The library

Ingredient library

Every ingredient SkinAtlas knows about — all 2171 of them. What each one does, what it works well with, and what to watch for.

131 ingredients matching "acid" — page 5 of 6

Humectant
Proline

A cyclic amino acid that functions as a humectant and forms part of the skin's natural moisturizing factor.

humectantamino-acid
Attracts and retains moistureSupports the skin's natural moisturizing factor (NMF)
Exfoliant
Pyruvic Acid

An alpha-keto acid naturally occurring in the body's metabolic pathway, used in cosmetics at low concentrations as a keratolytic exfoliant with antimicrobial and sebostatic properties; at professional peel concentrations (35–50%) it has clinical evidence for acne, photoaging, and pigmentation.

exfoliantkeratolyticantimicrobialsebostatic
Alpha-keto acid with keratolytic action that loosens bonds between dead skin cells, improving cell turnoverAntimicrobial and sebostatic properties useful for acne-prone and oily skinStimulates new collagen and elastin synthesis, supporting anti-aging and firmness
Strong acid (pKa ~2.39); at high concentrations (>40%) can cause intense burning, erythema, desquamation, and crustingConcentrations used in professional peels are much higher than leave-on cosmetics — leave-on formulas typically use low percentages with buffering
Other
Red 33
RED 33

A synthetic monoazo dye (CI 17200) used to give pink or red hues to toners, essences, and rinse-off products. Cosmetic-grade; not approved for use near the eyes in all markets.

colorant
Provides pink-to-red tint in cosmetic formulas
Rare azo-dye sensitisation in susceptible individuals
Exfoliant
Salicylic Acid

An oil-soluble BHA that exfoliates inside the pore.

bha
Unclogs poresReduces blackheadsAnti-inflammatory
Can be dryingSun sensitivity
× Retinol× Retinal
Humectant
Serine

A naturally occurring amino acid that functions as a humectant and is a component of the skin's natural moisturizing factor.

humectantamino-acid
Attracts and retains moistureSupports the skin's natural moisturizing factor (NMF)
Humectant
Silk Amino Acids

The amino acid fraction obtained by hydrolysis of silk fibroin, the structural protein of silk from Bombyx mori silkworm cocoons. Rich in glycine (~46%), serine (~12%), and alanine (~29%). Distinct from 'Hydrolyzed Silk' (which refers to larger peptide fragments), though both are derived from the same source. Absorbs into skin to replenish NMF components and provides a smooth, slightly substantive skin feel.

humectantfilm-formingskin-conditioning
Low-molecular-weight amino acids from hydrolyzed silk fibroin absorb readily into skin, providing deep moisture bindingRich in serine, glycine, and alanine — skin-identical amino acids that act as natural moisturizing factor (NMF) componentsForms a light, semi-permeable film on the skin surface that reduces TEWL while retaining a non-tacky, smooth finish
Silk-derived — individuals with silk allergies or sensitivities should patch test
+ Sodium Hyaluronate+ Glycerin+ Panthenol
Other
Sodium Acrylic Acid/MA Copolymer

A sodium salt copolymer of acrylic acid and maleic acid (MA) used as a polymeric thickener and rheology modifier in cosmetic creams, lotions, and serums.

thickenerfilm-formerviscosity-modifier
Provides stable viscosity and gel texture in aqueous formulationsFilm-forming properties improve product spreadabilityCompatible with a wide pH range
Preservative
Sodium Anisate

The sodium salt of p-anisic acid (naturally derived from fennel/anise), used as a mild preservative that inhibits yeast and fungal growth in cosmetic formulations.

preservativemaskingfragrance
Prevents microbial growth (yeast and fungi)Gentle natural-derived preservative suitable for sensitive skinBiodegradable and low irritation potential
Most effective at pH 4.5–5.5; reduced efficacy outside that rangeBest used in combination with other preservatives rather than as a standalone system
Antioxidant
Sodium Ascorbate
SODIUM ASCORBATE

The sodium salt of ascorbic acid (vitamin C). More stable and less acidic than pure ascorbic acid, with a neutral pH. Used as an antioxidant and brightening agent in skincare. Found in Sana's eye cream.

antioxidantskin-brightening
Water-soluble vitamin C — antioxidant protectionSupports collagen synthesisSkin brightening
Less potent than ascorbic acid at equal concentrations — requires higher loading for brightening
+ Tocopherol+ Niacinamide+ Ferulic Acid
Humectant
Sodium Aspartate

The sodium salt of the amino acid aspartic acid, used as a humectant and skin-conditioning agent that helps maintain skin hydration.

humectantskin-conditioning
Attracts and retains moisture in skinAmino acid derivative that supports skin's natural moisturizing factors
Humectant
Sodium Carboxymethyl Hyaluronate
SODIUM CARBOXYMETHYL HYALURONATE

Carboxymethylated hyaluronic acid — a modified form of sodium hyaluronate where additional carboxymethyl groups are added to the backbone. Enhanced adherence to the skin surface vs. standard HA. Used in Matsuyama's Hadauru toner for superior hydration.

humectantfilm-former
Modified hyaluronic acid with enhanced skin adherenceSuperior moisture retentionFilm-forming barrier support
+ Sodium Hyaluronate+ Natto Gum
Surfactant
Sodium Cocoyl Apple Amino Acids

A mild amino acid-based surfactant formed from coconut-derived fatty acids conjugated with amino acids from hydrolyzed apple protein, used in gentle cleansing formulations.

SurfactantCleansingFoaming agentSkin conditioning
Extremely mild, amino acid-derived surfactantApple-sourced amino acids improve skin compatibilitySuitable for sensitive skin formulations
Very low risk profile; among the gentlest surfactants available
Other
Sodium Glycolate

The sodium salt of glycolic acid. Functions primarily as a pH-buffering and stabilizing agent in cosmetic formulas.

bufferingpH-adjusting
Sodium salt of glycolic acid functioning as a pH buffer and processing aidMay contribute minimal exfoliating or chelating activity as a glycolate salt
Surfactant
Sodium Myristoyl Glutamate

An amino acid-derived anionic surfactant produced by condensing myristic acid (C14) with glutamic acid, used in gentle cleansers for mild, effective foaming with a favorable skin-compatibility profile.

cleansingfoamingsurfactant
Amino acid-derived surfactant with gentle cleansing actionBiodegradable and skin-compatibleProduces smooth, dense foam
Minimal; similar safety profile to other amino acid surfactants
Other
Sodium Phytate

A natural chelating agent derived from rice bran or corn that stabilizes formulas by sequestering trace metals and boosting preservative performance.

chelatorpreservative-booster
Binds trace metal ions (iron, copper, calcium) to prevent oxidation and formula degradationBoosts preservative efficacy by making the environment hostile to microbesBiodegradable alternative to synthetic EDTA
Humectant
Sodium Polyglutamate

A fermentation-derived polymer (from natto) that binds water and forms a light moisturizing film, often described as more hydrating than hyaluronic acid by weight.

humectantfilm-forming
Strong humectant hydrationSmooth, soft film on skin
Low risk
+ Sodium Hyaluronate+ Glycerin
Other
Sodium RNA

The sodium salt of ribonucleic acid (RNA), used as a skin-conditioning agent that improves the feel and suppleness of skin in cosmetic formulations.

skin-conditioning
Skin conditioning; leaves skin softer and smootherNon-comedogenic
Preservative
Sorbic Acid

A straight-chain unsaturated carboxylic acid used as a cosmetic preservative at up to 1% concentration to prevent microbial contamination and extend product shelf life.

preservative
Broad-spectrum preservative effective against mold, yeast, and bacteriaWell-studied safety profile; CIR Expert Panel assessed as safe up to 1% in cosmetics
Rare non-immunological contact urticaria and pseudo-allergic reactions reported in humansEWG score of 3 out of 10 (moderate concern)
Emollient
Stearic Acid

A saturated C18 fatty acid used as an emollient, emulsifier and thickener that gives creams a rich texture.

emollientemulsifierthickener
Softens and conditions skinStabilizes emulsionsAdds body to creams
Surfactant
Stearoyl Glutamic Acid

A fatty acid-amino acid conjugate (stearic acid + glutamic acid) used as a mild emulsifier and skin-conditioning agent, particularly common in Japanese sunscreen formulations.

emulsifierskin-conditioning
Acts as an amino acid-derived emulsifier with good skin compatibilityProvides a smooth, non-greasy skin feel
Other
Succinic Acid

A naturally occurring dicarboxylic acid used in cosmetics primarily as a pH adjuster and mild chelating agent, with secondary humectant properties.

ph-adjusterchelatorhumectant
Adjusts and stabilizes formula pHMild chelating agentLight humectant properties
Emollient
Sucrose Cocoate

A mixture of sucrose esters of coconut fatty acids used as a mild emollient, emulsifier, and gentle surfactant in skin care products; well-tolerated and considered skin-friendly.

emollientsurfactantemulsifier
Provides skin-softening emolliency from the fatty acid esterMild surfactant action for gentle cleansingPlant-derived and biodegradable
Antioxidant
Tannic Acid

A plant-derived polyphenol (from oak bark, chestnut, and other sources) with astringent, antioxidant, and anti-inflammatory properties used in pore-refining and soothing formulations.

astringentantioxidantantimicrobialskin-conditioning
Tightens skin and reduces appearance of pores via astringent actionProtects skin from oxidative stress as a polyphenol antioxidantAnti-inflammatory: calms redness and irritation
May cause dryness or irritation at high concentrationsCan be sensitizing for very sensitive skin types
Exfoliant
Tartaric Acid

A naturally occurring alpha-hydroxy acid (AHA) found in grapes and wine, used in cosmetics for its mild exfoliating, pH-buffering, and antioxidant properties; gentler than glycolic acid due to its larger molecular size and slower skin penetration.

exfoliantpH adjusterchelating agentantioxidant
AHA exfoliant derived primarily from grapes and wine; loosens dead skin cells to improve texture and toneLarger molecular size than glycolic or malic acid results in slower, more superficial penetration — gentler exfoliation profileContributes to pH stabilization in formulations, enhancing the effectiveness of other AHAs
At high concentrations may cause irritation, stinging, or adverse reactions like other AHAsIncreases photosensitivity; daily SPF use recommended when using exfoliant-containing products