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 20,769
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

Texture Enhancer

Nylon-12

Nylon-12

4.0

Nylon-12 is a safe, non-irritating synthetic powder that gives makeup a silky feel and blurs imperfections without clogging pores.

Irritation

low

Source

synthetic

beautyskincarecosmetic
Read ingredient review

Optical Brightener

Nylon-12 Fluorescent Brightener 230 Salt

Nylon-12 Fluorescent Brightener 230 Salt

3.5

A synthetic optical brightener that makes products appear whiter or brighter, but with limited safety data and no proven skincare benefit.

Irritation

low

Source

synthetic

beautyskincarecolorant
Read ingredient review

Film Former

Nylon-12/6/66 Copolymer

NYLON-12/6/66 COPOLYMER

3.8

A synthetic powder that helps makeup and skincare glide on smoothly and stay put, with a low risk of irritation.

Irritation

low

Source

synthetic

beautyskincarefilm former
Read ingredient review

Film Former

Nylon-6

NYLON-6

3.5

Nylon-6 is a safe synthetic ingredient that improves the feel and wear of makeup and skincare, but it has no active skin benefits.

Irritation

low

Source

synthetic

beautyskincaretexturizer
Read ingredient review

Texture Enhancer

Nylon-611

Nylon-611

3.5

Nylon-611 is a safe, non-irritating synthetic powder that gives makeup and skincare a silky, smooth finish while absorbing excess oil.

Irritation

low

Source

synthetic

beautyskincarecosmetic
Read ingredient review

Film Former

Nylon-611/Dimethicone Copolymer

NYLON-611/DIMETHICONE COPOLYMER

4.0

A synthetic film-forming polymer that gives a silky, smooth feel and helps makeup last longer without clogging pores.

Irritation

low

Source

synthetic

beautyskincarefilm-former
Read ingredient review

Film Former

Nylon-66

NYLON-66

3.8

Nylon-66 is a safe, non-irritating synthetic powder that improves the feel and wear of makeup, but it is not biodegradable.

Irritation

low

Source

synthetic

beautyskincaretexturizer
Read ingredient review

Antioxidant

Nymphaea Ampla Flower Extract

NYMPHAEA AMPLA FLOWER EXTRACT

3.8

A gentle, antioxidant-rich flower extract that may help calm skin and fight free radical damage, but research is still emerging.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Antioxidant

Nymphaea Tetragona Callus Culture Extract

NYMPHAEA TETRAGONA CALLUS CULTURE EXTRACT

4.0

A gentle, biotech-derived antioxidant from water lily cells that may help calm skin and fight free radical damage, though research is still early.

Irritation

low

Source

biotech

beautyskincareantioxidant
Read ingredient review

Fragrance Ingredient

O-Allyloxyanisole

O-ALLYLOXYANISOLE

3.5

O-Allyloxyanisole is a synthetic fragrance ingredient with limited public safety data; it may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Hair Dye Intermediate

O-Aminophenol

O-AMINOPHENOL

2.5

O-Aminophenol is a synthetic hair dye intermediate that helps create specific colors but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyhair colorchemical intermediate
Read ingredient review

Hair colorant

O-Aminophenol Sulfate

O-AMINOPHENOL SULFATE

3.5

A synthetic hair dye ingredient that creates warm shades but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyhair coloroxidative dye
Read ingredient review

Fragrance Ingredient

O-Anisaldehyde

O-ANISALDEHYDE

3.5

O-Anisaldehyde is a synthetic fragrance compound that adds a sweet, floral scent to products but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

O-Cresyl Acetate

O-CRESYL ACETATE

3.5

O-Cresyl Acetate 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

Preservative

O-Cymen-5-Ol

O-Cymen-5-Ol

4.0

A gentle synthetic preservative that helps keep your skincare products fresh and safe without common irritation.

Irritation

low

Source

synthetic

beautyskincarepreservative
Read ingredient review

Fragrance Ingredient

o-Tolualdehyde

O-TOLUALDEHYDE

3.0

o-Tolualdehyde is a synthetic fragrance ingredient that adds a cherry-like scent but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Preservative

O-Tolyl Biguanide

O-Tolyl Biguanide

3.5

O-Tolyl Biguanide is an effective preservative but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarepreservative
Read ingredient review

Astringent

Oak Bark Extract

Quercus Robur Bark Extract

3.8

Oak bark extract is a natural astringent and antioxidant that can help tighten pores and protect skin from environmental damage, but it may be drying for some skin types.

Irritation

low

Source

natural

beautyskincareastringent
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Antioxidant

Oak Branch/Leaf Extract

Quercus Glauca Branch/Leaf Extract

3.8

A gentle, antioxidant-rich plant extract that may help protect skin from environmental stress, though human studies are limited.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Antioxidant

Oak Bud Extract

Quercus Robur Bud Extract

3.8

A gentle botanical extract with antioxidant potential, but research on its specific benefits for skin is still limited.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Astringent

Oak Gall Extract

Quercus Infectoria Fruit Extract

3.8

Oak Gall Extract is a natural astringent that may help tighten pores and control oil, but it can be drying or irritating for sensitive skin types.

Irritation

moderate

Source

natural

beautyskincareastringent
Read ingredient review

Antioxidant

Oak Root Extract

Quercus Robur Root Extract

3.8

Oak Root Extract is a gentle antioxidant-rich botanical that may help protect skin from environmental stress, but research on its specific benefits is still limited.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Soothing agent

Oak Wood Vinegar

Quercus Glauca Wood Vinegar

3.8

A gentle, natural wood distillate that may help calm and clarify skin, but research is still emerging.

Irritation

low

Source

natural

beautyskincaresoothingpurifying
Read ingredient review

Fragrance

Oakmoss Extract

Evernia Prunastri Lichen Extract

3.5

Oakmoss extract is a classic natural fragrance ingredient with a rich, earthy scent, but it is also a common allergen that can cause skin reactions in sensitive individuals.

Irritation

moderate

Source

natural

beautyskincarefragrance
Read ingredient review

Soothing agent

Oat Bran

Avena Sativa (Oat) Bran

4.5

Oat bran is a gentle, natural ingredient that soothes and moisturizes the skin, making it ideal for sensitive or irritated skin types.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Soothing agent

Oat Bran Extract

Avena Sativa (Oat) Bran Extract

4.3

Oat bran extract is a gentle, natural ingredient that helps calm irritation and support the skin barrier, making it ideal for sensitive or reactive skin.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Soothing Agent

Oat Ferment Extract

LACTOBACILLUS/AVENA SATIVA FERMENT EXTRACT FILTRATE

4.3

A gentle, probiotic-based ingredient that helps calm irritation and strengthen the skin barrier, ideal for sensitive or reactive skin.

Irritation

low

Source

biotech

beautyskincaresoothing agent
Read ingredient review

Soothing Agent

Oat Flower/Leaf/Stem Juice

Avena Sativa (Oat) Flower/Leaf/Stem Juice

4.0

A gentle, plant-based juice that helps calm irritation and hydrate the skin, ideal for sensitive or reactive skin types.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Exfoliant

Oat Hull Fiber

Avena Sativa Hull Fiber

3.8

A gentle, natural exfoliant from oat hulls that polishes skin without harsh microbeads, ideal for sensitive skin types.

Irritation

low

Source

natural

beautyskincareexfoliant
Read ingredient review

Soothing agent

Oat Kernel Extract

Avena Sativa (Oat) Kernel Extract

4.5

Oat kernel extract is a gentle, antioxidant-rich ingredient that soothes and hydrates sensitive or irritated skin without clogging pores.

Irritation

low

Source

natural

beautyskincaresoothing
Read ingredient review

Soothing Agent

Oat Kernel Flour

Avena Sativa (Oat) Kernel Flour

4.5

Oat kernel flour is a gentle, soothing ingredient ideal for sensitive or irritated skin, offering mild exfoliation and moisture retention.

Irritation

low

Source

natural

beautyskincaresoothing agentexfoliant
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Absorbent

Oat Kernel Meal

Avena Sativa (Oat) Kernel Meal

4.5

A gentle, natural exfoliant and skin soother that's especially kind to sensitive and dry skin types.

Irritation

low

Source

natural

beautyskincareexfoliantsoothing
Read ingredient review

Emollient

Oat Kernel Oil

Avena Sativa (Oat) Kernel Oil

4.3

Oat kernel oil is a gentle, non-greasy emollient that softens and soothes dry or sensitive skin without clogging pores.

Irritation

low

Source

natural

beautyskincareemollient
Read ingredient review

Humectant

Oat Kernel Protein

AVENA SATIVA KERNEL PROTEIN

4.3

Oat kernel protein is a gentle, hydrating ingredient that supports the skin barrier and soothes dryness without irritation.

Irritation

low

Source

natural

beautyskincarehumectant
Read ingredient review

Soothing Agent

Oat Leaf Extract

Avena Sativa Leaf Extract

4.0

A gentle, antioxidant-rich extract that helps calm irritated skin and supports the skin barrier.

Irritation

low

Source

natural

beautyskincaresoothing
Read ingredient review

Antioxidant

Oat Leaf/Stalk Extract

Avena Sativa Leaf/Stalk Extract

4.0

A gentle, antioxidant-rich extract from oat leaves and stalks that helps calm and protect sensitive or irritated skin.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Soothing agent

Oat Leaf/Stem Extract

Avena Sativa (Oat) Leaf/Stem Extract

4.0

A gentle, plant-based extract that helps calm irritated skin and provides antioxidant protection without clogging pores.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Soothing Agent

Oat Meal Extract

Avena Sativa (Oat) Meal Extract

4.5

Oat meal extract is a gentle, natural ingredient that calms irritation and supports the skin barrier, making it ideal for sensitive or reactive skin.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Antioxidant

Oat Meristem Cell Extract

Avena Sativa Meristem Cell Extract

4.0

Oat meristem cell extract is a gentle antioxidant-rich ingredient that may help calm skin and support a youthful appearance, though human studies are limited.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Humectant

Oat Protein Extract

Avena Sativa (Oat) Protein Extract

4.3

Oat protein extract is a gentle, moisturizing ingredient that helps soothe and protect the skin barrier, making it ideal for sensitive or dry skin types.

Irritation

low

Source

natural

beautyskincareconditioning agent
Read ingredient review

Soothing agent

Oat Seed Water

Avena Sativa (Oat) Seed Water

4.0

Oat seed water is a gentle, hydrating ingredient that helps calm sensitive or irritated skin without clogging pores.

Irritation

low

Source

natural

beautyskincaresoothing
Read ingredient review

Emollient

Oat Sprout Oil

AVENA SATIVA SPROUT OIL

4.0

A gentle, antioxidant-rich oil from oat sprouts that helps soften and protect the skin without clogging pores.

Irritation

low

Source

natural

beautyskincareemollient
Read ingredient review

Soothing Agent

Oat Straw Extract

Avena Sativa Straw Extract

4.0

Oat straw extract is a gentle, antioxidant-rich ingredient that helps calm irritated skin and protect against environmental stress.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Surfactant

Oatamide MEA

Oatamide MEA

4.0

Oatamide MEA is a mild, oat-based ingredient that helps cleansers foam gently while leaving skin and hair feeling soft and conditioned.

Irritation

low

Source

semi-synthetic

beautyskincarehaircare
Read ingredient review

Surfactant

Oatamidopropyl Betaine

Oatamidopropyl Betaine

4.3

A gentle, plant-based surfactant that cleans without stripping, ideal for sensitive or dry skin.

Irritation

low

Source

natural

beautyskincarehaircaresurfactant
Read ingredient review

Conditioning agent

Oatamidopropyl Dimethylamine

Oatamidopropyl Dimethylamine

4.2

A mild, plant-derived conditioning ingredient that smooths hair and reduces static without heavy buildup.

Irritation

low

Source

semi-synthetic

beautyskincarehaircare
Read ingredient review

Skin conditioning agent

Ocean Pout Polypeptide-1

Ocean Pout Polypeptide-1

3.8

A marine-inspired peptide that may help firm skin and reduce fine lines, but research is still limited compared to more established peptides.

Irritation

low

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Fragrance

Ocimene

OCIMENE

3.5

Ocimene is a natural fragrant terpene that adds a fresh, herbal scent to products, but it may cause skin sensitivity in some people, especially at higher concentrations.

Irritation

moderate

Source

natural

beautyskincarefragrance
Read ingredient review

Fragrance

Ocotea Quixos Leaf Oil

OCOTEA QUIXOS LEAF OIL

3.8

Ocotea Quixos Leaf Oil adds a warm, spicy scent and offers antimicrobial benefits, but its moderate irritation risk means it's best for those without sensitive skin.

Irritation

moderate

Source

natural

beautyskincarefragrance
Read ingredient review

Antioxidant

Ocotillo Stem Extract

FOUQUIERIA SPLENDENS STEM EXTRACT

3.8

A gentle plant extract that may help calm skin and fight free radicals, though research is still early.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Emollient

Octacosanyl Glycol

Octacosanyl Glycol

4.0

A gentle, waxy emollient that helps soften and smooth skin while supporting the moisture barrier.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Emollient

Octacosanyl Glycol Isostearate

Octacosanyl Glycol Isostearate

3.8

A gentle synthetic emollient that helps skin feel soft and smooth without clogging pores, making it a safe choice for most skin types.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Antistatic Agent

Octacosatrimonium Chloride

Octacosatrimonium Chloride

3.8

A gentle conditioning ingredient that helps reduce static and improve manageability in hair products, with a low risk of irritation.

Irritation

low

Source

synthetic

beautyskincarehaircare
Read ingredient review

Emollient

Octadecane

OCTADECANE

3.5

Octadecane is a safe, lightweight emollient that softens skin and improves product texture without clogging pores.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Emollient

Octadecene

OCTADECENE

3.5

A synthetic emollient that makes products feel silky and spread easily, but offers no active skincare benefits.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Film Former

Octadecene/MA Copolymer

Octadecene/MA Copolymer

4.0

A safe, synthetic film-former that helps makeup and sunscreen stay put longer without feeling heavy.

Irritation

low

Source

synthetic

beautyskincarefilm-former
Read ingredient review

Film Former

Octadecene/MA Copolymer Esters

OCTADECENE/MA COPOLYMER OCTADODECYL/BETA-SITOSTERYL ESTERS

4.0

A gentle film-forming polymer that improves product feel and wear, with very low irritation potential.

Irritation

low

Source

semi-synthetic

beautyskincarefilm-former
Read ingredient review

Skin brightening agent

Octadecenedioic Acid

Octadecenedioic Acid

4.2

A gentle, plant-derived alternative to hydroquinone that helps fade dark spots and even out skin tone without the irritation.

Irritation

low

Source

natural

beautyskincarebrightening agent
Read ingredient review

Anti-cavity agent

Octadecenyl Ammonium Fluoride

OCTADECENYL-AMMONIUM FLUORIDE

3.5

A synthetic fluoride compound used in toothpaste to strengthen enamel and prevent cavities, but not typically found in skincare.

Irritation

low

Source

synthetic

beautyoral careanti-cavity agent
Read ingredient review