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

Emollient

Tetradecyloctadecanol

TETRADECYLOCTADECANOL

4.0

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

Irritation

low

Source

synthetic

beautyskincareemollient
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Emollient

Tetradecylpropionates

TETRADECYLPROPIONATES

4.0

Tetradecylpropionates are gentle emollients that help soften skin without feeling greasy, making them a good choice for lightweight moisturizers.

Irritation

low

Source

synthetic

beautyskincareemollient
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Antioxidant

Tetradesmus Obliquus Extract

Tetradesmus Obliquus Extract

4.0

A gentle algae extract that helps hydrate and protect skin from environmental stress, though research is still developing.

Irritation

low

Source

natural

beautyskincareantioxidant
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Antioxidant

Tetrahexyldecyl Ascorbate

Tetrahexyldecyl Ascorbate

4.5

A gentle, stable vitamin C that penetrates skin well and brightens without the sting of L-ascorbic acid.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
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Fragrance

Tetrahydro Linalool

TETRAHYDROLINALOOL

3.5

A synthetic scent ingredient that adds a pleasant floral-woody note but offers no skincare benefit and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Emollient

Tetrahydro Mugyl Acetate

TETRAHYDROMUGYL ACETATE

3.8

A gentle synthetic emollient that helps soften and smooth skin with a lightweight feel, but research on its long-term effects is limited.

Irritation

low

Source

synthetic

beautyskincareemollient
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Fragrance Ingredient

Tetrahydro Pentylfurfuryl Acetate

TETRAHYDRO-PENTYLFURFURYL ACETATE

3.5

A synthetic fragrance ingredient that adds a pleasant scent but offers no skincare benefits and may be a concern for those with fragrance sensitivities.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Tetrahydro Trimethyl Vinyl Pyran

TETRAHYDRO-TRIMETHYL-VINYL-PYRAN

3.5

A synthetic scent ingredient that adds a fresh, woody note to products but offers no skin benefit and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Tetrahydro-2-isobutyl-4-methyl-2H-pyran

TETRAHYDRO-2-ISOBUTYL-4-METHYL-2H-PYRAN

3.5

A synthetic scent ingredient that adds a fresh note to products; generally safe at low levels but may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

Tetrahydro-Naphthalene Ethanol

TETRAHYDRONAPHTHALENE-2-ETHANOL

3.5

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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Fragrance Ingredient

Tetrahydro-p-cresyloxypyran

TETRAHYDRO-P-CRESYLOXYPYRAN

3.5

A synthetic fragrance ingredient that adds a sweet floral note to products; generally safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

Tetrahydrocitronellols Blend

7-METHYL-3-METHYLENE-1,6-OCTADIENE TETRAHYDROCITRONELLOLS

3.5

A synthetic fragrance ingredient that adds a pleasant scent but offers no skincare benefits and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Antioxidant

Tetrahydrocurcumin Diacetate

TETRAHYDROCURCUMIN DIACETATE

4.0

A gentle, stabilized turmeric derivative that helps even skin tone and fights oxidative stress without the yellow staining of raw curcumin.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
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Antioxidant

Tetrahydrodemethylcurcumin

Tetrahydrodemethylcurcumin

4.0

A stable, non-staining turmeric derivative that fights oxidative stress and helps even skin tone without the yellow tint of raw turmeric.

Irritation

low

Source

natural

beautyskincareantioxidant
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Antioxidant

Tetrahydrodiferuloylmethane

Tetrahydrodiferuloylmethane

4.0

A gentle, stable antioxidant derived from turmeric that helps protect skin from environmental stress without the staining or irritation of raw curcumin.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
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Fragrance Ingredient

Tetrahydrodimethylbenzofuranone

TETRAHYDRO-DIMETHYL-BENZOFURAN-2-ONE

3.5

A synthetic scent ingredient that adds a sweet, warm note to products; generally considered safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Tetrahydrodimethylnaphthyl Propanone

TETRAHYDRO-DIMETHYLNAPHTHYL-PROPAN-1-ONE

3.5

A synthetic scent ingredient that adds a warm, woody note to products but offers no skincare benefit and may be unnecessary for sensitive noses.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Solvent

Tetrahydrofurfuryl Acetate

TETRAHYDROFURFURYL ACETATE

3.5

A synthetic solvent and fragrance ingredient that helps dissolve other ingredients but may cause irritation for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
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Solvent

Tetrahydrofurfuryl Alcohol

TETRAHYDROFURFURYL ALCOHOL

3.5

A synthetic solvent that helps other ingredients absorb deeper into skin, but may cause irritation for sensitive types.

Irritation

moderate

Source

synthetic

beautyskincaresolvent
Read ingredient review

Emollient

Tetrahydrofurfuryl Ricinoleate

Tetrahydrofurfuryl Ricinoleate

3.8

A gentle, non-greasy emollient that softens skin and improves product texture, with a low risk of irritation or clogged pores.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
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Fragrance

Tetrahydrogeranial

TETRAHYDROGERANIAL

3.5

A synthetic citrus-scented fragrance ingredient that can cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Tetrahydroindeno-Dioxin

TETRAHYDROINDENO-DIOXIN

3.5

Tetrahydroindeno-Dioxin is a synthetic fragrance ingredient with limited research; it is generally considered safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

Tetrahydroionone

TETRAHYDRONAPHTHALENE-1-ACETALDEHYDE

3.5

A synthetic scent ingredient that adds a woody-floral note but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Emollient

Tetrahydroisoocimenol

TETRAHYDROISOOCIMENOL

4.0

A lightweight synthetic emollient that hydrates without clogging pores, ideal for oily and acne-prone skin.

Irritation

low

Source

synthetic

beautyskincareemollient
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Sebum Regulator

Tetrahydrojasmonic Acid

TETRAHYDROJASMONIC ACID

4.0

A gentle, plant-inspired ingredient that helps balance oil production and refine pores without drying out the skin.

Irritation

low

Source

synthetic

beautyskincaresebum regulator
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Antioxidant

Tetrahydromagnolol

Tetrahydromagnolol

4.0

A gentle antioxidant derived from magnolia bark that helps calm skin and fight free radical damage without common irritation.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
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Fragrance Ingredient

Tetrahydromyrcenyl Acetate

TETRAHYDROMYRCENYL ACETATE

4.0

A synthetic scent ingredient that adds a fresh, citrusy note to products but offers no direct skin benefit.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Tetrahydronaphthalenol

TETRAHYDRONAPHTHALENOL

3.5

Tetrahydronaphthalenol 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

Soothing Agent

Tetrahydropalmatine HCl

TETRAHYDROPALMATINE HCL

3.5

Tetrahydropalmatine HCl is a plant alkaloid that may help calm skin, but research in cosmetics is still emerging.

Irritation

low

Source

natural

beautyskincaresoothing agent
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Penetration Enhancer

Tetrahydropiperine

TETRAHYDROPIPERINE

3.8

Tetrahydropiperine boosts the absorption of other skincare ingredients but may cause tingling or irritation in sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarepenetration enhancer
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Antioxidant

Tetrahydropyranyloxy Phenol

TETRAHYDROPYRANYLOXY PHENOL

3.5

A synthetic antioxidant that may help protect skin from environmental stress, but research is still limited.

Irritation

low

Source

synthetic

beautyskincareantioxidant
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Antioxidant

Tetrahydroxy Chalcone

Tetraacetoxychalcone

3.8

A synthetic antioxidant that may help calm skin and fight free radicals, but research is still early.

Irritation

low

Source

synthetic

beautyskincareantioxidant
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Antioxidant

Tetrahydroxybutyl Timonacic

Tetrahydroxybutyl Timonacic

3.8

A synthetic antioxidant that may help protect skin from environmental stress, but research is still emerging.

Irritation

low

Source

synthetic

beautyskincareantioxidant
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Chelating Agent

Tetrahydroxyethyl Ethylenediamine

TETRAHYDROXYETHYL ETHYLENEDIAMINE

4.0

A gentle chelating agent that helps your skincare products stay effective and stable by neutralizing hard water minerals.

Irritation

low

Source

synthetic

beautyskincarestabilizer
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Fragrance

Tetralol

TETRAHYDRONAPHTHALENE-1-ETHANOL

3.0

A synthetic fragrance ingredient with limited safety data; best for those who tolerate synthetic scents well.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Tetramethyl Acetyloctahydronaphthalenes

TETRAMETHYL ACETYLOCTAHYDRONAPHTHALENES

3.5

A widely used synthetic fragrance that gives a warm, woody scent but offers no skincare benefits and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Fragrance Ingredient

Tetramethyl Cyclohexene Methyl Formate

TETRAMETHYL-3-CYCLOHEXENE-1-METHYL FORMATE

3.5

A synthetic scent ingredient that adds a fresh floral note but offers no skincare benefit and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Antioxidant

Tetramethyl Cyclopentene Butenol

TETRAMETHYL CYCLOPENTENE BUTENOL

4.0

A lab-made antioxidant that helps defend skin against pollution and UV-related damage, often found in anti-aging formulas.

Irritation

low

Source

synthetic

beautyskincareantioxidant
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Fragrance Ingredient

Tetramethyl Cyclopentenebutanol

TETRAMETHYL-3-CYCLOPENTENEBUTANOL

3.5

A synthetic scent ingredient that adds a pleasant floral-woody note but offers no skincare benefits and may trigger sensitivities in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Tetramethyl Decadienenitrile

TETRAMETHYL-4,8-DECADIENENITRILE

3.5

A synthetic scent ingredient that adds a fresh citrus note but offers no skincare benefits and may be a concern for those avoiding fragrance.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Fragrance Ingredient

Tetramethyl Methyleneheptanone

TETRAMETHYL-4-METHYLENEHEPTAN-2-ONE

3.5

A synthetic fragrance ingredient that adds a fresh scent but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
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Fragrance Ingredient

Tetramethyl Oxaspirodecene

TETRAMETHYL-1-OXASPIRO-6-DECENE

3.5

A synthetic scent ingredient that adds a pleasant note to products but offers no skincare benefit and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
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Anti-Wrinkle Agent

Tetramethyl Pyrazolylpyrimidine HCl

TETRAMETHYL PYRAZOLYLPYRIMIDINE HCL

3.8

A synthetic compound that may help soften expression lines by relaxing facial muscles, but research is still limited compared to more established ingredients.

Irritation

low

Source

synthetic

beautyskincareactive
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Fragrance Ingredient

Tetramethyl-4-Methylene-2-Heptanol

TETRAMETHYL-4-METHYLENE-2-HEPTANOL

3.5

A synthetic scent ingredient that adds a fresh note but offers no skincare benefit and may cause sensitivity in some people.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review