Skincare Ingredients

Ammonium Polyacrylate

Ammonium polyacrylate is a high–molecular weight polymer used primarily as a thickener/film former at low concentrations (often well under 1–2%), and it is generally too large to penetrate skin and trigger true irritation in most users. Clinical experience and patch-test data for polyacrylate polymers show a low rate of irritant reactions, with occasional stinging possible on severely compromised barriers or if the finished formula’s pH/residual monomers contribute. Given the rare but plausible reactivity in highly sensitive or broken skin, it is best classified as very gentle rather than inert. Safety Notes: In mass-market leave-on lotions/serums and rinse-off cleansers, ammonium polyacrylate is most often used as a viscosity modifier/film former at very low levels (~0.05–0.3%), especially when paired with other thickeners or as part of a rheology blend. Higher-strength consumer products such as styling gels, peel-off/film-forming masks, and “gel-cream” textures can push total ammonium polyacrylate to ~1–2.5% to achieve strong yield value and continuous films, with practical upper limits driven by tack/drag, pilling risk, and electrolyte sensitivity rather than regulatory caps.

Ammonium Polyacryloyldimethyl Taurate

MVP Approved - Ammonium Polyacryloyldimethyl Taurate is a synthetic polymer used primarily as a thickener and stabilizer in cosmetic formulations, known for its overall low irritancy when properly formulated.

Amodimethicone

Amodimethicone is a conditioning silicone polymer used mainly in hair products (typically ~0.1–3%) that forms an inert, occlusive film and is not a common primary irritant in clinical or patch-test data. When reactions occur, they are usually rare and more often attributable to accompanying surfactants, fragrance, or preservatives rather than the silicone itself. For highly reactive or eczema-prone patients, I still assign a low-but-nonzero score because leave-on scalp/skin exposure can occasionally trigger follicular irritation or intolerance in a small subset. Safety Notes: In mass-market conditioners, shampoos, and rinse-off masks, amodimethicone is often used at low levels (~0.05–0.5%) as part of a silicone microemulsion/deposition system to improve slip and conditioning without heavy buildup. Leave-on sprays/creams and intensive smoothing/repair masks commonly sit around ~0.2–2% for stronger frizz control and fiber feel. High-strength consumer-available smoothing serums and concentrated mask systems can reach about 3–5% amodimethicone (usually supported by emulsifiers and amine-functional silicone compatibility aids), while higher levels are uncommon due to stability/feel and diminishing returns rather than regulatory limits.

Amorphophallus Konjac Root Powder

MVP Approved - Amorphophallus Konjac Root Powder is a natural, plant‐derived polysaccharide commonly used in skincare as a thickener and gentle texturizer, with a very low risk of irritation.

Amyl Cinnamal

Amyl Cinnamal is a fragrance allergen (cinnamal derivative) used at very low concentrations for scent, but it is a well-documented cause of allergic contact dermatitis in patch testing, especially in eczema-prone or barrier-impaired patients. Even when compliant with typical leave-on limits, real-world cumulative exposure from multiple fragranced products increases risk, and reactions can be delayed and severe in sensitized individuals. Given its primary role as fragrance (non-essential) and meaningful sensitization potential, it warrants a significant irritancy score for sensitive-skin safety. Safety Notes: Amyl Cinnamal is used in skincare primarily as a fragrance allergen component within parfum compositions, so at the low end it appears in leave-on products (e.g., face creams/serums) at trace levels around 0.1–1 ppm (0.00001–0.0001%) when present only as an impurity/constituent of a fragrance blend. In real-world OTC fragranced body lotions, body creams, deodorants, and rinse-off washes, observed levels commonly sit in the ~0.001–0.05% range, while higher-fragrance formats (fine-fragrance-adjacent body products and some strongly perfumed washes) can reach about 0.1–0.2% without being prescription/professional. Note that regulatory requirements in the EU focus on allergen labeling thresholds (0.001% leave-on; 0.01% rinse-off) rather than hard maximum limits, which is consistent with the higher end being driven by fragrance load and IFRA-style risk management.

Amylopectin

Amylopectin is a high–molecular weight starch polysaccharide used mainly as a viscosity/texture agent and film-former, typically at low percentages in leave-on or rinse-off formulas. It is generally regarded as non-irritating and is too large to penetrate skin in a way that commonly triggers stinging, but as a plant-derived polymer it can rarely cause reactivity/contamination-related sensitivity in highly eczema-prone patients. For patient safety in severely reactive skin, I rate it as exceptionally gentle rather than completely inert. Safety Notes: In commercial skincare, amylopectin is most often used as a sensory modifier/texture aid or absorbent, where it can appear at low levels (~0.05–0.5%) in serums/creams to improve slip, reduce tack, and add a soft-focus feel. Mid-range use (1–5%) is common in powders, gel-creams, and matte/blur primers for oil control and rheology. High-strength consumer products (typically loose/pressed face powders, dry shampoos, and some matte masks/primers) can reach ~10–15% as a primary absorbent/bulking component; leave-on powders tend to tolerate the highest loadings, while rinse-off formats usually sit lower due to wash-off and viscosity constraints.

Amyl Salicylate

Amyl salicylate is a fragrance ingredient (salicylate ester) typically used at low concentrations but is a recognized contact allergen in fragrance mixes and can trigger irritation or allergic contact dermatitis in sensitized or highly reactive patients. While not a keratolytic active like salicylic acid, its primary risk is sensitization and cumulative exposure across multiple fragranced products, which is clinically relevant for eczema-prone and barrier-impaired skin. Given the potential for delayed allergy and flare provocation in sensitive populations, it warrants a significant irritancy score. Safety Notes: Amyl Salicylate is primarily used as a fragrance material, so at the low end it appears in many leave-on skincare products (creams/lotions/serums) at trace levels around ~0.0001–0.01% as part of a perfume compound. In fragranced body lotions, body butters, and scented cleansing products, it is commonly found at higher fragrance-loading levels (~0.05–0.3%), with the highest consumer-available uses observed around ~0.5% in strongly fragranced products (often rinse-off or body care). Concentration is typically constrained by overall fragrance design and sensitization/allergen management rather than a functional skin-benefit dose, and finished-product labeling may not reflect its exact level when used within “parfum/fragrance.”

Amyris Balsamifera Bark Oil

Amyris balsamifera bark oil (amyris/sandalwood-like essential oil) is used primarily as a fragrance component at low concentrations, but it contains volatile terpenoid constituents that are well-documented triggers for irritant and allergic contact dermatitis in fragrance-sensitive and eczematous patients. Even when used below 1%, repeated leave-on exposure can contribute to cumulative barrier stress and sensitization risk, so I score it as a significant irritant/allergen concern for reactive skin. Safety Notes: In commercial skincare, Amyris balsamifera (amyris/sandalwood-like) bark oil is most often used as a fragrance/essential-oil component at trace to very low levels (commonly ~0.0001–0.05%) in leave-on creams/serums and rinse-off cleansers to impart scent while managing sensitization risk. The upper end is seen in consumer-available “essential-oil” balms, facial oils, and aromatherapy-style moisturizers where amyris is used as a primary odorant/fixative and can approach about 0.5–1.0% in leave-on products; higher levels are uncommon due to skin tolerance and fragrance allergen/IFRA-style exposure considerations.

Anacyclus Pyrethrum Root Extract

Anacyclus pyrethrum (pellitory) root extract is used in small amounts in cosmetics for “stimulating/energizing” or firming claims, and it contains alkylamides and related constituents that can produce a tingling, warming, or stinging sensation. While robust large-scale irritancy datasets are limited, its known counterirritant/rubefacient profile and documented potential for contact reactions in sensitive individuals justify treating it as an active botanical rather than an inert soothing extract. For eczema-prone or compromised skin, I consider it a notable irritation risk in real-world routines where it may layer with other actives. Safety Notes: In commercial skincare, Anacyclus Pyrethrum Root Extract is most often a low-dose botanical active used for firming/anti-aging claims, frequently appearing at ~0.001–0.1% in multi-ingredient serums and creams (especially when supplied as a standardized extract or as part of a proprietary blend). Higher-strength consumer products marketed as “spilanthol/anacyclus lifting” or intensive firming treatments can reach ~1–3% of the extract (as supplied), mainly in leave-on serums/ampoules; rinse-off products typically sit at the lower end due to brief contact time. No specific global maximum is set for this extract, so practical upper limits are driven by supplier usage guidance, sensory impact, and irritation risk rather than regulation.

Ananas Sativus Fruit Extract

Ananas sativus (pineapple) fruit extract is primarily used for antioxidant/conditioning benefits and may contain natural fruit acids and traces of proteolytic enzymes (e.g., bromelain), which can increase stinging and barrier disruption even at typical low cosmetic use levels. Clinical experience and patch-test patterns show fruit-derived extracts can provoke irritant reactions in eczema-prone or compromised skin, especially when layered with other actives. Given the variability of extract composition and the higher risk in sensitive populations, I rate it as moderate irritation potential. Safety Notes: In mainstream commercial skincare, Ananas Sativus (pineapple) fruit extract is often used as a label-claim botanical or minor sensorial/marketing additive in leave-on lotions/serums and rinse-off cleansers at very low levels (~0.001–0.1%), reflecting typical supplier-recommended use rates and cost/stability considerations. Higher consumer-available “enzymatic/exfoliating” masks and peel-type products that emphasize pineapple/fruit-enzyme benefits can use materially higher loads of the extract, most commonly ~1–3% and occasionally up to ~5% depending on the extract type (glycerin/propylene glycol/water-based) and overall formula tolerance. Concentrations above this are uncommon in OTC skincare because activity is usually delivered via standardized enzyme preparations (e.g., bromelain) rather than very high levels of crude fruit extract, and higher loads can create stability, odor/color, and irritation challenges, especially in leave-on formats.

Anastatica Hierochuntica Extract

Anastatica hierochuntica ("resurrection plant") extract is primarily a soothing/humectant-support botanical used at low concentrations (typically <1–3%) and is not known to have intrinsic keratolytic or strongly bioactive (acid/retinoid-like) irritation mechanisms. However, like many plant extracts it is a chemically complex mixture and can trigger irritant or allergic contact dermatitis in a small but meaningful subset of sensitive or eczematous patients, especially in leave-on products and when combined with multiple botanicals. Given limited robust patch-test data compared with standard actives and the need to protect highly reactive skin, I rate it as gentle but not “very gentle.” Safety Notes: In commercial INCI-based skincare, Anastatica hierochuntica (resurrection plant) extract is most often used as a marketing/claims botanical at very low levels (commonly around 0.001–0.1% active extract in emulsions/serums), with the lowest observed levels appearing in long INCI lists where it functions primarily as a label claim. Higher-strength consumer products (leave-on serums/ampoules and some soothing gels) can use 1–5% when the raw material is a glycerin/butanediol/water extract or similar supplier-grade extract, with 5% representing the upper end seen in OTC products before sensorial, stability, color/odor, and cost constraints typically limit further increases; rinse-off products generally sit toward the low end due to limited contact time.

Angelica Archangelica Root Oil

Angelica archangelica root oil is an essential oil used primarily for fragrance at low concentrations, but it contains volatile terpenes and naturally occurring sensitizers that are well-documented triggers of irritant and allergic contact dermatitis in patch-tested populations. Essential oils also add cumulative irritation burden when layered with other actives or used on compromised skin (e.g., eczema), where barrier disruption markedly increases reaction risk. Given the ingredient category’s established sensitization profile and the potential for significant flares in sensitive individuals, a high irritancy score is warranted for patient safety. Safety Notes: In commercial skincare, Angelica archangelica root oil is most often used as a fragrance/allergen-bearing essential oil component, with many leave-on products (creams, serums, facial oils) using it at trace levels around 0.0005–0.05% as part of a broader fragrance blend. Rinse-off products (cleansers, shower gels) commonly sit in the ~0.01–0.3% range due to lower sensitization concern and easier odor masking. The upper end observed in consumer-available “essential oil” and niche botanical balm/oil products can reach about 1–2% when used as a featured aromatic active, though such levels are constrained in practice by IFRA-style sensitization/phototoxicity risk management and strong odor impact in leave-on formats.

Angelica Polymorpha Sinensis Root Extract

Angelica polymorpha sinensis root extract is a botanical antioxidant/soothing extract typically used at low concentrations, but it contains multiple naturally occurring aromatic compounds (e.g., phthalides/coumarin-like constituents) that can act as irritants in reactive or barrier-impaired skin. While broad human irritation data are limited compared with standard actives, plant extracts show non-trivial rates of stinging/erythema in sensitive populations and can contribute to cumulative irritation in multi-step routines. Given the uncertainty and the higher risk profile in eczema-prone patients, I score it as mild rather than gentle. Safety Notes: In commercial skincare, Angelica Polymorpha Sinensis Root Extract (dong quai/Angelica sinensis) most often appears as a minor botanical in multi-extract blends, where finished-product use levels can be as low as ~0.0001–0.01% (especially when the supplier blend is added at 0.1–1% and the target extract is a small fraction). Leave-on toners/serums/creams commonly use it around 0.05–1% as a named botanical active, while the highest consumer-available “high botanical” or traditional-herbal positioning products (including masks/ampoules) can reach ~2–5% when the formula is built around the extract; rinse-off products generally sit toward the lower end due to cost/benefit and wash-off dilution.

Anhydroxylitol

Anhydroxylitol is a sugar-derived humectant used in leave-on products (often within the Aquaxyl complex) at low percentages to support barrier hydration and reduce transepidermal water loss. Available clinical/patch-test experience with polyol humectants suggests a low irritation profile, with reactions being uncommon and typically limited to very reactive or severely compromised skin. Because it is not a low-pH active, fragrance, or high-risk preservative, the overall irritation potential is very gentle, though not fully inert. Safety Notes: In commercial moisturizers/serums, anhydroxylitol is most often used as part of the Aquaxyl-type humectant complex (with xylitol and xylitylglucoside), where it can appear at very low levels (~0.05–0.2%) when the total complex is used around 0.5–1%. Higher-strength OTC leave-on hydration products commonly push the total complex to ~3–5%, which corresponds to roughly ~1–3% anhydroxylitol depending on the blend ratio; rinse-off formats (cleansers) tend to sit at the low end due to short contact time. There is no specific EU/FDA maximum for anhydroxylitol as a cosmetic ingredient, so the practical upper bound is set by formula aesthetics, tackiness, and overall polyol load rather than regulation.

Aniba Rosaeodora Wood Extract

Aniba rosaeodora (rosewood) wood extract is used primarily for fragrance and contains high levels of linalool and other aromatic terpenes, which are well-documented irritants and contact sensitizers in patch testing, especially after oxidation. Even at the low concentrations typical of fragrancing, reactive and eczematous skin has a meaningful risk of stinging, dermatitis flares, or delayed allergic contact dermatitis, so I score it as a significant irritation/sensitization concern for sensitive-skin use. Safety Notes: In commercial skincare, Aniba rosaeodora (rosewood) wood extract is most commonly used as a trace-level botanical/fragrance-support extract in leave-on creams/serums and rinse-off cleansers around 0.0001–0.05%, reflecting cost, potential sensitization concerns, and IFRA-style fragrance practice when the extract contains aromatic constituents. Higher-strength consumer products (often positioned as ‘natural perfumery’, aromatherapy-style facial oils, or botanical concentrates) can reach ~0.1–0.5% as a characterizing extract level, with concentrations above this uncommon in mainstream OTC skincare due to odor impact and tolerability.

Anisaldehyde

Anisaldehyde (p-methoxybenzaldehyde) is primarily used as a fragrance/flavor component at low concentrations, but fragrance chemicals are a leading cause of cosmetic adverse reactions. It has documented potential to trigger irritant and allergic contact dermatitis on patch testing, and in eczema-prone or barrier-impaired skin even small amounts can provoke significant flares. Given the sensitization risk and cumulative exposure from multiple fragranced products, I score it as a significant irritancy concern for sensitive skin. Safety Notes: Anisaldehyde is used primarily as a fragrance component/flavorant in cosmetics, so it is typically present at trace levels in finished products (often ~0.0001–0.01%) in leave-on creams/serums and rinse-off cleansers where it contributes to the perfume accord. At the high end, strongly fragranced consumer products (e.g., body mists, perfumes/eau de toilette marketed as cosmetics, and some heavily scented body care) can reach around ~0.05–0.2% as part of the overall fragrance mixture. Use levels are generally constrained by fragrance safety practices (IFRA guidance) and allergen/labeling considerations, so concentrations above ~0.2% are uncommon in over-the-counter skincare.

Annona Cherimola Fruit Extract

Annona cherimola (cherimoya) fruit extract is typically used at low concentrations as an antioxidant/soothing botanical, but like many plant extracts it contains a complex mix of proteins and phytochemicals that can trigger stinging or allergic-type reactions in reactive or eczematous skin. Controlled irritation data are limited and botanical extracts show meaningful variability between suppliers, so I do not treat it as inherently “gentle.” Given the potential for sensitization in compromised barriers and the lack of robust clinical reassurance, a mild irritancy score is the safest evidence-aligned assessment. Safety Notes: In commercial skincare, Annona cherimola (cherimoya) fruit extract is most often used as a minor botanical/antioxidant addition in leave-on serums, creams, and sheet masks at trace-to-low levels (commonly well under 0.1%), consistent with typical supplier-recommended use levels for fruit extracts. The upper end is observed in consumer-available “botanical-forward” formulas where the extract is a featured active or supplied as a concentrated glycerin/butanediol extract and dosed in the low single digits; ~5% represents a practical market ceiling for leave-on products before cost, odor/color, and stability/compatibility constraints usually limit further increases. Rinse-off cleansers typically sit toward the low end due to short contact time, while higher levels are predominantly seen in leave-on products.

Anogeissus Leiocarpus Bark Extract

Anogeissus leiocarpus bark extract is a polyphenol/tannin-rich botanical used mainly for antioxidant and anti-aging benefits, typically at low concentrations, but tannins can be astringent and sting compromised barriers. While widespread severe reactions are not well-documented, limited standardized patch-test data and the known irritancy potential of tannin-heavy extracts justify treating it as a mild risk for eczema-prone or post-procedure skin, especially in leave-on products. Safety Notes: In commercial skincare, Anogeissus leiocarpus bark extract (often supplied as a standardized anti-aging active in glycerin/propylene glycol) is frequently used at very low levels (~0.001–0.05%) in mass-market moisturizers and cleansers where it is a minor supportive botanical. Most leave-on anti-aging serums/eye products cluster around ~0.1–1%, while the highest consumer-available “booster”/concentrate-style formulations and some brand-actives based on vendor recommended-use maxima reach ~2–3% of the extract (as-supplied), typically in leave-on products; rinse-off uses are generally lower due to limited contact time. There are no specific FDA/EU maximum concentration limits for this botanical, so the upper end is driven primarily by supplier use-level guidance, stability, odor/color impact, and irritation tolerance.

Anthemis Nobilis Flower Extract

Anthemis nobilis (Roman chamomile) flower extract is used at low concentrations as a soothing/anti-inflammatory botanical, but it contains sesquiterpene lactones and other plant constituents that are recognized causes of allergic contact dermatitis, especially in atopic or highly reactive patients and those with Asteraceae (Compositae) sensitivity. Clinical patch-test literature and case reports consistently show that “calming” chamomile extracts can still sensitize or flare eczema, and risk increases with leave-on use and cumulative exposure in multi-botanical formulas. Given the non-trivial sensitization potential despite low typical use levels, a mild irritancy score is warranted for patient safety. Safety Notes: In mass-market and dermatological skincare, Anthemis Nobilis (Roman chamomile) flower extract is frequently used as a label-level soothing botanical at very low levels (often ~0.0001–0.05%) due to potent odor/color contribution and because many supplier extracts are pre-diluted in solvents/glycerin. In leave-on products positioned for calming/redness relief (toners, serums, creams) and in some “botanical-heavy” indie formulations, total use levels commonly reach ~0.1–2%, with the highest observed OTC consumer products using around 3–5% of the commercial extract (not essential oil), typically requiring preservation/solubilization control to manage stability and sensitization risk. Rinse-off cleansers/shampoos tend to sit toward the lower end versus leave-on soothing products, where higher levels are more feasible/marketed.

Apium Graveolens Extract

Apium graveolens (celery) extract is a botanical additive typically used at low concentrations for antioxidant/soothing claims, but celery contains furocoumarins and other sensitizing constituents that have documented associations with allergic contact dermatitis and can contribute to photosensitivity in susceptible individuals. In sensitive-skin and eczema populations, botanical extracts are a common trigger category in patch testing, and risk rises with leave-on use and cumulative exposure alongside other irritants. Given the non-essential benefit and credible sensitization/irritation potential despite low typical use levels, a moderate irritancy score is the safer clinically aligned assessment. Safety Notes: In mass-market leave-on skincare, Apium graveolens (celery) extract is commonly used as a minor botanical supportive ingredient, often at trace-to-low levels (~0.0005–0.1%) when supplied as a diluted extract in a blend or as part of a preservative/soothing complex. Mid-range “natural” serums, toners, and moisturizers typically place it around 0.1–1% as a named botanical. Higher-strength consumer-available products (botanical concentrates, booster serums, and some wash-off masks) can reach ~2–5% when the supplier material is a standardized/glycerin or glycol extract and sensorial/irritation limits are managed; above this is uncommon OTC due to odor/color, stability, and potential sensitization risk typical of aromatic plant extracts.

Apium Graveolens Seed Extract

Apium graveolens (celery) seed extract is a botanical extract typically used at low concentrations for antioxidant/soothing claims, but it contains naturally occurring aromatic constituents that have documented potential for contact allergy and irritant reactions in sensitized individuals. Celery (Apium) is a recognized allergen in other exposure contexts, and topical botanical extracts from this plant family can trigger dermatitis in eczema-prone or highly reactive skin. Given the real-world variability of extract composition and the heightened risk in compromised skin, I score it as a notable irritation/sensitization risk rather than a “gentle” additive. Safety Notes: In mass-market leave-on skincare, Apium Graveolens (Celery) Seed Extract is often used as a minor botanical component within preservative/antioxidant or “soothing” blends, commonly appearing at trace-to-low levels around 0.0005–0.1% active extract in the finished formula. More focused “botanical-active” serums, ampoules, and some natural/organic positioning products can use it as a featured extract or part of higher-load plant complexes, reaching ~1–3% in consumer OTC leave-on products; rinse-off formats typically sit toward the lower end due to brief contact time. No specific EU/FDA maximum applies to this INCI itself, so the upper end is mainly constrained by odor/color, skin sensitivity potential, and overall formula stability/clarity.

Arachidic Acid

Arachidic acid is a long-chain saturated fatty acid used in cosmetics primarily as an emollient/structuring agent at low percentages, and fatty acids of this type are generally well-tolerated on skin. It is not a low‑pH active and is not commonly associated with significant irritation in standard use, though any lipid component can occasionally provoke mild stinging or follicular/irritant reactions in highly reactive or barrier-impaired users. Given its typical low concentration and low intrinsic reactivity, I rate it as very gentle with a small but nonzero risk in severely sensitive populations. Safety Notes: Arachidic acid (C20:0) is most often present as a minor fatty-acid component of plant butters/waxes or as a co-structurant in emulsions, so in many mainstream leave-on creams/lotions it appears at trace-to-low levels (often around 0.001–0.1%) when added as part of a fatty-acid blend rather than as a headline active. Higher consumer-available levels occur in heavy body butters, balms, cleansing creams, and anhydrous stick products where long-chain fatty acids are used to build structure and slip; in those formats arachidic acid can be used at a few percent, with observed upper-end OTC formulations around ~5% when deliberately added for thickening/consistency. There are no specific EU/FDA maximum limits for arachidic acid as a cosmetic ingredient, so the practical ceiling is driven by texture, crystallization/whitening risk, and overall fatty-phase design rather than regulation.

Arachidyl Alcohol

Arachidyl alcohol is a long-chain fatty alcohol used mainly as an emollient/thickener (typically ~0.5–5%), and fatty alcohols of this type are generally well-tolerated with low inherent irritancy compared with short-chain alcohols. Clinical patch-test experience suggests irritation and true allergy are uncommon but not impossible, particularly in highly reactive or eczema-prone patients and in leave-on products with multiple barrier-stressing ingredients. Given the need to protect compromised skin while acknowledging rare reactivity, it fits a very gentle risk profile rather than fully inert. Safety Notes: Arachidyl Alcohol (a C20 fatty alcohol, often part of the arachidyl behenyl alcohol/glucoside lamellar system) appears at low levels (~0.05–0.3%) in emulsions where it functions as a minor co-structurant or slip/viscosity aid alongside other fatty alcohols. In consumer leave-on creams, balms, and barrier moisturizers using lamellar/emulsifier blends, combined fatty alcohol structuring can push arachidyl alcohol into the multi-percent range, with the highest OTC products observed around ~5–8% when used as a primary waxy thickener/structurant; rinse-off formats typically sit lower due to sensorial and deposition constraints. There is no specific EU/FDA concentration cap for this ingredient in cosmetics, so the upper end is mainly set by stability, texture, and consumer acceptability.

Arachidyl Glucoside

Arachidyl glucoside is a non-ionic alkyl polyglucoside surfactant/emulsifier typically used at low levels (about 0.5–5%) to stabilize emulsions and improve mild cleansing. Compared with harsher anionic surfactants, patch-test and clinical use data for APG-type glucosides generally show low irritation potential, but surfactant behavior means a small subset of highly reactive or barrier-impaired patients can still experience stinging or dryness. Given this low-but-nonzero risk in eczema-prone skin and cumulative exposure in routines, it best fits "very gentle" rather than inert. Safety Notes: Arachidyl Glucoside is most often encountered in consumer products as part of alkyl glucoside-based emulsifier/solubilizer blends (commonly with arachidyl and behenyl alcohol), where it can appear at trace-to-low levels (~0.05–0.3%) in leave-on creams/lotions depending on how the supplier blend is used and how INCI disclosure reflects minor components. In standard leave-on emulsions and gentle rinse-off cleansers, typical use levels are around ~0.5–2%, while higher-strength consumer-available formulations (very rich barrier creams/balms or emulsifier-concentrate systems) can reach ~3–5% when the emulsifying system relies heavily on this glucoside component. This ingredient is not generally subject to specific maximum concentration limits under major cosmetics regulations, with practical upper limits driven by texture, viscosity, and stability rather than safety caps.

Arachidyl Propionate

Arachidyl Propionate is a fatty ester (emollient/skin-conditioning agent) typically used at low percentages to improve slip and barrier feel, and fatty esters in this class are generally well-tolerated in clinical use. It is not an acid, solvent, fragrance component, or preservative, and it has low inherent reactivity, so irritation potential is usually minimal even in sensitive skin. Rare individual intolerance is still possible, but based on its chemistry and typical use levels it best fits the 'very gentle' category. Safety Notes: Arachidyl Propionate is a waxy fatty-acid ester emollient/skin-feel modifier that appears at trace-to-low levels in many leave-on creams/lotions (often as part of an emollient blend), with commercial products commonly starting around ~0.01–0.1% when used primarily for slip and sensory tuning. In high-lipid, consumer-available body butters, balms, and barrier creams it can be used as a primary emollient within the oil phase and is observed up to ~2–3%, beyond which texture, waxiness, and cost typically limit further increases. It is less common in rinse-off formats and, when present, is generally kept toward the low end due to deposition inefficiency and cost/benefit.

Arachis Hypogaea Oil

Arachis Hypogaea (peanut) oil is primarily an emollient used at relatively high concentrations in creams and ointments, and while it is often well-tolerated, it is not reliably “non-irritating” in sensitive populations. Patch-test and clinical experience show low-to-moderate rates of irritation/sensitization concerns, with particular safety relevance in atopic dermatitis where reactivity and allergy risk are higher. Given its frequent leave-on use and the potential for clinically meaningful reactions in eczema-prone patients, a mild irritancy score is warranted. Safety Notes: In commercial skincare, Arachis Hypogaea (Peanut) Oil is often used at very low levels (~0.05–1%) as an emollient/lipid component within creams, lotions, cleansers, and balms where it functions as part of the oil phase. Mid-range usage (~2–20%) is common in richer body creams, massage products, and cleansing oils, while the highest strengths occur in consumer-available body oils and carrier-oil products marketed as pure peanut oil, which can be 100% (leave-on); rinse-off soaps/body washes may also include it but typically at lower percentages due to surfactant systems. There is no specific EU/FDA cosmetic concentration cap for peanut oil itself, but allergen sensitization risk drives labeling/market choices and tends to limit use in many facial products.

Arbutin

Arbutin is a tyrosinase-inhibiting brightening agent typically used around 1–2% (alpha-arbutin) or higher for beta-arbutin, and it is generally well-tolerated with low rates of stinging or erythema in clinical use. However, in highly reactive or eczema-prone skin, irritation can still occur—especially when combined with other actives (acids/retinoids) or in compromised barriers—so it is best classified as gentle but not inert. Safety Notes: In consumer skincare, arbutin is most often used in leave-on serums/creams, with low-end inclusion levels around 0.05–0.2% in brightening moisturizers and multi-active formulas where it is not a hero active. Mainstream OTC arbutin serums commonly fall around ~1–2%, while high-strength consumer-available “alpha-arbutin” booster serums are marketed and formulated up to about 10% (higher levels are uncommon due to diminishing solubility/stability and color/odor changes over time). Rinse-off products typically sit at the lower end because of short contact time.

Arbutus Unedo Fruit Extract

Arbutus unedo (strawberry tree) fruit extract is typically used at low concentrations as an antioxidant/soothing botanical, but it is a complex mixture (polyphenols, organic acids, trace volatile components) with variable composition that can trigger stinging or irritation in reactive and eczematous skin. While it is not a high-potency “active” like exfoliating acids, botanical extracts show a measurable rate of irritant and occasional allergic reactions in patch testing populations, especially on compromised barriers or when layered with other actives. Given patient-safety considerations and the unpredictability of botanical extracts across suppliers, I rate it as mild with occasional sensitivity possible. Safety Notes: In commercial skincare, Arbutus unedo (strawberry tree) fruit extract is most often used as a minor botanical/antioxidant component in multi-extract blends, where the finished-product use level commonly falls around 0.001–0.1% (especially in lotions, toners, and cleansers). Higher-strength consumer leave-on serums and brightening/antioxidant products that feature the extract more prominently are typically formulated around ~0.5–2%, with the upper end observed in niche “single-hero” botanical formulas and concentrated ampoules reaching ~3–5% depending on supplier potency/solids and sensory constraints. No specific EU/FDA maximum applies to this INCI beyond general cosmetic safety obligations, so the practical ceiling is usually set by extract solvent system, color/odor, and stability rather than regulation.

Arctium Lappa Root Extract

Arctium lappa (burdock) root extract is a botanical skin-conditioning/soothing ingredient typically used at low concentrations (often <1–2%), and it is generally well tolerated in standard cosmetic patch-test experience. However, as a plant extract it contains multiple bioactive constituents and has a non-trivial risk of irritant reactions or allergic contact dermatitis in highly reactive or eczema-prone patients, especially in compromised skin barriers or leave-on routines. Given the variability in extract composition and the sensitive-skin safety priority, a mild (0.4) irritancy score is the most clinically cautious match. Safety Notes: In mass-market leave-on toners/serums and many rinse-off shampoos/cleansers, Arctium Lappa (Burdock) Root Extract is commonly used as a label-claim botanical at very low levels (often ~0.0005–0.1% active extract, especially when supplied as a dilute glycerin/propylene glycol extract). Higher concentrations are found in “botanical-heavy” acne/oily-scalp products, masks, and herbal scalp tonics where the extract is a primary functional component, reaching ~1–5% in OTC consumer formulas depending on the extract’s solvent system and solids content. This range reflects real commercial practice for both leave-on and rinse-off products; above ~5% is uncommon due to cost, odor/color impact, and stability/sensory constraints rather than regulatory limits.

Arctostaphylos Uva Ursi Leaf Extract

Arctostaphylos uva-ursi (bearberry) leaf extract is used for brightening/antioxidant effects (often via arbutin and related phenolics/tannins) typically around ~0.1–2% in leave-on products. Botanical extracts—especially those containing tannins/phenolic compounds—show a measurable rate of irritant reactions on sensitive or eczematous skin in patch testing and real-world use, and can add cumulative irritation when combined with other actives (acids/retinoids). Given the variability in extract composition and the higher risk in compromised skin, I score it as moderate and recommend patch testing for reactive patients. Safety Notes: In commercial brightening and “spot corrector” leave-on products, Uva Ursi (bearberry) leaf extract is frequently used at very low levels (~0.01–0.1%) as part of multi-extract botanical blends where it serves as label-claim support rather than the primary active. Dedicated consumer brightening serums/creams sometimes use it as a key botanical active around 1–3%, and high-strength OTC formulations (typically leave-on) are observed up to about 5% extract, with higher levels uncommon due to color/odor, solubility, and irritation risk tied to arbutin-like phenolics; rinse-off products are generally at the lower end because of short contact time.