Cunila Galioides Oil

CUNILA GALIOIDES FLOWER/LEAF OIL

3.5

A fragrant essential oil with limited research; best for those who enjoy natural scents but may cause irritation in sensitive skin.

Irritation

moderate

Source

natural

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Emollient

Cuphea Seed Oil

CUPHEA LANCEOLATA/VISCOSISSIMA SEED OIL

4.0

A lightweight, non-greasy plant oil that hydrates and softens skin without clogging pores—great for oily or combination skin types.

Irritation

low

Source

natural

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Antioxidant

Cupric Acetate

Cupric Acetate

3.5

Cupric acetate is a copper salt that may offer antioxidant benefits, but it is used in very low concentrations and can be irritating for sensitive skin.

Irritation

moderate

Source

synthetic

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Antioxidant

Cupric Chloride

Cupric Chloride

3.5

Cupric chloride is a copper compound that may support skin repair and antioxidant defense, but it is used in tiny amounts and can be irritating at higher levels.

Irritation

moderate

Source

synthetic

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Antimicrobial

Cuprous Oxide

CUPROUS OXIDE

3.5

Cuprous oxide offers antimicrobial benefits but may cause irritation in sensitive skin; it's not a common everyday ingredient.

Irritation

moderate

Source

natural

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Emollient

Cupuacu Butter

THEOBROMA GRANDIFLORUM SEED BUTTER

4.3

A deeply nourishing plant butter that hydrates and softens skin without feeling greasy, ideal for dry or sensitive skin.

Irritation

low

Source

natural

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Emollient

Cupuaçu Butter Extract

THEOBROMA GRANDIFLORUM SEED BUTTER EXTRACT

4.3

A deeply nourishing plant butter that hydrates and softens skin without feeling greasy.

Irritation

low

Source

natural

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Emollient

Cupuaçu Butter Glycerides

THEOBROMA GRANDIFLORUM SEED BUTTER GLYCERIDES

4.0

A gentle, semi-synthetic emollient derived from cupuaçu butter that softens skin without clogging pores.

Irritation

low

Source

semi-synthetic

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Emollient

Cupuaçu Butter Glyceryl Esters

THEOBROMA GRANDIFLORUM SEED BUTTER GLYCERYL ESTERS

4.3

A gentle, semi-synthetic emollient derived from cupuaçu butter that softens and smooths skin without clogging pores.

Irritation

low

Source

semi-synthetic

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Emollient

Cupuacu Butter PEG-8 Esters

THEOBROMA GRANDIFLORUM SEED BUTTER PEG-8 ESTERS

4.0

A gentle, water-friendly emollient that brings the richness of cupuacu butter into lightweight, rinse-off and leave-on products.

Irritation

low

Source

semi-synthetic

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Emollient

Cupuacu Butter Polyglyceryl-6 Esters

THEOBROMA GRANDIFLORUM SEED BUTTER POLYGLYCERYL-6 ESTERS

4.3

A gentle, non-greasy emollient derived from cupuacu butter that helps soften and smooth skin without clogging pores.

Irritation

low

Source

semi-synthetic

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Antioxidant

Cupuaçu Fruit Extract

THEOBROMA GRANDIFLORUM FRUIT EXTRACT

4.0

A gentle, antioxidant-rich fruit extract that helps soothe and hydrate skin without irritation.

Irritation

low

Source

natural

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Humectant

Cupuacu Fruit Juice

THEOBROMA GRANDIFLORUM FRUIT JUICE

4.0

A gentle, hydrating fruit juice rich in antioxidants that helps soothe and moisturize the skin without clogging pores.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Antioxidant

Cupuacu Fruit Juice Powder

THEOBROMA GRANDIFLORUM FRUIT JUICE POWDER

4.0

A gentle, antioxidant-rich fruit powder that helps hydrate and protect skin from environmental stress.

Irritation

low

Source

natural

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Exfoliant

Cupuaçu Seed Powder

THEOBROMA GRANDIFLORUM SEED POWDER

4.0

Cupuaçu seed powder offers gentle physical exfoliation plus antioxidant benefits, making it a soothing alternative to harsher scrubs.

Irritation

low

Source

natural

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Emulsifier

Cupuacu Seedate

Sorbitan Theobroma Grandiflorum Seedate

4.0

A gentle, plant-based emulsifier that helps stabilize creams and leaves skin feeling soft without clogging pores.

Irritation

low

Source

natural

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Fragrance

Curassavian Orange Peel Oil

Citrus Aurantium Curassuviensis Peel Oil

3.8

A fragrant citrus oil that can add a fresh scent and mild antioxidant benefits, but may irritate sensitive or sun-exposed skin.

Irritation

moderate

Source

natural

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Fragrance

Curcuma Zedoaria Root Oil

CURCUMA ZEDOARIA ROOT OIL

3.8

A fragrant essential oil with antioxidant potential, but limited research and a moderate risk of skin irritation for sensitive types.

Irritation

moderate

Source

natural

beautyskincareessential oil
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Antioxidant

Curcuma Zedoaria Root Water

Curcuma Zedoaria Root Water

3.8

A gentle, antioxidant-rich water from white turmeric that may help calm skin and fight free radicals, but research is still early.

Irritation

low

Source

natural

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Antioxidant

Curcumin

Curcumin

3.8

Curcumin is a potent antioxidant from turmeric that may help calm redness and protect skin from environmental stress, but its bright yellow color can stain skin and fabrics.

Irritation

low

Source

natural

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Antioxidant

Curcuminyl Glutaroyl Tripeptide-7

CURCUMINYL GLUTAROYL TRIPEPTIDE-7

4.0

A hybrid ingredient that pairs curcumin's antioxidant power with a peptide to calm and brighten skin, though research is still early.

Irritation

low

Source

semi-synthetic

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Soothing Agent

Curly Mint Leaf Extract

Mentha Spicata Crispa Herb Extract

3.8

Curly Mint Leaf Extract is a gentle botanical that may help calm skin and provide antioxidant protection, but research on its cosmetic benefits is still limited.

Irritation

low

Source

natural

beautyskincarebotanical extract
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Fragrance

Curry Leaf Oil

MURRAYA KOENIGII LEAF OIL

3.8

Curry Leaf Oil offers antioxidant benefits and a distinctive scent, but its fragrance components may irritate sensitive skin.

Irritation

moderate

Source

natural

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Antioxidant

Curry Leaf Stem Extract

MURRAYA KOENIGII STEM EXTRACT

3.8

A gentle, antioxidant-rich plant extract that may help protect skin from environmental stress, though research is still early.

Irritation

low

Source

natural

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Colorant

Curry Red

Curry Red

3.8

A natural red colorant from annatto seeds, generally safe for most skin types but may cause rare allergic reactions.

Irritation

low

Source

natural

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Soothing agent

Cusparia Bark Extract

CUSPARIA FEBRIFUGA BARK EXTRACT

3.8

A gentle botanical extract with antioxidant and soothing potential, though research is limited and it's best used as part of a broader formulation.

Irritation

low

Source

natural

beautyskincarebotanical extract
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Antioxidant

Custard Apple Juice

ANONA RETICULATA JUICE

3.5

A gentle, antioxidant-rich fruit juice that may help soothe and protect skin, but research is limited.

Irritation

low

Source

natural

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Antioxidant

Cyanobacteria Extract

ANABAENA FLOSAQUAE/APHANIZOMENON FLOSAQUAE/COELOSPHAERIUM KUETZINGIANUM/MICROCYSTIS AERUGINOSA/OSCILLATORIA PRINCEPS EXTRACT

3.8

A blend of cyanobacteria (blue-green algae) that may offer antioxidant and soothing benefits, but research on this specific mix is limited.

Irritation

low

Source

natural

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Soothing Agent

Cyanocobalamin

Cyanocobalamin

4.0

Cyanocobalamin is a gentle, synthetic vitamin B12 that helps calm redness and support skin barrier function, making it a good option for sensitive or irritated skin.

Irritation

low

Source

synthetic

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Soothing Agent

Cyanotis Arachnoidea Root Extract

Cyanotis Arachnoidea Root Extract

4.0

A gentle, plant-derived extract that may help calm irritated skin and provide antioxidant support, though research is still emerging.

Irritation

low

Source

natural

beautyskincaresoothing agent
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Antioxidant

Cyathea Cumingii Leaf Extract

CYATHEA CUMINGII LEAF EXTRACT

3.8

A gentle, antioxidant-rich fern extract that may help calm skin and fight free radicals, though research is still early.

Irritation

low

Source

natural

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Antioxidant

Cyathusal A

Cyathusal A

3.5

Cyathusal A is a plant compound with early research suggesting antioxidant and anti-inflammatory benefits, but it is not yet widely studied or common in commercial skincare.

Irritation

low

Source

natural

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Antioxidant

Cyathusal B

Cyathusal B

3.5

Cyathusal B is an emerging fungal-derived antioxidant with early research suggesting anti-inflammatory benefits, but human studies are lacking.

Irritation

low

Source

natural

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Anti-Aging Agent

Cyathusal C

Cyathusal C

4.0

Cyathusal C is a synthetic peptide that may help reduce fine lines and improve skin firmness, but research is still emerging.

Irritation

low

Source

synthetic

beautyskincareanti-aging
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Fragrance Ingredient

Cyclamen Aldehyde

CYCLAMEN ALDEHYDE

3.5

Cyclamen Aldehyde is a synthetic floral scent that can cause skin irritation or allergies in sensitive individuals, especially at higher concentrations.

Irritation

moderate

Source

synthetic

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Fragrance Ingredient

Cyclamen Aldehyde Acetal

CYCLAMEN ALDEHYDE ETHYLENEGLYCOL CYCLIC ACETAL

3.5

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

Irritation

moderate

Source

synthetic

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Fragrance Ingredient

Cyclamen Aldehyde Diethyl Acetal

CYCLAMEN ALDEHYDE DIETHYL ACETAL

3.5

A synthetic floral scent ingredient that adds a pleasant fragrance but may cause skin sensitivity in some people.

Irritation

moderate

Source

synthetic

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Antioxidant

Cyclanthera Pedata Fruit Extract

CYCLANTHERA PEDATA FRUIT EXTRACT

3.8

A gentle, antioxidant-rich fruit extract that may help calm skin and fight environmental stress, though research is still limited.

Irritation

low

Source

natural

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Cell-communicating agent

Cyclic GMP

Sodium Guanine Cyclic Monophosphate

3.8

A cell-signaling molecule that may help strengthen the skin barrier and improve hydration, but research is still early.

Irritation

low

Source

synthetic

beautyskincarecell-communicating ingredient
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Fragrance

Cyclized Lemon Eucalyptus Oil

CYCLIZED EUCALYPTUS CITRIODORA LEAF/TWIG OIL

3.8

A processed lemon eucalyptus oil used mainly for scent; may offer mild skin conditioning but poses a moderate risk of irritation for sensitive skin.

Irritation

moderate

Source

natural

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Humectant

Cyclo PEG-6

CYCLO PEG-6

3.5

A gentle synthetic humectant that helps hydrate skin and improve product texture, but offers no unique benefits over more common alternatives.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Skin conditioning agent

Cyclocarboxypropyloleic Acid

CYCLOCARBOXYPROPYLOLEIC ACID

4.0

A synthetic lipid that mimics natural skin fats to support the moisture barrier, with early research suggesting it may help reduce water loss and improve skin comfort.

Irritation

low

Source

synthetic

beautyskincareemollient
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Antioxidant

Cyclocarya Paliurus Leaf Extract

CYCLOCARYA PALIURUS LEAF EXTRACT

3.8

A gentle, plant-derived antioxidant that may help protect skin from environmental stress, though research is still early and mostly lab-based.

Irritation

low

Source

natural

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Stabilizer

Cyclodextrin

Cyclodextrin

4.0

Cyclodextrin is a gentle, sugar-based molecule that helps stabilize and deliver active ingredients deeper into the skin without irritation.

Irritation

low

Source

natural

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Stabilizer

Cyclodextrin Crosspolymer

Cyclodextrin Crosspolymer

4.0

A gentle, starch-derived powder that helps stabilize and slowly release active ingredients, making formulas more effective and less irritating.

Irritation

low

Source

semi-synthetic

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Emulsifier

Cyclodextrin Laurate

Cyclodextrin Laurate

4.0

A gentle, starch-based ingredient that helps stabilize and deliver active ingredients without irritation.

Irritation

low

Source

semi-synthetic

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