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

Fragrance Ingredient

Acetaldehyde Phenethyl Propyl Acetal

ACETALDEHYDE PHENETHYL PROPYL ACETAL

3.5

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

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Humectant

Acetamide MEA

ACETAMIDE MEA

3.8

Acetamide MEA is a synthetic humectant that helps hydrate skin and hair, but it is less common than alternatives like glycerin and may not suit those avoiding synthetic ingredients.

Irritation

low

Source

synthetic

beautyskincarehumectant
Read ingredient review

Humectant

Acetamidoethoxyethanol

Acetamidoethoxyethanol

4.0

A gentle, synthetic humectant that helps hydrate the skin without common irritation or clogging.

Irritation

low

Source

synthetic

beautyskincarehumectant
Read ingredient review

Antistatic Agent

Acetamidoethyl PG-Trimonium Chloride

Acetamidoethyl PG-Trimonium Chloride

4.0

A gentle synthetic conditioning ingredient that reduces frizz and static while improving the feel of hair and skin without heavy buildup.

Irritation

low

Source

synthetic

beautyskincarehaircareconditioning agent
Read ingredient review

Antistatic Agent

Acetamidopropyl Trimonium Chloride

Acetamidopropyl Trimonium Chloride

4.0

A gentle antistatic ingredient that smooths hair without heavy buildup, making it a good choice for fine or easily weighed-down hair.

Irritation

low

Source

synthetic

beautyskincarehaircare
Read ingredient review

UV Absorber

Acetaminosalol

Acetaminosalol

3.5

Acetaminosalol is a synthetic UV filter that helps protect skin from sun damage, but it may cause irritation for sensitive skin types.

Irritation

moderate

Source

synthetic

beautyskincaresunscreen
Read ingredient review

pH Adjuster

Acetic Acid

Acetic Acid

3.5

Acetic acid is a gentle exfoliant and pH adjuster, but can be irritating at high concentrations.

Irritation

moderate

Source

natural

beautyskincarepH adjuster
Read ingredient review

Film Former

Acetiminoacetoxy Methacrylate Polymer

TRIS(ACETIMINOACETOXYETHOXY METHACRYLATE) PPG-6 TRIMETHYLOLPROPANE

3.5

A synthetic film former that helps products stay put, but it's mostly used in specialty items like nail polish rather than everyday skincare.

Irritation

low

Source

synthetic

beautyskincarefilm-former
Read ingredient review

Humectant

Acetoin

Acetoin

4.0

Acetoin is a gentle, natural humectant that helps hydrate skin and improve product texture without irritation.

Irritation

low

Source

natural

beautyskincarehumectant
Read ingredient review

Fragrance

Acetonaphthone

1-ACETONAPHTHONE

3.0

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

Irritation

moderate

Source

synthetic

beautyskincarefragrance
Read ingredient review

Solvent

Acetone

Acetone

2.0

Acetone is a powerful but harsh solvent best reserved for quick, targeted removal of nail polish or stubborn adhesives, not for daily facial skincare.

Irritation

high

Source

synthetic

beautyskincaresolvent
Read ingredient review

Fragrance Ingredient

Acetophenone

ACETOPHENONE

3.5

Acetophenone is a synthetic fragrance ingredient that adds a sweet, almond-like scent; it is generally considered safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Acetophenone Ethylene Glycol Cyclic Acetal

ACETOPHENONE ETHYLENEGLYCOL CYCLIC ACETAL

3.5

A synthetic fragrance compound that adds a pleasant scent but offers no skincare benefits; safe at low concentrations but may cause sensitivity in some individuals.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance

Acetoxymethylnaphthalene

1-ACETOXY-2-METHYLNAPHTHALENE

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

Humectant

Acetyl Arginine

Acetyl Arginine

4.0

A gentle, water-loving amino acid derivative that helps plump skin and support its natural moisture barrier without irritation.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
Read ingredient review

Humectant

Acetyl Aspartic Acid

Acetyl Aspartic Acid

3.8

Acetyl Aspartic Acid is a gentle, water-soluble amino acid derivative that helps maintain skin hydration and supports a healthy skin barrier.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
Read ingredient review

Skin conditioning agent

Acetyl Benzoyloxy Prasterone

ACETYL BENZOYLOXY PRASTERONE

3.5

A synthetic hormone derivative that may help support skin firmness, but research is limited and it may not suit sensitive skin.

Irritation

moderate

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Anti-aging agent

Acetyl Beta-Alanyl Tripeptide-50

Acetyl Beta-Alanyl Tripeptide-50

4.0

A synthetic peptide that may help improve skin firmness and reduce fine lines, but more independent research is needed.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Surfactant

Acetyl Carboxymethyl Cocoyl Glycine

Acetyl Carboxymethyl Cocoyl Glycine

4.0

A mild, coconut-derived cleansing agent that effectively removes dirt and oil without stripping the skin’s natural moisture barrier.

Irritation

low

Source

semi-synthetic

beautyskincarecleanser
Read ingredient review

Antioxidant

Acetyl Carnitine

Acetyl Carnitine

4.0

Acetyl Carnitine is a gentle antioxidant that may help protect skin from environmental stress and support collagen health, but research is still emerging.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
Read ingredient review

Antioxidant

Acetyl Carnitine HCl

ACETYL CARNITINE HCL

3.8

Acetyl Carnitine HCl is a gentle antioxidant that may help protect skin from environmental stress and support a more even tone, though it is not as well-studied as vitamin C or niacinamide.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
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Antioxidant

Acetyl Carnosine

Acetyl Carnosine

4.0

A stable antioxidant peptide that helps protect skin from environmental damage and may support a more youthful appearance.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
Read ingredient review

Skin conditioning agent

Acetyl Citrull Amido Arginine

Acetyl Citrull Amido Arginine

4.0

A gentle amino-acid derivative that may help support skin firmness and resilience, though research is still emerging.

Irritation

low

Source

semi-synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Cyclohexapeptide-34

Acetyl Cyclohexapeptide-34

4.0

A lab-made peptide that may help smooth fine lines and improve skin firmness, but human studies are limited.

Irritation

low

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Antioxidant

Acetyl Cysteine

ACETYL CYSTEINE

3.8

Acetyl Cysteine is a promising antioxidant and brightening ingredient, but research in topical skincare is still emerging compared to more established options like vitamin C.

Irritation

low

Source

semi-synthetic

beautyskincareantioxidant
Read ingredient review

Skin conditioning agent

Acetyl Decapeptide-3

Acetyl Decapeptide-3

4.0

A synthetic peptide that may help reduce the appearance of fine lines and improve skin firmness with consistent use.

Irritation

low

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Anti-aging agent

Acetyl Dipeptide-3 Aminohexanoate

Acetyl Dipeptide-3 Aminohexanoate

3.8

A synthetic peptide that may help soften expression lines by temporarily relaxing facial muscles, similar to a milder, topical alternative to injectables.

Irritation

low

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Anti-aging agent

Acetyl Dipeptide-31 Amide

ACETYL DIPEPTIDE-31 AMIDE

4.0

A synthetic peptide that may help soften expression lines and improve skin firmness with minimal irritation risk.

Irritation

low

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Moisturizer

Acetyl Dipeptide-32 Amide

Acetyl Dipeptide-32 Amide

4.0

A gentle peptide that helps strengthen the skin barrier and soften the look of expression lines over time.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Skin conditioning agent

Acetyl Farnesylcysteine

Acetyl Farnesylcysteine

3.5

A synthetic peptide-like ingredient that may help support skin firmness, but research is still early and benefits are not yet proven in large human studies.

Irritation

low

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Humectant

Acetyl Galactosamine

Acetyl Galactosamine

3.8

A gentle sugar-derived ingredient that supports skin renewal and surface smoothness, often used as a milder alternative to traditional exfoliants.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
Read ingredient review

Humectant

Acetyl Glucosamine

Acetyl Glucosamine

4.2

A mild, sugar-based ingredient that helps gently exfoliate and hydrate skin without the harshness of stronger acids.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
Read ingredient review

Humectant

Acetyl Glutamine

Acetyl Glutamine

4.0

Acetyl Glutamine is a gentle, water-loving amino acid derivative that helps keep skin plump and hydrated while supporting the skin's natural barrier.

Irritation

low

Source

semi-synthetic

beautyskincarehumectant
Read ingredient review

Skin conditioning agent

Acetyl Glycyl Beta-Alanine

Acetyl Glycyl Beta-Alanine

3.8

A gentle peptide that helps maintain skin hydration and firmness, but research is still early.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Heptapeptide-19 Amide

ACETYL HEPTAPEPTIDE-19 AMIDE

4.0

A synthetic peptide that may help support skin firmness and reduce fine lines, with low irritation risk.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Heptapeptide-4

ACETYL HEPTAPEPTIDE-4

4.0

A synthetic peptide that may help soften expression lines by temporarily relaxing facial muscles, similar to but milder than neuropeptides.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Heptapeptide-9

ACETYL HEPTAPEPTIDE-9

4.0

A synthetic peptide that mimics natural signals to encourage firmer, smoother skin with low irritation risk.

Irritation

low

Source

synthetic

beautyskincareanti-aging
Read ingredient review

Fragrance Ingredient

Acetyl Hexamethyl Indan

ACETYL HEXAMETHYL INDAN

3.5

A synthetic musk-like fragrance ingredient that is generally considered safe at low concentrations but offers no skincare benefit beyond scent.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Fragrance Ingredient

Acetyl Hexamethyl Tetralin

ACETYL HEXAMETHYL TETRALIN

3.5

A common synthetic musk fragrance that adds a warm, sweet scent but has raised some environmental and allergen concerns.

Irritation

low

Source

synthetic

beautyskincarefragrance
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-1

ACETYL HEXAPEPTIDE-1

4.0

A synthetic peptide that may help soften expression lines by temporarily relaxing facial muscles, similar to a milder, topical version of neuromodulators.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-19

Acetyl Hexapeptide-19

3.8

A synthetic peptide that may help soften expression lines and improve skin firmness, but research is still early.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging

Acetyl Hexapeptide-20

Acetyl Hexapeptide-20

3.8

A synthetic peptide that may help soften expression lines and improve skin firmness, but research is still early.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-24

Acetyl Hexapeptide-24

4.0

A synthetic peptide that may help soften expression lines and improve skin firmness, but results are subtle and require consistent use.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging

Acetyl Hexapeptide-24 Amide

Acetyl Hexapeptide-24 Amide

4.0

A synthetic peptide that may help soften expression lines and support firmer-looking skin with low irritation risk.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-30

Acetyl Hexapeptide-30

3.8

A synthetic peptide that may help support skin firmness and reduce fine lines, but human studies are limited.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-31

ACETYL HEXAPEPTIDE-31

4.0

A synthetic peptide that may help soften expression lines by temporarily relaxing facial muscles, similar to a milder, topical version of neuromodulators.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-37

Acetyl Hexapeptide-37

3.8

A synthetic peptide that may help soften expression lines by temporarily relaxing facial muscles, similar to a milder, topical alternative to injectables.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-wrinkle agent

Acetyl Hexapeptide-38

Acetyl Hexapeptide-38

4.0

A synthetic peptide that temporarily softens expression lines by mimicking the action of a muscle-relaxing protein, offering a gentler alternative to injectables.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-wrinkle agent

Acetyl Hexapeptide-39

Acetyl Hexapeptide-39

4.0

A synthetic peptide that mimics the action of botulinum toxin to soften expression lines, but with a much milder and temporary effect.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-49

Acetyl Hexapeptide-49

4.0

A synthetic peptide that may help soften expression lines and improve skin firmness, but human data is still limited.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-51 Amide

Acetyl Hexapeptide-51 Amide

4.0

A synthetic peptide that may help support skin firmness and reduce fine lines, but research is still emerging.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-aging agent

Acetyl Hexapeptide-7

Acetyl Hexapeptide-7

4.0

A gentle peptide that may help soften expression lines over time, but results are subtle and require consistent use.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-wrinkle agent

Acetyl Hexapeptide-8

Acetyl Hexapeptide-8

4.2

A popular peptide that can soften dynamic wrinkles by relaxing facial muscles, but results are subtle and temporary.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review

Anti-wrinkle agent

Acetyl Hexapeptide-8 Amide

AMINOBUTYROYL HEXAPEPTIDE-8 AMIDE

4.0

A synthetic peptide that helps soften expression lines by temporarily relaxing facial muscles, with good safety profile but modest, temporary results.

Irritation

low

Source

synthetic

beautyskincarepeptide
Read ingredient review