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

Soothing Agent

Masterwort Leaf Extract

PEUCEDANUM OSTRUTHIUM LEAF EXTRACT

3.8

Masterwort Leaf Extract is a gentle botanical with potential soothing and antioxidant benefits, but research is limited and it's not a standout ingredient.

Irritation

low

Source

natural

beautyskincarebotanical extract
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Soothing Agent

Mastic Gum Water

Pistacia Lentiscus Gum Water

4.0

A gentle, water-based extract from mastic tree resin that may help calm irritation and provide antioxidant protection.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Fragrance

Mastic Leaf Oil

Pistacia Lentiscus Leaf Oil

3.8

A fragrant essential oil with antioxidant potential, but may irritate sensitive skin and is best used in low concentrations.

Irritation

moderate

Source

natural

beautyskincareessential oil
Read ingredient review

Emollient

Mastic Leaf Wax

Pistacia Lentiscus Leaf Wax

4.0

A gentle, plant-derived wax that adds structure and a smooth feel to balms and creams without common irritation.

Irritation

low

Source

natural

beautyskincareemollient
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Antioxidant

Mastic Thyme Extract

Thymus Mastichina Herb Extract

4.0

A gentle, plant-based antioxidant that helps protect skin from environmental stress while offering mild soothing benefits.

Irritation

low

Source

natural

beautyskincareantioxidant
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Antimicrobial

Mastic Thyme Flower Oil

THYMUS MASTICHINA FLOWER OIL

3.8

Mastic Thyme Flower Oil offers antimicrobial and antioxidant benefits but can be irritating for sensitive skin due to its essential oil nature.

Irritation

moderate

Source

natural

beautyskincareessential oil
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Antimicrobial

Mastic Thyme Oil

THYMUS MASTICHINA HERB OIL

3.8

Mastic thyme oil offers antimicrobial and antioxidant benefits but can be irritating for sensitive skin; use in low concentrations.

Irritation

moderate

Source

natural

beautyskincareessential oil
Read ingredient review

Soothing agent

Matico Leaf Extract

Piper angustifolium leaf extract

3.8

A gentle botanical extract with antioxidant and soothing potential, but human skin research is still limited.

Irritation

low

Source

natural

beautyskincarebotanical extract
Read ingredient review

Soothing agent

Matrine

MATRINE

4.0

Matrine is a plant-derived alkaloid that helps calm redness and irritation, making it a gentle option for sensitive or acne-prone skin.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Antioxidant

Matsutake Mushroom Ferment Extract

Tricholoma Matsutake Mycelium Ferment Extract

4.0

A gentle, antioxidant-rich ferment from a rare mushroom that may help calm skin and defend against environmental stress.

Irritation

low

Source

natural

beautyskincareantioxidant
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Antioxidant

Matsutake Mushroom Powder

Tricholoma Matsutake Powder

3.8

A gentle, antioxidant-rich mushroom powder that may help soothe and protect skin, though research is still emerging.

Irritation

low

Source

natural

beautyskincareantioxidant
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Emollient

Matthiola Longipetala Seed Oil

MATTHIOLA LONGIPETALA SEED OIL

4.0

A gentle, plant-based oil that helps soften and smooth skin without clogging pores, though research on its specific benefits is still limited.

Irritation

low

Source

natural

beautyskincareemollient
Read ingredient review

Emollient

Mauloutchia Seed Butter

Mauloutchia Humblotii Seed Butter

4.0

A nourishing, plant-based butter from Madagascar that softens and conditions skin, but may be too rich for oily or acne-prone skin.

Irritation

low

Source

natural

beautyskincareemollient
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Soothing agent

Mayamaea Permit Extract

MAYAMAEA PERMITIS EXTRACT

3.8

A gentle microalgae extract that may help calm skin and fight oxidative stress, but research is still early.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Preservative

MDM Hydantoin

MDM Hydantoin

3.5

MDM Hydantoin is an effective preservative but may irritate sensitive skin due to its slow release of formaldehyde.

Irritation

moderate

Source

synthetic

beautyskincarepreservative
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Preservative

MEA O-Phenylphenate

MEA O-PHENYLPHENATE

3.5

A synthetic preservative that helps keep products fresh but may cause irritation in sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarepreservative
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Surfactant

MEA PPG-6 Laureth-7 Carboxylate

MEA PPG-6 LAURETH-7 CARBOXYLATE

4.0

A gentle synthetic surfactant that helps cleanse and emulsify without stripping the skin's natural moisture barrier.

Irritation

low

Source

synthetic

beautyskincaresurfactant
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Preservative Booster

MEA-Benzoate

MEA-Benzoate

3.5

MEA-Benzoate is a synthetic preservative helper that extends shelf life but may cause irritation for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarepreservative
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Conditioning Agent

MEA-Biotinate

MEA-Biotinate

3.5

MEA-Biotinate is a gentle, water-soluble form of biotin that may help strengthen hair and improve skin barrier function, but research is limited.

Irritation

low

Source

semi-synthetic

beautyskincarehaircare
Read ingredient review

Buffering Agent

MEA-Borate

MEA-BORATE

3.5

MEA-Borate is a mild pH adjuster that helps keep your skincare products stable and gentle, but it is not a star active ingredient.

Irritation

low

Source

synthetic

beautyskincarepH adjuster
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Surfactant

MEA-Cocoate

MEA-COCOATE

4.0

A gentle coconut-derived surfactant that helps create a rich lather while being less harsh than traditional sulfates.

Irritation

low

Source

semi-synthetic

beautyskincarecleanser
Read ingredient review

Emulsifier

MEA-Dicetearyl Phosphate

MEA-Dicetearyl Phosphate

4.0

A gentle emulsifier that helps create smooth, stable creams and lotions without common irritation.

Irritation

low

Source

semi-synthetic

beautyskincareemulsifier
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Film Former

MEA-Hydrolyzed Collagen

MEA-Hydrolyzed Collagen

3.8

A modified collagen that helps hair and skin feel smoother and more hydrated, but its large molecule size limits deep penetration.

Irritation

low

Source

semi-synthetic

beautyskincarehaircarefilm former
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Film Former

MEA-Hydrolyzed Silk

MEA-Hydrolyzed Silk

3.8

A silk protein derivative that helps hair and skin feel smooth and hydrated, but evidence is mostly anecdotal.

Irritation

low

Source

semi-synthetic

beautyskincarehaircare
Read ingredient review

Chelating Agent

MEA-Hydroxyoctyloxypyridinone

MEA-HYDROXYOCTYLOXYPYRIDINONE

4.0

A gentle chelating agent that helps your skincare products stay effective longer by neutralizing troublesome metal ions.

Irritation

low

Source

synthetic

beautyskincarechelating agent
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Surfactant

MEA-Laureth Sulfate

MEA-Laureth Sulfate

3.8

A milder alternative to SLS that still provides good foam, but may still be drying for very sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarecleanser
Read ingredient review

Surfactant

MEA-Laureth-6 Carboxylate

MEA-Laureth-6 Carboxylate

4.0

A gentle, sulfate-free surfactant that cleanses without stripping the skin, making it a good choice for sensitive or dry skin types.

Irritation

low

Source

synthetic

beautyskincarecleanser
Read ingredient review

Surfactant

MEA-Lauryl Sulfate

MEA-LAURYL SULFATE

3.8

A mild sulfate-based cleanser that effectively removes dirt and oil but may still be drying for sensitive or dry skin types.

Irritation

moderate

Source

synthetic

beautyskincarecleanser
Read ingredient review

Surfactant

MEA-PPG-8 Steareth-7 Carboxylate

MEA-PPG-8-STEARETH-7 CARBOXYLATE

4.0

A gentle synthetic surfactant that cleanses without stripping the skin, often used in sulfate-free and sensitive-skin formulas.

Irritation

low

Source

synthetic

beautyskincarecleansing
Read ingredient review

Reducing Agent

MEA-Sulfite

MEA-Sulfite

3.5

MEA-Sulfite is a synthetic reducing agent used in hair treatments and some skincare, but it may cause irritation for sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincarehaircare
Read ingredient review

Surfactant

MEA-Undecylenate

MEA-Undecylenate

3.8

A mild cleansing agent with antimicrobial properties, best for rinse-off products and acne-prone skin.

Irritation

moderate

Source

semi-synthetic

beautyskincarecleansing agent
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Antioxidant

Meadow Rue Flower Extract

Thalictrum Occidentale Flower Extract

3.5

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

Irritation

low

Source

natural

beautyskincarebotanical extract
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Exfoliant

Meadowfoam Delta-Lactone

Meadowfoam Delta-Lactone

4.3

A mild, plant-based exfoliant derived from meadowfoam seed oil that gently resurfaces skin without the sting of stronger acids.

Irritation

low

Source

natural

beautyskincareexfoliant
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Emollient

Meadowfoam Estolide

Meadowfoam Estolide

4.5

A silky, non-greasy emollient from meadowfoam seeds that hydrates and softens skin without clogging pores.

Irritation

low

Source

natural

beautyskincareemollient
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Emollient

Meadowfoam Seed Oil

Limnanthes Alba Seed Oil

4.5

A non-greasy, stable plant oil that hydrates and softens skin without clogging pores.

Irritation

low

Source

natural

beautyskincareemollient
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Surfactant

Meadowfoamamidopropyl Betaine

Meadowfoamamidopropyl Betaine

4.5

A gentle, plant-based surfactant that cleanses without stripping the skin, making it ideal for sensitive and dry skin types.

Irritation

low

Source

natural

beautyskincarecleanser
Read ingredient review

Soothing Agent

Meadowsweet Flower Extract

Spiraea Ulmaria Flower Extract

4.0

A gentle botanical extract with soothing and antioxidant benefits, ideal for sensitive or irritated skin.

Irritation

low

Source

natural

beautyskincarebotanical extract
Read ingredient review

Soothing Agent

Meadowsweet Flower Water

Spiraea Ulmaria Flower Water

3.8

A mild botanical water that can help calm and refresh skin, but its astringent properties may be too drying for very sensitive or dry skin types.

Irritation

low

Source

natural

beautyskincarebotanical
Read ingredient review

Soothing agent

Meadowsweet Root Extract

Spiraea Ulmaria Root Extract

3.8

A gentle botanical extract from meadowsweet root that may help calm skin and tighten pores, but research is limited compared to more studied soothing ingredients.

Irritation

low

Source

natural

beautyskincarebotanical
Read ingredient review

Humectant

Mealworm Larva Extract

TENEBRIO MOLITOR LARVA EXTRACT

3.5

Mealworm larva extract is an emerging, sustainable ingredient with potential moisturizing and antioxidant benefits, but research in human skincare is very limited.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Antioxidant

Meconopsis Horridula Flower Extract

MECONOPSIS HORRIDULA FLOWER EXTRACT

3.8

A gentle, antioxidant-rich plant extract from the Himalayas that may help calm and protect skin, though research is still early.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Antioxidant

Medlar Fruit Extract

Pyrus Germanica Extract

3.8

A gentle, antioxidant-rich fruit extract that may help protect skin from environmental stress, though research is still emerging.

Irritation

low

Source

natural

beautyskincareantioxidant
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Other

MEL

MEL

2.5

MEL is an ambiguous label that likely refers to a melanin derivative or a typo; its benefits and safety are not well-documented.

Irritation

low

Source

mixed

beautyskincareother
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Antimicrobial

Melaleuca Bracteata Leaf Extract

MELALEUCA BRACTEATA LEAF EXTRACT

3.8

A botanical extract with antimicrobial potential, but limited human studies and a risk of skin irritation at higher concentrations.

Irritation

moderate

Source

natural

beautyskincarebotanical extract
Read ingredient review

Fragrance

Melaleuca Ericifolia Leaf Oil

MELALEUCA ERICIFOLIA LEAF OIL

3.8

A fragrant essential oil with mild antimicrobial potential, best used in low concentrations to avoid skin irritation.

Irritation

moderate

Source

natural

beautyskincareessential oil
Read ingredient review

Antioxidant

Melaleuca Flower-Leaf Extract

Melaleuca symphyocarpa flower/leaf extract

3.8

A gentle botanical extract with antioxidant potential, but research is limited compared to more common Melaleuca species.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Antioxidant

Melaleuca Glomerata Extract

Melaleuca Glomerata Leaf/Stem Extract

3.8

A gentle botanical extract with antioxidant potential, but research is limited compared to more studied plant extracts.

Irritation

low

Source

natural

beautyskincareantioxidant
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Antimicrobial

Melaleuca Teretifolia Oil

MELALEUCA TERETIFOLIA BRANCH/LEAF OIL

3.8

A botanical essential oil with antimicrobial potential, but limited research and a risk of skin irritation for sensitive individuals.

Irritation

moderate

Source

natural

beautyskincareessential oil
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Antioxidant

Melaleuca Uncinata Extract

Melaleuca Uncinata Flower/Leaf 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

Antioxidant

Melanin

Melanin

3.8

Melanin is a promising antioxidant and UV-protective ingredient, but its use in cosmetics is still emerging and not yet widely proven in human studies.

Irritation

low

Source

natural

beautyskincareantioxidant
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Antioxidant

Melastoma Candidum Extract

MELASTOMA CANDIDUM EXTRACT

3.8

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

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review