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 1,094
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

Humectant

Lactulose

Lactulose

3.8

Lactulose is a gentle sugar-derived humectant that also acts as a prebiotic, helping to support a balanced skin microbiome without irritation.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
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Humectant

Laminaria Cloustoni Extract

Laminaria Cloustoni Extract

4.0

A gentle, mineral-rich seaweed extract that helps hydrate and calm the skin without clogging pores.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Laminaria Hyperborea Extract

Laminaria Hyperborea Extract

4.0

A nutrient-rich seaweed extract that hydrates, soothes, and protects the skin with antioxidants, ideal for dry or sensitive skin types.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Laminaria Japonica Powder

Laminaria Japonica Powder

4.0

A gentle seaweed powder that helps hydrate and calm the skin while providing antioxidant protection.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Laminaria Longissima Extract

Laminaria Longissima Extract

4.0

A gentle, mineral-rich seaweed extract that hydrates and soothes the skin, ideal for sensitive or dry types.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Laminaria Ochotensis Extract

Laminaria Ochotensis Extract

4.0

A gentle seaweed extract that hydrates and soothes skin, but its benefits are mostly backed by traditional use and limited clinical studies.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Laminaria Ochroleuca Extract

Laminaria Ochroleuca Extract

4.0

A gentle, mineral-rich seaweed extract that hydrates and soothes skin, ideal for sensitive or dry types.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Laminaria Saccharina Extract

Laminaria Saccharina Extract

4.0

A gentle, nutrient-rich seaweed extract that hydrates and soothes the skin, with antioxidant benefits to help protect against environmental stress.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Lentil Seed Extract

Lens Culinaris Seed Extract

4.0

A gentle, plant-based humectant that helps hydrate and soothe the skin, with antioxidant benefits.

Irritation

low

Source

natural

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Humectant

Leucine

LEUCINE

4.0

Leucine is a gentle amino acid that supports skin hydration and barrier health, making it a safe addition to most routines.

Irritation

low

Source

natural

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Humectant

Levan

Levan

4.0

Levan is a gentle, biotech-derived humectant that helps hydrate and soothe skin while forming a lightweight protective film.

Irritation

low

Source

biotech

beautyskincarehumectantfilm-former
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Humectant

Levan Sugar Complex

LEVAN/FRUCTOSE/GLUCOSE/SUCROSE

4.0

A gentle sugar-based blend that hydrates and helps form a protective layer on skin, suitable for most skin types.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Lindera Leaf/Twig Water

Lindera Umbellata Leaf/Twig Water

3.8

A gentle, hydrating botanical water that can replace plain water in formulas, offering mild soothing and antioxidant benefits.

Irritation

low

Source

natural

beautyskincarehumectantsoothing
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Humectant

Lithium Chloride

Lithium Chloride

2.0

Lithium chloride is a synthetic salt with humectant properties, but it is rarely used in mainstream skincare due to potential irritation and limited research on cosmetic benefits.

Irritation

moderate

Source

synthetic

beautyskincarehumectant
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Soothing Agent

Lotus Flower Water

Nelumbo Nucifera Flower Water

4.0

Lotus flower water is a mild, hydrating botanical water that soothes skin and adds a subtle floral scent, but its benefits beyond basic moisture are not strongly backed by research.

Irritation

low

Source

natural

beautyskincaresoothinghumectant
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Humectant

Lotus Root Water

Nelumbo Nucifera Root Water

4.0

A gentle, antioxidant-rich water that hydrates and soothes the skin, ideal for sensitive or dry types.

Irritation

low

Source

natural

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Humectant

Luffa Cylindrica Stem Sap

LUFFA CYLINDRICA STEM SAP

3.8

A gentle, plant-derived humectant that helps hydrate and calm the skin, though research is still emerging.

Irritation

low

Source

natural

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Humectant

Luffa Fruit Water

Luffa Cylindrica Fruit Water

3.8

Luffa fruit water is a mild, plant-derived hydrator that can soothe and refresh skin, but it has limited research and is not a powerhouse active.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Lychee Fruit Juice

Litchi Chinensis Fruit Juice

3.8

Lychee fruit juice is a gentle, water-based ingredient that adds light hydration and antioxidant protection, but its benefits are not as well-studied as more common fruit extracts.

Irritation

low

Source

natural

beautyskincarehumectantantioxidant
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Humectant

Lysine

Lysine

4.0

Lysine is a gentle amino acid that helps hydrate and support the skin's natural barrier, making it a safe addition to most routines.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Lysine Aspartate

Lysine Aspartate

4.0

Lysine Aspartate is a mild amino-acid salt that helps attract moisture to the skin and supports a healthy barrier, making it a gentle option for most skin types.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
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Humectant

Magnesium Aspartate

Magnesium Aspartate

4.0

Magnesium Aspartate is a gentle, hydrating mineral salt that helps support skin barrier function and soothe irritation.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
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Humectant

Magnesium Citrate

Magnesium Citrate

3.8

Magnesium citrate is a gentle, water-soluble salt that can help exfoliate and hydrate skin without the irritation of stronger acids.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

Magnesium Glucoheptonate

Magnesium Glucoheptonate

3.8

A gentle humectant that pulls moisture into the skin and may help calm irritation, but research is still limited.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

Magnesium Lactate

MAGNESIUM LACTATE

4.0

A gentle, hydrating magnesium salt that supports skin barrier function without clogging pores.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

Malt Extract

MALT EXTRACT

4.0

Malt extract is a gentle, natural humectant that helps hydrate and soothe the skin, making it a good choice for sensitive or dry skin types.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Maltitol

Maltitol

3.8

Maltitol is a gentle humectant that helps hydrate skin and improve product texture, but it offers no unique advantage over more common alternatives like glycerin.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
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Exfoliant

Maltobionic Acid

Maltobionic Acid

4.3

A mild, hydrating exfoliant ideal for sensitive skin, offering gentle surface renewal without the sting of stronger acids.

Irritation

low

Source

natural

beautyskincareexfolianthumectant
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Humectant

Maltodextrin

MALTODEXTRIN

3.8

Maltodextrin is a gentle, sugar-derived ingredient that helps products feel smooth and slightly hydrating without clogging pores.

Irritation

low

Source

natural

beautyskincarehumectanttexture enhancer
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Humectant

Maltooligosyl Glucoside

Maltooligosyl Glucoside

4.2

A mild, sugar-based humectant that pulls water into the skin without stickiness, making it a great alternative to glycerin for lightweight hydration.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
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Humectant

Maltose

MALTOSE

4.0

Maltose is a gentle, natural humectant that helps attract and hold moisture in the skin without irritation or clogging pores.

Irritation

low

Source

natural

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Humectant

Mangosteen Amino Acids

GARCINIA MANGOSTANA AMINO ACIDS

4.0

A gentle, plant-based amino acid blend that helps hydrate and support the skin barrier, though research is still emerging.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Mannan

Mannan

4.0

Mannan is a gentle, plant-derived sugar that helps hydrate and soothe skin by forming a protective film.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Mannitol

Mannitol

4.0

Mannitol is a gentle, water-binding sugar alcohol that helps hydrate skin and offers mild antioxidant protection without irritation.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Mannose

Mannose

4.0

Mannose is a gentle sugar humectant that helps hydrate skin by attracting moisture, with some research suggesting it may support collagen production.

Irritation

low

Source

natural

beautyskincarehumectant
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Humectant

Maple Sap Extract

Acer Saccharum Sap Extract

4.0

A gentle, natural humectant that hydrates and soothes skin without clogging pores, ideal for sensitive and dry skin types.

Irritation

low

Source

natural

beautyskincarehumectant
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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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Humectant

Melibiose

Melibiose

4.0

Melibiose is a gentle sugar humectant that helps hydrate the skin and may support a healthy skin microbiome, making it a promising alternative to traditional humectants.

Irritation

low

Source

natural

beautyskincarehumectant
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Cooling Agent

Menthyl PCA

Menthyl PCA

4.0

Menthyl PCA offers a gentle, long-lasting cooling sensation without the strong minty odor of menthol, while also helping to hydrate the skin.

Irritation

low

Source

semi-synthetic

beautyskincarecooling agenthumectant
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Humectant

Methoxy PEG-10

METHOXY PEG-10

3.5

Methoxy PEG-10 is a gentle, water-attracting polymer that helps keep skin hydrated and improves product texture, but it is synthetic and may be a concern for those avoiding PEGs.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Solvent

Methoxy PEG-100

METHOXY PEG-100

3.5

A synthetic humectant that helps dissolve other ingredients and retain moisture, but offers no unique benefits over gentler alternatives.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

Methoxy PEG-144

Methoxy PEG-144

3.5

A gentle, water-binding ingredient that helps keep products stable and skin hydrated, but its synthetic origin may not appeal to everyone.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

Methoxy PEG-16

METHOXY PEG-16

3.5

A gentle, water-attracting polymer that helps keep skin hydrated without clogging pores, but may not suit those avoiding all PEGs.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

Methoxy PEG-25

METHOXY PEG-25

3.5

A synthetic humectant that helps keep skin hydrated and improves product texture, but may be less eco-friendly due to its PEG origin.

Irritation

low

Source

synthetic

beautyskincarehumectant
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Humectant

Methoxypropylgluconamide

Methoxypropylgluconamide

4.2

A gentle, sugar-based humectant that hydrates without stickiness, suitable for most skin types including sensitive skin.

Irritation

low

Source

semi-synthetic

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Humectant

Methyl Aspartic Acid

METHYL ASPARTIC ACID

3.8

A gentle, synthetic amino acid derivative that may help hydrate and support the skin barrier, but research is still emerging.

Irritation

low

Source

synthetic

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Humectant

Methyl Gluceth-20

METHYL GLUCETH-20

4.5

A mild, non-sticky humectant that pulls water into the skin, making it a great alternative to glycerin for those who dislike tackiness.

Irritation

low

Source

semi-synthetic

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Humectant

Methyl Glutamic Acid

Methyl Glutamic Acid

3.8

A gentle, synthetic amino acid that helps hydrate and condition skin, but research on its benefits is still limited compared to more established humectants.

Irritation

low

Source

synthetic

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Humectant

Methyl Isobutyl Glycerol Formal

METHYL ISOBUTYL GLYCEROL FORMAL

4.0

A gentle synthetic humectant that helps hydrate skin without the sticky feel of glycerin, making it a good option for lightweight formulas.

Irritation

low

Source

synthetic

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Humectant

Methyl Lactate

METHYL LACTATE

3.8

Methyl lactate is a mild humectant that helps hydrate skin without the sting often associated with pure lactic acid, making it a good option for sensitive skin.

Irritation

low

Source

semi-synthetic

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Humectant

Methylhydantoin-Imide

1-METHYLHYDANTOIN-2-IMIDE

3.5

A synthetic humectant that helps skin retain moisture, but research on its long-term effects is still limited.

Irritation

low

Source

synthetic

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Humectant

Methylpropanediol

Methylpropanediol

4.2

A lightweight, low-irritation humectant that helps products feel silky and can boost preservative power without adding stickiness.

Irritation

low

Source

synthetic

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Humectant

Methylserine

Methylserine

3.8

Methylserine is a gentle, water-attracting amino acid derivative that helps hydrate and condition the skin, but research on its long-term benefits is still limited.

Irritation

low

Source

synthetic

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