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

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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

Hair Colorant

HC Yellow No. 14

HC Yellow No. 14

3.5

HC Yellow No. 14 is a synthetic yellow dye for hair color, generally considered safe in regulated concentrations but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyhaircarecolorant
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Hair Colorant

HC Yellow No. 9

HC YELLOW NO. 9

3.5

HC Yellow No. 9 is a synthetic colorant used in hair dyes, generally considered safe for most people but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyhaircarecolorant
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Film Former

Hema Glucoside Copolymer

HEMA GLUCOSIDE/ETHYLMETHACRYLATE TRIMONIUM CHLORIDE COPOLYMER

4.0

A gentle conditioning polymer that helps hair feel soft and reduces frizz without heavy buildup.

Irritation

low

Source

synthetic

beautyskincarehaircarefilm former
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Colorant

Henna

Lawsonia Inermis Leaf Extract

3.8

Henna is a natural colorant and conditioner, but its safety depends on purity and source—avoid products with added metallic salts or synthetic dyes.

Irritation

low

Source

natural

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Colorant

Henna Extract

Lawsonia Inermis Flower/Fruit/Leaf Extract

3.8

Henna extract is a natural colorant and conditioner, but it can cause allergic reactions in sensitive individuals and may not be suitable for all hair types.

Irritation

low

Source

natural

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Film Former

Hexadimethrine Chloride

Hexadimethrine Chloride

3.5

Hexadimethrine Chloride helps hair hold its shape and reduces static, but it can be drying or irritating for sensitive scalps.

Irritation

moderate

Source

synthetic

beautyskincarehaircarefilm former
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Film Former

Hydrogen Dimethicone

Hydrogen Dimethicone

4.0

Hydrogen Dimethicone is a gentle silicone that smooths and protects skin and hair without clogging pores or causing irritation.

Irritation

low

Source

synthetic

beautyskincarehaircarefilm-former
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Emollient

Hydrogen Diphenyl Dimethicone

Hydrogen Diphenyl Dimethicone

4.0

A gentle silicone that smooths skin and hair without clogging pores, making it a reliable choice for most skin types.

Irritation

low

Source

synthetic

beautyskincarehaircare
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Emulsifier

Hydrogenated Ditallowamine

Hydrogenated Ditallowamine

3.5

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

Irritation

moderate

Source

synthetic

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Antistatic Agent

Hydrogenated Paltrimonium Chloride

Hydrogenated Paltrimonium Chloride

3.5

A conditioning ingredient that reduces static and softens hair, but may be too heavy for fine hair or acne-prone skin.

Irritation

moderate

Source

semi-synthetic

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Conditioning Agent

Hydrogenated Tallowalkonium Chloride

Hydrogenated Tallowalkonium Chloride

3.5

A conditioning ingredient derived from animal fats that softens hair and reduces static, but may cause irritation or clog pores in sensitive individuals.

Irritation

moderate

Source

semi-synthetic

beautyskincarehaircareconditioning agent
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Antistatic Agent

Hydrogenated Tallowtrimonium Chloride

Hydrogenated Tallowtrimonium Chloride

3.8

A conditioning agent derived from tallow that softens hair and reduces static, but may be too heavy for fine hair or acne-prone skin.

Irritation

moderate

Source

semi-synthetic

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Hair conditioning agent

Hydrolyzed Avocado Protein

Hydrolyzed Avocado Protein

4.0

A gentle, plant-derived protein that helps strengthen hair and lightly moisturize skin without irritation.

Irritation

low

Source

natural

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Hair Conditioning Agent

Hydrolyzed Brazil Nut Protein

Hydrolyzed Brazil Nut Protein

4.0

A gentle, plant-based protein that can temporarily strengthen hair and lightly moisturize skin without irritation.

Irritation

low

Source

natural

beautyskincarehaircareconditioning agent
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Film Former

Hydrolyzed Conchiolin Protein

Hydroxypropyltrimonium Hydrolyzed Conchiolin Protein

4.0

A gentle, protein-rich ingredient from pearl shells that helps smooth hair and temporarily plump skin by forming a light film.

Irritation

low

Source

natural

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Surfactant

Hydrolyzed Corn Protein Surfactant

SODIUM/TEA-UNDECYLENOYL HYDROLYZED CORN PROTEIN

4.0

A gentle, protein-based surfactant that cleans without stripping, making it ideal for sensitive skin and hair.

Irritation

low

Source

semi-synthetic

beautyskincarehaircarecleansing agent
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Hair Conditioning Agent

Hydrolyzed Corn Soy Wheat Protein Complex

HYDROLYZED CORN/SOY/WHEAT PROTEIN THIOGLYCOLAMIDE/THIOPROPIONAMIDE

3.8

A modified plant protein that bonds to hair to strengthen and repair damage, but its synthetic modification may not suit all preferences.

Irritation

low

Source

semi-synthetic

beautyhaircareconditioning agent
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Film Former

Hydrolyzed Egg Protein

Hydrolyzed Egg Protein

4.0

Hydrolyzed egg protein is a gentle, natural ingredient that helps strengthen hair and temporarily smooth the skin's surface, but it is not a deep moisturizer or repair agent.

Irritation

low

Source

natural

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Film Former

Hydrolyzed Gadidae Protein

Hydrolyzed Gadidae Protein

4.0

A fish-derived protein that temporarily strengthens hair and lightly hydrates skin, best for those seeking natural, protein-rich formulas.

Irritation

low

Source

natural

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Hair Conditioner

Hydrolyzed Hazelnut Protein

Hydrolyzed Hazelnut Protein

4.0

A gentle, plant-based protein that can temporarily strengthen hair and lightly moisturize skin without clogging pores.

Irritation

low

Source

natural

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Hair conditioning agent

Hydrolyzed Hemp Seed Protein

HYDROLYZED HEMP SEED PROTEIN

4.0

A gentle, plant-derived protein that can help strengthen hair and temporarily smooth the skin's surface without irritation.

Irritation

low

Source

natural

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Humectant

Hydrolyzed Honey Protein

Hydrolyzed Honey Protein

4.0

Hydrolyzed honey protein is a gentle, natural humectant that hydrates and strengthens skin and hair without clogging pores.

Irritation

low

Source

natural

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Emollient

Hydrolyzed Jojoba Esters

HYDROLYZED JOJOBA ESTERS

4.5

A lightweight, non-greasy moisturizer derived from jojoba oil that hydrates and softens skin and hair with minimal irritation risk.

Irritation

low

Source

natural

beautyskincarehaircareemollient
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Hair Conditioning Agent

Hydrolyzed Jojoba Protein

Hydroxypropyltrimonium Hydrolyzed Jojoba Protein

4.0

A gentle, plant-derived protein that helps strengthen hair and lightly moisturize skin without irritation.

Irritation

low

Source

natural

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Hair conditioning agent

Hydrolyzed Lupine Protein

Hydrolyzed Lupine Protein

4.0

Hydrolyzed lupine protein is a gentle, plant-based protein that helps strengthen hair and lightly moisturize skin without irritation.

Irritation

low

Source

natural

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Film Former

Hydrolyzed Maple Sycamore Protein

Hydrolyzed Maple Sycamore Protein

3.8

A gentle, plant-based protein that may help strengthen hair and temporarily smooth skin, but research is limited compared to more established proteins like keratin or collagen.

Irritation

low

Source

natural

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Hair Conditioner

Hydrolyzed Milk Protein Derivative

Hydroxypropyltrimonium Hydrolyzed Milk Protein

4.0

A gentle conditioning ingredient derived from milk protein that helps hair feel softer and more manageable without heavy buildup.

Irritation

low

Source

semi-synthetic

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Hair Conditioning Agent

Hydrolyzed Oat Protein (Quaternized)

HYDROXYPROPYLTRIMONIUM HYDROLYZED OAT PROTEIN

4.3

A gentle, positively charged oat protein that clings to hair and skin to reduce frizz, add softness, and improve moisture retention without heavy buildup.

Irritation

low

Source

semi-synthetic

beautyskincarehaircareconditioning agent
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Hair Conditioning Agent

Hydrolyzed Oxidized Keratin

HYDROLYZED OXIDIZED KERATIN

4.0

A gentle, protein-based ingredient that helps strengthen and repair damaged hair by filling in gaps in the hair shaft.

Irritation

low

Source

natural

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Humectant

Hydrolyzed Pea Protein

Hydrolyzed Pea Protein

4.0

A gentle, plant-based protein that helps strengthen hair and lightly moisturize skin without common allergens.

Irritation

low

Source

natural

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Hair Conditioner

Hydrolyzed Rice Bran Protein

Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein

4.0

A gentle, protein-based conditioner from rice bran that adds softness and manageability to hair and a smooth feel to skin.

Irritation

low

Source

natural

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Film Former

Hydrolyzed Rice Protein Siloxysilicate

HYDROXYPROPYLTRIMONIUM HYDROLYZED RICE PROTEIN/SILOXYSILICATE

4.0

A gentle, dual-action ingredient that deposits a protective film on hair and skin, offering conditioning and shine without heavy buildup.

Irritation

low

Source

semi-synthetic

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Humectant

Hydrolyzed Sericin

Hydrolyzed Sericin

4.0

Hydrolyzed Sericin is a gentle silk protein that helps skin and hair retain moisture and feel smooth, with a low risk of irritation.

Irritation

low

Source

natural

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Hair Conditioning Agent

Hydrolyzed Sesame Protein

Hydrolyzed Sesame Protein

4.0

A gentle, plant-based protein that strengthens hair and lightly hydrates skin without common irritation or clogging.

Irritation

low

Source

natural

beautyskincarehaircareconditioning agent
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Film Former

Hydrolyzed Silk Crosspolymer

Hydrolyzed Silk PG-Propyl Methylsilanediol Crosspolymer

4.0

A gentle film-forming ingredient derived from silk that helps smooth and protect skin and hair without heavy residue.

Irritation

low

Source

semi-synthetic

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Film Former

Hydrolyzed Silk PG-Propyl Methylsilanediol

HYDROLYZED SILK PG-PROPYL METHYLSILANEDIOL

4.0

A gentle, semi-synthetic ingredient that combines silk proteins with a silicone-like molecule to improve skin softness and hair smoothness without heavy residue.

Irritation

low

Source

semi-synthetic

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Humectant

Hydrolyzed Soy Flour

Hydrolyzed Soy Flour

4.0

A gentle, plant-derived protein that helps hydrate and strengthen skin and hair without irritation.

Irritation

low

Source

natural

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Humectant

Hydrolyzed Soy Protein

Hydrolyzed Soy Protein

4.0

Hydrolyzed Soy Protein is a gentle, plant-derived ingredient that helps hair and skin hold onto moisture and feel smoother, but it's not a deep repair agent.

Irritation

low

Source

natural

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Conditioning agent

Hydrolyzed Soy Protein & Amino Acid Complex

Hydrolyzed Soy Protein/Vegetable Amino Acids/Lysine Hydroxypropyltrimonium Chloride

4.0

A gentle conditioning ingredient that deposits a protective film on hair and skin, improving moisture and manageability without heavy buildup.

Irritation

low

Source

semi-synthetic

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Film Former

Hydrolyzed Soy Starch

Hydrolyzed Soy Starch

4.0

A gentle, plant-based ingredient that helps skin and hair feel smooth and hydrated without clogging pores.

Irritation

low

Source

natural

beautyskincarehaircarefilm-former
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Humectant

Hydrolyzed Soybean Seed

HYDROLYZED SOYBEAN SEED

4.0

A gentle, plant-derived protein that helps hydrate and strengthen skin and hair without common irritation.

Irritation

low

Source

natural

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