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 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
Read ingredient review

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
Read ingredient review

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
Read ingredient review

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
Read ingredient review

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
Read ingredient review

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
Read ingredient review

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
Read ingredient review

Emulsifier

Propylene Glycol Isodeceth-4

PROPYLENE GLYCOL ISODECETH-4

3.8

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

Irritation

low

Source

synthetic

beautyskincaresurfactant
Read ingredient review

Emollient

Propylene Glycol Isostearate

Propylene Glycol Isostearate

3.8

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

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Laurate

Propylene Glycol Laurate

4.0

A gentle, synthetic emollient that helps soften skin and stabilize formulas without common irritation.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Emulsifier

Propylene Glycol Laureth-6

PROPYLENE GLYCOL LAURETH-6

3.8

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

Irritation

low

Source

synthetic

beautyskincaresurfactant
Read ingredient review

Emollient

Propylene Glycol Linoleate

Propylene Glycol Linoleate

3.8

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

Irritation

low

Source

semi-synthetic

beautyskincareemollient
Read ingredient review

Emollient

Propylene Glycol Linolenate

PROPYLENE GLYCOL LINOLENATE

3.8

A gentle emollient that helps soften and smooth skin by replenishing essential fatty acids, with a low risk of irritation.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Oleate

Propylene Glycol Oleate

3.8

A mild emollient and emulsifier that helps soften skin and blend ingredients, but may be slightly pore-clogging for acne-prone skin.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
Read ingredient review

Emulsifier

Propylene Glycol Oleate SE

Propylene Glycol Oleate SE

3.5

A reliable emulsifier that helps blend oil and water in creams, but it's not a star active ingredient for skin benefits.

Irritation

low

Source

semi-synthetic

beautyskincareemollientemulsifier
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Emulsifier

Propylene Glycol Oleth-5

PROPYLENE GLYCOL OLETH-5

3.8

A synthetic emulsifier that helps mix oil and water in products, but may cause mild irritation for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincareemulsifier
Read ingredient review

Emollient

Propylene Glycol Ricinoleate

Propylene Glycol Ricinoleate

3.8

A gentle emollient that helps soften skin and improve product texture, with a low risk of irritation or clogged pores.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Emollient

Propylene Glycol Soyate

PROPYLENE GLYCOL SOYATE

3.8

A gentle, plant-based emollient that helps soften and smooth skin without heavy greasiness.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Emulsifier

Propylene Glycol Stearate

Propylene Glycol Stearate

3.8

A reliable emulsifier that helps create smooth, stable creams and lotions with a low risk of irritation.

Irritation

low

Source

semi-synthetic

beautyskincareemulsifier
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Emulsifier

Propylene Glycol Stearate SE

Propylene Glycol Stearate SE

4.0

A reliable emulsifier that helps water and oil mix into a stable, creamy texture without common irritation concerns.

Irritation

low

Source

semi-synthetic

beautyskincareemulsifier
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Emollient

Propylheptyl Caprylate

Propylheptyl Caprylate

4.0

A silky, lightweight emollient that helps products spread smoothly without feeling heavy or greasy.

Irritation

low

Source

synthetic

beautyskincareemollient
Read ingredient review

Fragrance Ingredient

Propylidene Phthalide

PROPYLIDENE PHTHALIDE

3.8

A natural fragrance compound from celery seed that adds a warm, spicy scent but offers no direct skincare benefits.

Irritation

low

Source

natural

beautyskincarefragrance
Read ingredient review

Preservative

Propylparaben

Propylparaben

3.5

Propylparaben is an effective preservative but has raised safety concerns due to potential endocrine-disrupting effects, leading many brands to phase it out.

Irritation

low

Source

synthetic

beautyskincarepreservative
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