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

Skin conditioning agent

Lysophosphatidic Acid

LYSOPHOSPHATIDIC ACID

3.8

A gentle lipid that may help strengthen the skin barrier and improve hydration, but research is still early.

Irritation

low

Source

natural

beautyskincarelipid
Read ingredient review

Delivery agent

Lysophosphatidylcholynyl Chlorin E6

LYSOPHOSPHATIDYLCHOLINYLCHLORIN E6

3.0

An experimental ingredient with potential for light-activated delivery, but very limited safety and efficacy data in everyday skincare.

Irritation

moderate

Source

semi-synthetic

beautyskincareactive
Read ingredient review

Skin conditioning agent

Lysophosphatidylglycerol

Lysophosphatidylglycerol

4.2

A mild, lipid-based ingredient that supports the skin barrier and helps keep moisture in without clogging pores.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
Read ingredient review

Antimicrobial

Lysozyme

Lysozyme

3.8

Lysozyme is a gentle enzyme that helps control unwanted bacteria on the skin, making it a mild alternative to harsher antimicrobial ingredients.

Irritation

low

Source

natural

beautyskincareenzyme
Read ingredient review

Soothing Agent

Lysyl Ornithine

Lysyl Ornithine

3.8

Lysyl Ornithine is a gentle, amino-acid-based ingredient that may help calm irritated skin, but research is still early.

Irritation

low

Source

semi-synthetic

beautyskincaresoothing agent
Read ingredient review

Hair Dye Intermediate

M-Aminophenol

M-AMINOPHENOL

3.0

M-Aminophenol is a synthetic dye ingredient used in hair color to achieve cool, ashy tones, but it can be a skin irritant and allergen for some people.

Irritation

moderate

Source

synthetic

beautyhair colordye intermediate
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Hair colorant

M-Aminophenol HCl

M-AMINOPHENOL HCL

2.5

M-Aminophenol HCl is a synthetic dye ingredient used in permanent hair color to create cool, ashy shades, but it can be a skin irritant for some people.

Irritation

moderate

Source

synthetic

beautyhair colorcolorant
Read ingredient review

Hair Dye Intermediate

M-Aminophenol Sulfate

M-AMINOPHENOL SULFATE

3.5

A synthetic hair dye intermediate that helps create cool, ash tones in permanent color, but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyhair-colorsynthetic
Read ingredient review

Fragrance Ingredient

M-Cresyl Acetate

M-CRESYL ACETATE

3.5

M-Cresyl Acetate is a synthetic fragrance ingredient that adds a sweet, floral note to products, but may cause irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Film Former

M-Dimethylaminophenyl Urea

M-DIMETHYLAMINOPHENYL UREA

3.0

A synthetic film-former that helps products spread evenly and feel smooth, but with limited published safety data.

Irritation

low

Source

synthetic

beautyskincarefilm-former
Read ingredient review

Fragrance Ingredient

M-Hydroxyanisole

M-HYDROXYANISOLE

3.5

M-Hydroxyanisole is a synthetic fragrance and antioxidant ingredient that can help stabilize formulas but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragranceantioxidant
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Fragrance Ingredient

M-Tert-Butylphenyl Isobutyraldehyde

M-TERT-BUTYLPHENYL ISOBUTYRALDEHYDE

2.0

A synthetic fragrance ingredient that is increasingly restricted due to potential skin sensitization and reproductive toxicity concerns.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

M-Tolualdehyde

M-Tolualdehyde

3.0

M-Tolualdehyde is a synthetic fragrance compound that adds almond-like notes but may cause skin irritation in sensitive individuals.

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Antioxidant

Maackia Fauriei Branch Extract

Maackia Fauriei Branch Extract

3.8

A gentle botanical extract with antioxidant potential, but research is limited and benefits are not yet well-established in human skin.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Emollient

Maackia Fauriei Leaf Oil

MAACKIA FAURIEI LEAF OIL

3.5

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

Irritation

low

Source

natural

beautyskincarebotanical oil
Read ingredient review

Antioxidant

Maackia Fauriei Stem Extract

Maackia Fauriei Stem Extract

3.8

A gentle plant extract with antioxidant potential, but research is still early — it's more of a supporting ingredient than a star performer.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Antioxidant

Maackiasin

Maackiasin

3.8

Maackiasin is a plant-derived antioxidant that may help protect skin from environmental stress, but research is still early.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Soothing Agent

Maca & Sarcodon Root Water

LEPIDIUM MEYENII/SARCODON ASPRATUS ROOT WATER

3.8

A gentle, water-based botanical blend that may offer antioxidant and soothing benefits, but research is limited.

Irritation

low

Source

natural

beautyskincaresoothing
Read ingredient review

Antioxidant

Maca Root Powder

LEPIDIUM MEYENII ROOT POWDER

3.8

Maca root powder is a gentle, antioxidant-rich botanical that may help soothe and protect skin, but research on its topical benefits is still limited.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Surfactant

Macadamia Amidopropyl Betaine

MACADAMIAMIDOPROPYL BETAINE

4.0

A mild, coconut- and macadamia-derived surfactant that cleanses gently, making it a good choice for sensitive or dry skin.

Irritation

low

Source

semi-synthetic

beautyskincarecleanser
Read ingredient review

Emollient

Macadamia Oil PEG-8 Esters

MACADAMIA TERNIFOLIA SEED OIL PEG-8 ESTERS

4.0

A gentle, water-friendly emollient that softens skin without feeling greasy, but the PEG modification may raise concerns for some sensitive users.

Irritation

low

Source

semi-synthetic

beautyskincareemollient
Read ingredient review

Emollient

Macadamia Seed Extract

Macadamia Ternifolia Seed Extract

4.0

A gentle, fatty-acid-rich extract that hydrates and softens skin without clogging pores.

Irritation

low

Source

natural

beautyskincareemollient
Read ingredient review

Emollient

Macadamia Seed Oil

MACADAMIA INTEGRIFOLIA/TETRAPHYLLA SEED OIL

4.3

A non-greasy, nutrient-rich oil that hydrates and softens skin without clogging pores, ideal for dry or mature skin.

Irritation

low

Source

natural

beautyskincareemollient
Read ingredient review

Exfoliant

Macadamia Shell Powder

MACADAMIA TERNIFOLIA SHELL POWDER

3.8

A gentle, natural exfoliant that sloughs off dead skin cells without harsh microplastics, but may feel too gritty for sensitive skin.

Irritation

low

Source

natural

beautyskincareexfoliant
Read ingredient review

Emollient

Macauba Palm Seed Butter

Acrocomia Aculeata Seed Butter

4.0

A nourishing plant butter that softens and hydrates skin without feeling overly greasy, but research on its specific benefits is still limited.

Irritation

low

Source

natural

beautyskincareemollient
Read ingredient review

Antioxidant

Mace Lignan Extract

Myristica fragrans (Nutmeg) Extract (and) Macelignan

3.8

A promising antioxidant from nutmeg that may help protect skin from environmental stress, but research is still early.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Fragrance

Mace Oil

MYRISTICA FRAGRANS ARIL OIL

3.5

Mace oil adds a warm, spicy scent to products and offers antioxidant benefits, but its potency means it can irritate sensitive skin if used too strong.

Irritation

moderate

Source

natural

beautyskincarefragrance
Read ingredient review

Antioxidant

Machilus Bark Extract

Machilus Odoratissima Bark Extract

3.8

A gentle plant extract with antioxidant potential, but research is limited and benefits are not yet well-established.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Antioxidant

Machilus Thunbergii Branch Extract

Machilus Thunbergii Branch Extract

3.8

A gentle botanical extract with antioxidant potential, but research is still early and benefits are not yet proven in human skin.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Emollient

Machilus Thunbergii Seed Oil

Machilus Thunbergii Seed Oil

3.8

A gentle, non-greasy oil that helps soften and soothe skin, but research on its unique benefits is still limited.

Irritation

low

Source

natural

beautyskincareemollient
Read ingredient review

Antioxidant

Maclura Aurantiaca Wood Extract

Maclura Aurantiaca Wood Extract

3.8

A plant-based antioxidant extract that may help protect skin from environmental stress, but research is still early.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Antioxidant

Maclura Pomifera Fruit Extract

MACLURA POMIFERA FRUIT 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
Read ingredient review

Antioxidant

Macropiper Excelsum Leaf Extract

MACROPIPER EXCELSUM LEAF EXTRACT

3.8

A gentle botanical extract with antioxidant potential, but research is limited and it's not a powerhouse ingredient on its own.

Irritation

low

Source

natural

beautyskincarebotanical extract
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Antioxidant

Macropiper Excelsum Leaf Powder

MACROPIPER EXCELSUM LEAF POWDER

3.8

A gentle botanical powder with traditional soothing and antioxidant potential, but scientific research on its cosmetic benefits is still limited.

Irritation

low

Source

natural

beautyskincarebotanical
Read ingredient review

Antioxidant

Macrotomia Euchroma Root Extract

Macrotomia Euchroma Root Extract

3.8

A gentle, plant-derived antioxidant that may help calm skin and fight environmental stress, but research is still early.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

Soothing agent

Madecassic Acid

Madecassic Acid

4.3

Madecassic acid is a soothing, skin-repairing compound from Centella asiatica that helps calm irritation and support the skin barrier.

Irritation

low

Source

natural

beautyskincaresoothing agent
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Soothing agent

Madecassoside

MADECASSOSIDE

4.5

A gentle, research-backed soothing ingredient from cica that helps calm redness and support skin repair without irritation.

Irritation

low

Source

natural

beautyskincaresoothing agent
Read ingredient review

Soothing agent

Madonna Lily Bulb Extract

Lilium Candidum Bulb Extract

3.8

A gentle botanical extract that may help calm skin and provide antioxidant support, but research is still early.

Irritation

low

Source

natural

beautyskincarebotanical extract
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Antioxidant

Madonna Lily Callus Extract

Lilium Candidum Callus Culture Extract

4.0

A gentle, lab-grown lily extract that may help calm skin and fight environmental stress, but research is still early.

Irritation

low

Source

biotech

beautyskincareantioxidant
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Antioxidant

Madonna Lily Callus Ferment

SACCHAROMYCES/LILIUM CANDIDUM CALLUS EXTRACT FERMENT EXTRACT FILTRATE

3.8

A gentle, biotech-derived ingredient that may help calm and protect skin, though human studies are still limited.

Irritation

low

Source

biotech

beautyskincareantioxidantsoothing
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Soothing Agent

Madonna Lily Flower Extract

Lilium Candidum Flower Extract

3.8

A gentle botanical extract that may help calm skin and provide antioxidant support, though research on its cosmetic benefits is still limited.

Irritation

low

Source

natural

beautyskincarebotanical
Read ingredient review

Fragrance

Madonna Lily Flower Water

LILIUM CANDIDUM FLOWER WATER

3.8

A gentle, lightly astringent floral water that adds a subtle lily scent and soothing feel to skincare products, but has limited research on specific skin benefits.

Irritation

low

Source

natural

beautyskincarebotanical extract
Read ingredient review

Antioxidant

Madonna Lily Leaf Cell Extract

Lilium Candidum Leaf Cell Extract

3.8

A gentle, plant-derived antioxidant that may help protect skin from environmental stress, though research is still emerging.

Irritation

low

Source

biotech

beautyskincareantioxidant
Read ingredient review

Antioxidant

Madrox

MADROX

3.0

Madrox is a little-known ingredient with minimal published research; its benefits are unclear and it may be a trade name for a blend.

Irritation

low

Source

mixed

beautyskincareantioxidant
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Antioxidant

Maesa Japonica Extract

Maesa Japonica Extract

3.8

A gentle plant extract with antioxidant potential, but research is limited—think of it as a supportive, not star, ingredient.

Irritation

low

Source

natural

beautyskincareantioxidant
Read ingredient review

pH Adjuster

Magnesium Acetate

Magnesium Acetate

3.8

A gentle pH adjuster that helps keep your skincare products stable and skin-friendly, but offers no direct skin benefits.

Irritation

low

Source

synthetic

beautyskincarepH adjuster
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Antioxidant

Magnesium Acetylmethionate

Magnesium Acetylmethionate

4.0

A gentle antioxidant that pairs magnesium with a modified amino acid to help protect skin from environmental stress and support a healthy-looking complexion.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
Read ingredient review