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

Emollient

Propanediol Dicaprylate

Propanediol Dicaprylate

4.3

A gentle, lightweight emollient that hydrates and softens skin without clogging pores, ideal for oily and sensitive skin types.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Emollient

Propanediol Dicaprylate/Caprate

PROPANEDIOL DICAPRYLATE/CAPRATE

4.2

A lightweight, non-greasy emollient that softens skin without clogging pores, ideal for oilier or acne-prone skin types.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Emollient

Propanediol Dipelargonate

Propanediol Dipelargonate

4.0

A lightweight, non-greasy emollient that softens skin without clogging pores, ideal for sensitive and oily skin types.

Irritation

low

Source

synthetic

beautyskincareemollient
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Film Former

Propanediol Rosinates

Propanediol Rosinates

3.5

A pine-derived film former that helps makeup last longer and resist water, but may feel tacky or heavy on some skin types.

Irritation

low

Source

semi-synthetic

beautyskincarefilm-former
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Emulsifier

Propanediol Stearate

Propanediol Stearate

4.0

A gentle emulsifier that helps water and oil mix, making creams feel smooth without common irritation.

Irritation

low

Source

semi-synthetic

beautyskincareemulsifier
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Emollient

Propanediyl 3-Hydroxycaprate

Propanediyl 3-Hydroxycaprate

4.0

A gentle synthetic emollient that hydrates and smooths skin without clogging pores, ideal for sensitive and oily skin types.

Irritation

low

Source

synthetic

beautyskincareemollient
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Fragrance Ingredient

Propenyl p-Cymene

PROPENYL P-CYMENE

3.5

Propenyl p-Cymene is a synthetic fragrance ingredient that adds scent to products but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
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Preservative

Propionic Acid

Propionic Acid

3.5

Propionic acid is an effective preservative but can be irritating at higher concentrations, so it's best for well-formulated products.

Irritation

moderate

Source

synthetic

beautyskincarepreservative
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Antioxidant

Propolis Ferment Extract

Saccharomyces/Propolis Ferment Extract

4.0

A fermented propolis extract that may help soothe and protect the skin, though research is still emerging.

Irritation

low

Source

biotech

beautyskincareantioxidant
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Soothing Agent

Propolis Wax

Propolis Cera

4.0

A bee-derived ingredient that helps calm irritation and provides antioxidant protection, but may not suit those with bee product allergies.

Irritation

low

Source

natural

beautyskincaresoothing agent
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Humectant

Propoxypropanediol

PROPOXYPROPANEDIOL

4.0

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

Irritation

low

Source

synthetic

beautyskincarehumectant
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Solvent

Propyl Acetate

Propyl Acetate

3.5

Propyl Acetate helps products spread and dry quickly, but it can be drying or irritating for sensitive skin, especially around nails.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
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Solvent

Propyl Alcohol

PROPYL ALCOHOL

3.0

Propyl alcohol is a solvent that helps ingredients mix and can kill bacteria, but it may strip moisture and irritate sensitive or dry skin.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
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Fragrance Ingredient

Propyl Benzoate

Propyl Benzoate

3.5

Propyl benzoate is a synthetic fragrance ingredient that helps scent and stabilize products, but it offers no direct skin benefit and may be a concern for those avoiding synthetic fragrances.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Fragrance Ingredient

Propyl Butyrate

Propyl Butyrate

3.8

Propyl Butyrate is a synthetic ester used mainly for its light, fruity scent; it is generally considered safe at low levels but offers no direct skin benefit.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Antioxidant

Propyl Gallate

Propyl Gallate

3.8

Propyl Gallate is a reliable preservative booster that helps keep your products fresh, but it's best for those without sensitive skin.

Irritation

low

Source

synthetic

beautyskincareantioxidant
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Film Former

Propyl Methacrylate

Propyl Methacrylate

3.8

A synthetic film-former that helps nail polish last longer, but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarenail care
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Emollient

Propyl Octanoate

Propyl Octanoate

4.0

A lightweight, non-greasy emollient that helps soften skin without clogging pores.

Irritation

low

Source

synthetic

beautyskincareemollient
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Antioxidant

Propyl Oleoyl Grape Seed Extract

PROPYL OLEOYL GRAPE SEED EXTRACT

3.8

A semi-synthetic antioxidant that combines grape seed benefits with better oil compatibility, but research is still limited.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
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Fragrance Ingredient

Propyl Phenylacetate

PROPYL PHENYLACETATE

3.5

Propyl Phenylacetate is a synthetic fragrance ingredient that adds a sweet, honey-like scent to products; it is generally considered safe at low concentrations but offers no skincare benefits.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Solvent

Propyl Propionate

Propyl Propionate

3.5

A mild synthetic solvent and fragrance ingredient that is generally safe at low concentrations but offers no direct skin benefit.

Irritation

low

Source

synthetic

beautyskincaresolvent
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Antistatic Agent

Propyl Steardimonium Chloride

Propyl Steardimonium Chloride

3.5

An effective hair conditioner and antistatic agent, but may cause irritation or clog pores in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarehaircare
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Skin conditioner

Propyl Trimethicone

Propyl Trimethicone

4.0

A gentle silicone that makes products feel silky and helps them glide on without clogging pores.

Irritation

low

Source

synthetic

beautyskincaresilicone
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Emollient

Propyl Trisiloxane

Propyl Trisiloxane

4.0

A lightweight silicone that gives a smooth, silky feel without clogging pores or causing irritation.

Irritation

low

Source

synthetic

beautyskincarehaircare
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Emollient

Propyl Valerate

Propyl Valerate

4.0

A lightweight, non-greasy emollient that softens skin and improves product texture with low irritation potential.

Irritation

low

Source

synthetic

beautyskincareemollient
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Solvent

Propylene Carbonate

Propylene Carbonate

3.5

Propylene carbonate is an effective solvent but can be irritating for sensitive skin; it's best reserved for rinse-off or low-concentration formulas.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
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Humectant

Propylene Glycol

Propylene Glycol

3.8

Propylene glycol is a widely used, effective humectant and solvent, but it can be irritating for sensitive skin at high concentrations.

Irritation

moderate

Source

synthetic

beautyskincarehumectant
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Thickener

Propylene Glycol Alginate

Propylene Glycol Alginate

4.0

A gentle, seaweed-based thickener that improves product feel and stability without common irritation concerns.

Irritation

low

Source

semi-synthetic

beautyskincarethickener
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Solvent

Propylene Glycol Butyl Ether

PROPYLENE GLYCOL BUTYL ETHER

3.5

A functional solvent that helps products spread and mix, but may cause irritation for sensitive skin at higher concentrations.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
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Emulsifier

Propylene Glycol Capreth-4

PROPYLENE GLYCOL CAPRETH-4

4.0

A gentle emulsifier that helps mix water and oil in skincare products, with a low risk of irritation or clogged pores.

Irritation

low

Source

semi-synthetic

beautyskincareemulsifier
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Emollient

Propylene Glycol Caprylate

Propylene Glycol Caprylate

4.0

A gentle, lightweight emollient that helps soften skin and improve product texture without clogging pores.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Humectant

Propylene Glycol Citrate

Propylene Glycol Citrate

4.0

A gentle, water-attracting ingredient that helps keep skin hydrated and balanced without common irritations.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
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Plasticizer

Propylene Glycol Dibenzoate

Propylene Glycol Dibenzoate

3.5

A synthetic ester that improves product texture and flexibility, especially in nail and lip formulas, with a low irritation profile.

Irritation

low

Source

synthetic

beautyskincarenail care
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Emollient

Propylene Glycol Dicaprylate

Propylene Glycol Dicaprylate

4.0

A lightweight, synthetic emollient that helps products spread smoothly without clogging pores or feeling heavy.

Irritation

low

Source

synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Dicocoate

PROPYLENE GLYCOL DICOCOATE

4.0

A gentle, coconut-derived emollient that helps soften skin without clogging pores, making it a good choice for sensitive and acne-prone skin types.

Irritation

low

Source

synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Diethylhexanoate

Propylene Glycol Diethylhexanoate

4.0

A lightweight synthetic emollient that spreads easily and leaves a silky finish, generally well-tolerated by most skin types.

Irritation

low

Source

synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Dilaurate

Propylene Glycol Dilaurate

3.5

A synthetic emollient that softens skin and improves product feel, but may be moderately pore-clogging for some.

Irritation

low

Source

synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Dipelargonate

Propylene Glycol Dipelargonate

4.0

A lightweight, synthetic emollient that softens skin without clogging pores, commonly used to improve product texture.

Irritation

low

Source

synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Distearate

Propylene Glycol Distearate

4.0

A gentle synthetic emollient that helps create a smooth, creamy texture in skincare products without clogging pores.

Irritation

low

Source

synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Hydroxystearate

Propylene Glycol Hydroxystearate

4.0

A gentle emollient and emulsifier that helps products feel smooth and spread easily, with a low risk of irritation or clogged pores.

Irritation

low

Source

synthetic

beautyskincareemollient
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Emulsifier

Propylene Glycol Isodeceth-12

Propylene Glycol Isodeceth-12

3.8

A gentle synthetic emulsifier that helps water and oil mix in your skincare products, generally well-tolerated by most skin types.

Irritation

low

Source

synthetic

beautyskincareemulsifier
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